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Abstract

Pollinators are a key component of global biodiversity, providing vital ecosystem services to crops and wild plants. There is clear evidence of recent declines in both wild and domesticated pollinators, and parallel declines in the plants that rely upon them. Here we describe the nature and extent of reported declines, and review the potential drivers of pollinator loss, including habitat loss and fragmentation, agrochemicals, pathogens, alien species, climate change and the interactions between them. Pollinator declines can result in loss of pollination services which have important negative ecological and economic impacts that could significantly affect the maintenance of wild plant diversity, wider ecosystem stability, crop production, food security and human welfare.

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... In recent years, several studies have reported important declines of different pollinator taxa (Biesmeijer et al., 2006;IPBES, 2016;Potts et al., 2010), including reductions in the abundance and diversity of wild bees in Europe, mainly attributed to anthropogenic drivers such as habitat fragmentation, agricultural intensification, and climate change (Biesmeijer et al., 2006;Potts et al., 2010). The intensification of agricultural landscapes in particular has reduced habitat diversity and availability (Tscharntke et al., 2005), which threatens wild bee populations that are strongly dependent on natural and semi-natural habitats (Saturni et al., 2016). ...
... In recent years, several studies have reported important declines of different pollinator taxa (Biesmeijer et al., 2006;IPBES, 2016;Potts et al., 2010), including reductions in the abundance and diversity of wild bees in Europe, mainly attributed to anthropogenic drivers such as habitat fragmentation, agricultural intensification, and climate change (Biesmeijer et al., 2006;Potts et al., 2010). The intensification of agricultural landscapes in particular has reduced habitat diversity and availability (Tscharntke et al., 2005), which threatens wild bee populations that are strongly dependent on natural and semi-natural habitats (Saturni et al., 2016). ...
... Critical voices from the scientific and political arenas have called for maintaining sustainable and healthy insect pollination (Gill et al., 2016). Global concern about the fate of pollinators has resulted in several continental, national, and regional programmes intended to tackle pollinator declines (Potts et al., 2010). Considering the potential repercussions on agricultural productivity, the European Union has proposed a series of management practices to promote pollinator conservation and enhance pollination services (Scheper et al., 2013). ...
Article
Pollinator conservation has become a key challenge to achieve sustainable agricultural landscapes and safeguard food supplies. Considering the potential negative effects of pollinator decline, international efforts have been developed to promote agri-environmental measures and pollinator-friendly management practices. However, little effort has been devoted to farmers' perceptions and knowledge about pollinators, or to farmers' role in enhancing pollination. We administered 376 face-to-face questionnaires in four areas of Spain with different dominant pollinator-dependent crops, to assess the factors behind farmers' perceptions, knowledge, and practices adopted to promote pollination. Overall, 92.7% of the respondents recognized that pollinator insects are necessary for crop production, and 73.4% perceived pollinator decline in their farms. We found that farmers had moderate knowledge about pollinators (6.1 ± 1.8, on a 1-10 scale). The most applied practices to promote pollinators were reducing insecticide spraying (53.2% of respondents), diversifying crops (42.8%), and increasing fallow fields (39.1%). Factors such as education, age, concern about the pollinator crisis, and professional dedication to agriculture strongly influenced farmers' knowledge and current application of pollinator-friendly practices. Implications of our results for the ongoing reform of the Common Agricultural Policy are discussed, highlighting the need to increase engagement and trust of farmers through communication and technical assistance.
... Overall, the abundance of terrestrial insects has indeed deceased by 9% per decade and the wild bees are not an exception to the rule [8]. Literature about the deleterious impact of stressors on wild bees is abundant [9,10]. To slow down their negative impacts, the development of national and regional initiatives has been more and more associated with the implementation of restoration and protection actions for pollinators for the last few years. ...
... The scientific community has focused on assessing the extent of the decline and studying the factors responsible for the population regressions [59]. Aside from natural hazards recently shown to have a non-negligible impact on wild pollinators (e.g., fire, drought, hydrological and geophysical events; [60]), global warming, agricultural intensification, habitat homogenization as well as diseases and pathogens strongly affect wild bee populations [9,18]. While each of the factors alone [9] as well as some of the possible interactions [10,61] have been widely studied in several continents worldwide, a strong knowledge gap lies probably in the quantification of the respective impacts from the different threats coupled with the use of historical collections [62]. ...
... Aside from natural hazards recently shown to have a non-negligible impact on wild pollinators (e.g., fire, drought, hydrological and geophysical events; [60]), global warming, agricultural intensification, habitat homogenization as well as diseases and pathogens strongly affect wild bee populations [9,18]. While each of the factors alone [9] as well as some of the possible interactions [10,61] have been widely studied in several continents worldwide, a strong knowledge gap lies probably in the quantification of the respective impacts from the different threats coupled with the use of historical collections [62]. The spatial and temporal correlations of most of the decline factors render the assessment particularly challenging. ...
Article
Full-text available
Abstract: Wild bees are facing a global decline mostly induced by numerous human factors for the last decades. In parallel, public interest for their conservation increased considerably, namely through numerous scientific studies relayed in the media. In spite of this broad interest, a lack of knowledge and understanding of the subject is blatant and reveals a gap between awareness and understanding. While their decline is extensively studied, information on conservation measures is often scattered in the literature. We are now beyond the precautionary principle and experts are calling for effective actions to promote wild bee diversity and the enhancement of environment quality. In this review, we draw a general and up-to-date assessment of the conservation methods, as well as their efficiency and the current projects that try to fill the gaps and optimize the conservation measures. Targeting bees, we focused our attention on (i) the protection and restoration of wild bee habitats, (ii) the conservation measures in anthropogenic habitats, (iii) the implementation of human made tools, (iv) how to deal with invasive alien species, and finally (v) how to communicate efficiently and accurately. This review can be considered as a needed catalyst to implement concrete and qualitative conversation actions for bees.
... Just as demands for crop pollination are rising, one consequence of this agricultural expansion and intensification has been the severe depletion of nesting and floral resources (Baude et al., 2016;Biesmeijer et al., 2006;Scheper et al., 2014) that support the health and survival of wild pollinator populations (Goulson et al., 2015;Kennedy et al., 2013;Potts et al., 2010Potts et al., , 2016Vanbergen et al., 2018). Indeed, landscape simplification and homogenization, along with intensive use of pesticides associated with large-scale agriculture, are among the leading causes of a worldwide pollinator decline (Brittain et al., 2010;Potts et al., 2010;Vanbergen and The Insect Pollinators Initiative, 2013;Zattara and Aizen, 2019). ...
... Just as demands for crop pollination are rising, one consequence of this agricultural expansion and intensification has been the severe depletion of nesting and floral resources (Baude et al., 2016;Biesmeijer et al., 2006;Scheper et al., 2014) that support the health and survival of wild pollinator populations (Goulson et al., 2015;Kennedy et al., 2013;Potts et al., 2010Potts et al., , 2016Vanbergen et al., 2018). Indeed, landscape simplification and homogenization, along with intensive use of pesticides associated with large-scale agriculture, are among the leading causes of a worldwide pollinator decline (Brittain et al., 2010;Potts et al., 2010;Vanbergen and The Insect Pollinators Initiative, 2013;Zattara and Aizen, 2019). Such effects compromise agricultural productivity because visitation by wild bees enhances yield in most pollinator-dependent crops (Brittain et al., 2013a;Garibaldi et al., 2013;Potts et al., 2016;Rader et al., 2016). ...
Chapter
Increasing honey demand and global coverage of pollinator-dependent crops within the context of global pollinator declines have accelerated international trade in managed bees. Bee introductions into agricultural landscapes outside their native ranges have triggered noteworthy invasions, especially of the African honey bee in the Americas and the European bumble bee Bombus terrestris in southern South America, New Zealand, Tasmania, and Japan. Such invasions have displaced native bees via competition, pathogen transmission, and invaders' capacity to exploit anthropogenic landscapes. At high abundance, invasive bees can degrade the mutualistic nature of many of the flower-pollinator interactions they usurp, either directly by affecting flower performance or indirectly by reducing the pollination effectiveness of other flower visitors, with negative consequences for crop pollination and yield. We illustrate such effects with empirical examples, focusing particularly on interactions in the Americas between B. terrestris and raspberry and between the African honey bee and coffee. Despite high bee abundance and flower visitation in crops, theoretical and empirical evidence suggests that agricultural landscapes of pollinator-dependent crops dominated by invasive bees will be less productive than landscapes with more diverse pollinator assemblages. Safeguarding future crop yield and aiding the transition to more sustainable agricultural landscapes and practices require we address this impact of invasive bees. Actions include tighter regulation of the trade in bees to discourage further invasions, reducing invasive bee densities and dominance, and active enhancement of ecological infrastructure from field to landscape scales to promote wild bee abundance and diversity for sustained delivery of crop pollination services.
... Insect pollinators are likewise declining as land-use changes are globally quickened by anthropological impacts. (Potts et al. 2010) .The number of butterflies is declining at an alarming rate in different areas because destruction their habitat has been carried out on a massive scale. As a result, the balance of total ecosystem has been affected. ...
... Although reduction of habitat will reduce population sizes, most often an extreme weather event causes the extinction of a rare and localized butterfly (Murphy, Freas, and Weiss 1990) Many studies have already shown that butterflies are among the species that have responded the most to climate change. Climate change affect butterflies life cycles, flight times, essential interactions, and ultimately survival (Potts et al. 2010). Climate change can likewise influence flight times in butterflies. ...
Conference Paper
Forest ecosystems are one of the most important habitats for butterflies in the tropical regions. Butterfly plays an important role in pollination and it is one of the key bioindicators of forest health and environment. Evidence suggest that butterfly diversity is affected by different abiotic and biotic factors in forest ecosystems. Several studies have been focused on the effects of abiotic factors on butterfly diversity. However, there is a substantial lack regarding the effects of biotic factors on butterfly biodiversity in tropical forest ecosystems. This study was conducted in order to explore the butterfly species composition and to investigate the effects of biotic factors on butterfly biodiversity in Khadimnagar National Park, Sylhet, a tropical semi-evergreen forest of Bangladesh. A stratified random sampling method was used to select plots in the study areas. The whole forest area was divided into 3 types of habitats namely, semi-natural forest, plantation, and forest boundary. Total 45 plots in transect line, 15 from each habitat, were selected for the data collection. The size of each plot was 30 m × 10 m. From each plot, 3 sub-plots (1m×1m) were taken randomly for herb and shrub species survey. Total 38 butterfly species belonging to 5 families and 29 genera were found in the study area. The effects of 8 biotic factors (habitat type, no. of plant species, tree cover (%), herb cover (%), shrub cover (%), canopy openness, no. of native plant species and no. of non-native plant species) on butterfly diversity were tested in the study areas. Among the selected 8 biotic factors, 3 of them namely, habitat type (P= 0.0001), shrub cover (P= 0.0408) and herb cover (P= 0.0370) have significant effects on butterfly diversity. Results showed that forest boundary consisted of higher number of butterfly species (30) compared to semi-natural forest (10) and plantation (23). Shrub and herb cover (%) are other two factors which had significant effects on butterfly diversity. Results depicts that butterfly species preferred intermediate level of shrub and herb cover which ranges from 30% to 55%. The study recommends that forest boundary is the most diverse habitat for butterfly diversity. In addition, around 50 % shrub and herb cover should be maintained in the forest areas to increase the butterfly diversity in tropical forest ecosystems. Results suggest that butterfly species prefer intermediate level of disturbance. Keywords: Butterfly diversity, Disturbance, Habitat, Plant cover, Tropical forest
... N early 90% of flowering plants rely on animal pollinators for reproduction 1 , and as a consequence, angiosperm biodiversity relies on stable mutualisms between plants and pollinators 2,3 . As the world's human population has grown, native vegetation has been converted to intensively humanmanaged and urbanized landscapes 4 that, along with increased use of pesticides, have demonstrably reduced pollinator abundance and diversity even in natural areas [4][5][6][7][8] . Although insect declines are now recognized broadly, wild bee species may be particularly vulnerable to land-use change 9,10 and these represent the most important pollinators of flowering plants globally 5,11 . ...
... As the world's human population has grown, native vegetation has been converted to intensively humanmanaged and urbanized landscapes 4 that, along with increased use of pesticides, have demonstrably reduced pollinator abundance and diversity even in natural areas [4][5][6][7][8] . Although insect declines are now recognized broadly, wild bee species may be particularly vulnerable to land-use change 9,10 and these represent the most important pollinators of flowering plants globally 5,11 . Moreover, how plant reproduction responds to land use via any declines in pollinators has important implications for much of the world's flora 12 , yet the effects of land use changes on pollen limitation of wild plant reproduction have not been evaluated on a global scale 13 . ...
Article
Full-text available
Land use change, by disrupting the co-evolved interactions between plants and their pollinators, could be causing plant reproduction to be limited by pollen supply. Using a phylogenetically controlled meta-analysis on over 2200 experimental studies and more than 1200 wild plants, we ask if land use intensification is causing plant reproduction to be pollen limited at global scales. Here we report that plants reliant on pollinators in urban settings are more pollen limited than similarly pollinator-reliant plants in other landscapes. Plants functionally specialized on bee pollinators are more pollen limited in natural than managed vegetation, but the reverse is true for plants pollinated exclusively by a non-bee functional group or those pollinated by multiple functional groups. Plants ecologically specialized on a single pollinator taxon were extremely pollen limited across land use types. These results suggest that while urbanization intensifies pollen limitation, ecologically and functionally specialized plants are at risk of pollen limitation across land use categories. An insufficient amount of pollen transfer by pollinators (pollen limitation) could reduce plant reproduction in human-impacted landscapes. Here the authors conduct a global meta-analysis and find that pollen limitation is high in urban environments and depends of plant traits such as pollinator dependency.
... The factors that cause colony losses in honey bees are very diverse. Possible loss or decline of pollinators are thought to be due to a combined result of destruction and degradation of habitats, pollution and pesticide related toxicity, pathogen and parasite related diseases, and invasive species many of which also effect honey bees (de la Rua, Jaffé, Dall'Olio, Muñoz, & Serrano, 2009;Goulson, Nicholls, Botías, & Rotheray, 2015;Potts et al., 2010;van der Zee, Gray, Pisa, & de Rijk, 2015). ...
... In that case, natural selection would counterweigh the effect of gene flow between populations and random genetic drift. As a result, it is inevitable to observe different combinations of allele frequencies in various populations (Savolainen, Lascoux, & Merilä, 2013). Sudden changes are to be expected where selection is relatively strong while a smoother transition would be observed in regions where gene flow between populations is higher (Beekman, Allsopp, Wossler, & Oldroyd, 2008). ...
Article
Full-text available
Quantitative studies concerning the impact of climate change on pollinators are generally lacking. Relationship between honey bee diversity, present local adaptations and adaptive capacity of subspecies and ecotypes in the face of climate change is an urgent but rather poorly studied topic worldwide. Actually, such an effort lies at the crossroads of various fields of inquiry. Those include conservation of local honey bee diversity, breeding various local stocks for desirable traits, and enabling resilient ecosystem services. With the ever-increasing availability of genomic tools, now it is more probable than ever to simultaneously fill such gaps. Current knowledge and growing awareness on honey bee diversity in Turkey let us progress into a more systematic utilization of this resource through development of climate-conscious models. Here we provide a framework that takes genomic diversity into account for assessing and monitoring various aspects of species’ response to climate change which can potentially lead to drastic impacts.
... There are scientific concerns regarding to ecosystemic service of pollination due to the decline of insect pollinators (Ollerton et al., 2011;Sánchez-Bayo and Wyckhuys, 2019;Steffan-Dewenter et al., 2005). Studies in the honey bee Apis mellifera indicate that the synergistic effects of several environmental stressors drive this phenomenon, in particular the role of agrochemical exposure (Potts et al., 2010). ...
... Changes in gene expression were reported in larvae and worker honey bees fed with residual doses of neonicotinoids, where genes related to lipid, carbohydrate, xenobiotic metabolism, stress response, and miRNAs were altered (Derecka et al., 2013;Koo et al., 2015;Potts et al., 2010;Siede et al., 2012). Furthermore, Koo et al. (2015) showed that gene expression of hsp70, hsp90, and grp78, which have chaperon functions to overcome stresses, negatively correlated with increasing neonicotinoid doses in worker honey bees. ...
Article
Full-text available
Neonicotinoid insecticides are potent agonists of nicotinic acetylcholine receptors and are a major factor in the decline of pollinators worldwide. Several studies show that low doses of this neurotoxin influence honey bee physiology, however, little is known about how insecticides interact with other environmental variables. We studied the effects of two neonicotinoid Imidacloprid doses (IMD, 0, 2.5, and 10 ppb), and three temperatures (20, 28, and 36°C) on gene expression in the brains of worker honey bees (Apis mellifera). Using qRT-PCR we quantified the expression of eight key genes related to the nervous system, stress response, and motor and olfactory capacities. Gene expression tended to increase with the low IMD dose, which was further intensified in individuals maintained in the cold treatment (20°C). At 20°C the octopamine receptor gene (oa1) was underexpressed in bees that were not exposed to IMD, but overexpressed in individuals exposed to 2.5 ppb IMD. Also, heat shock proteins (hsp70 and hsp90) increased their expression at high temperatures (36°C), but not with IMD doses. These results suggest that despite the low insecticide concentrations used in this study (a field-realistic dose), changes in gene expression associated with honey bee physiological responses could be induced. This study contributes to the understanding of how neonicotinoid residual doses may alter honey bee physiology.
... Habitat destruction, loss of flower resources, and increased use of pesticides (neonicotinoids and others) are causing declines in pollinator abundance and diversity (Potts et al. 2010(Potts et al. , 2015. Decline of pollinators in North-West Europe is well documented (Biesmeijer et al. 2006;Carvalheiro et al. 2013). ...
... Despite the fact that some of them have additionally alternative strategies to ensure reproduction, such as spontaneous self-pollination, vegetative propagation, or apomixis, the importance of bees and other insect pollinators is clear. Pollinator decline (Potts et al. 2010(Potts et al. , 2015BeeInformed 2014BeeInformed -2015 is therefore an important hazard for the existence and production of medicinal plants. This predominant dependence of medicinal plants on insects for pollination provides also an excellent potential for using these pollen vectors in the context of biological control of insect pests and diseases via entomovectoring (Hokkanen and Menzler-Hokkanen 2009;Smagghe et al. 2012;Hokkanen et al. 2015;Menzler-Hokkanen and Hokkanen 2017). ...
Chapter
Most people are aware that pollinators are in trouble, and with them agricultural products worth more than $200 billion annually (FAO. Pollinators vital to our food supply under threat. http://www.fao.org/news/story/en/item/384726/icode/, 2017). Pollinators are fundamental to maintaining both biodiversity and agricultural productivity, but habitat destruction, loss of flower resources, and increased use of pesticides (particularly neonicotinoids) are causing declines in their abundance and diversity.
... Numerous pollinator species of concern have been identified in the Great Plains, including many prairie-specialist butterflies and several bumble bee species ( Table 1 ; Hatfield et al. 2012 ). Multiple interacting factors are linked to pollinator declines, but drivers causing declines vary across regions ( Winfree et al. 2009 ;Potts et al. 2010 ;Vanbergen et al. 2013 ;Koh et al. 2016 ;Fig. 2 ). Although grasses are the dominant biomass in the Great Plains, forbs (i.e., herbaceous flowering plants) contribute most to species richness and diversity and exhibit the greatest responses to environmental change ( Glenn and Collins 1990 ;Howe 1994 ;Steuter et al. 1995 ). ...
... Work outside the Great Plains also suggests that bee community responses to grassland fire may be partially driven by increased nesting habitat for ground-nesting bees (Smith DiCarlo et al. 2019 ). A meta-analysis of the effects of different factors on bee communities at a global scale found that fire did not have a significant impact on abundance or richness ( Winfree et al. 2009 ), but the small number of studies on fire and bees limited the statistical power to detect differences ( Potts et al. 2010 ). ...
Article
Full-text available
Recent global declines of pollinator populations have highlighted the importance of pollinators, which are undervalued despite essential contributions to ecosystem services. To identify critical knowledge gaps about pollinators, we describe the state of knowledge about responses of pollinators and their foraging and nesting resources to historical natural disturbances and new stressors in Great Plains grasslands and riparian ecosystems. In addition, we also provide information about pollinator management and research needs to guide effort s to sustain pollinators and by extension, flowering vegetation, and other ecosystem services of grasslands. Although pollinator responses varied, pollinator specialists of disturbance-sensitive plants tended to decline in response to disturbance. Management with grazing and fire overall may benefit pollinators of grasslands, depending on many factors; however, we recommend habitat and population monitoring to assess outcomes of these disturbances on small, isolated pollinator populations. The influences and interactions of drought and increasingly variable weather patterns, pesticides, and domesticated bees on pollinators are complex and understudied. Nonetheless, habitat management and restoration can reduce effects of stressors and augment floral and nesting resources for pollinators. Research needs include expanding information about 1) the distribution, abundance, trends, and intrare-gional variability of most pollinator species; 2) floral and nesting resources critical to support pollinators; 3) implications of different rangeland management approaches; 4) effects of missing and reestablished resources in altered and restored vegetation; and 5) disentangling the relative influence of interacting disturbances and stressors on pollinator declines. Despite limited research in the Great Plains on many of these topics, consideration of pollinator populations and their habitat needs in management plans is critical now to reduce future pollinator declines and promote recovery. Published by Elsevier Inc. on behalf of The Society for Range Management. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
... One such study quantified and valued pollination at USD 47 ha −1 year −1 in combined food and energy agroforestry in Denmark [132]. Despite the significant negative impact on the agriculture industry, the decline in pollinators is mainly due to intensive agriculture [133]. Varah et al. [134] stated that conventional farming methods focus on providing just one ecosystem service-productivity-by reducing environmental complexity by growing intensive monocultures with better economies of scale. ...
... In addition, the lower exposure to pesticides and runoff in AFS reduces the harmful effects to pollinator populations. The findings were supported by a field study of four silvopastoral and two silvoarable AFS in the UK by Potts et al. [133], where butterfly diversity was significantly higher for AFS than for the control plots (agricultural monocultures growing the same crop as the agroforestry treatment but without the trees). A review by Varah et al. [136] found that temperate AFS provide greater pollination service than monocultures: AFS had twice as many solitary bees and hoverflies, and the species richness of solitary bees was approximately 10.5 times greater in AFS. ...
Article
Full-text available
Soil degradation is a global concern, decreasing the soil’s ability to perform a multitude of functions. In Europe, one of the leading causes of soil degradation is unsustainable agricultural practices. Hence, there is a need to explore alternative production systems for enhanced agronomic productivity and environmental performance, such as agroforestry systems (AFS). Given this, the objective of the study is to enumerate the major benefits and challenges in the adoption of AFS. AFS can improve agronomic productivity, carbon sequestration, nutrient cycling, soil biodiversity, water retention, and pollination. Furthermore, they can reduce soil erosion and incidence of fire and provide recreational and cultural benefits. There are several challenges to the adoption and uptake of AFS in Europe, including high costs for implementation, lack of financial incentives, limited AFS product marketing, lack of education, awareness, and field demonstrations. Policies for financial incentives such as subsidies and payments for ecosystem services provided by AFS must be introduced or amended. Awareness of AFS products must be increased for consumers through appropriate marketing strategies, and landowners need more opportunities for education on how to successfully manage diverse, economically viable AFS. Finally, field-based evidence is required for informed decision-making by farmers, advisory services, and policy-making bodies.
... However, there is clear evidence of the recent decline in bees colonies, and parallel decline in the population of plant species that are dependent on bees for outcrossing (Biesmeijer et al., 2006). The decline in honey bee colonies has been reported in the different parts of the world (Potts et al., 2010) and also in India (Sihag 2014). If the declining trend continues, it may reduce seed and fruit production from many outcrossing crops. ...
... One of the major causes which have often been linked with pollinators decline is degradation and loss of natural habitats and floral resources due to developmental activities, e.g., intensification of agriculture and urbanization (Potts et al., 2010;Hülsmann et al., 2015). Therefore, enhancing the availability and diversity of floral resources is one of the major strategies for conserving honey bee population and diversity. ...
Article
Full-text available
Honey bees are an important component of the agricultural ecosystem and provide valuable pollination service. Cultivation of annual ornamental flowering plants is being recognized as a suitable options to compensate for the loss of natural floral resources for conserving the declining population of the honey bee. The capitulum/ inflorescence of commonly grown annual ornamental flowers of the Asteraceae family differs in morphology. The morphology of flowers affects the abundance and diversity of bee species. Therefore, the present study was conducted with an aim to study the influence of commercially cultivated flowering plants of India (Calendula officinalis, Chrysanthemum indicum, Glebionis segetum, Tagetes patula and Tagetes erecta) on honey bee diversity and abundance in the hot semi-arid environment. The capitulum of these plant species differed significantly in length and diameter of the corolla tube. It was observed that dwarf (Apis florea) and giant (Apis dorsata) honey bee were the most common visitors, however, the abundance of both bee species was significantly different (P<0.01) on different plant species. Plants with relatively longer (15.25-18.9 mm) and wider corolla tube (Tagetes erecta and Tagetes patula) were visited by both the bee species. However, plants having short (5.0-6.5 mm) and narrow (1.0-1.33 mm) corolla tubes (Calendula officinalis, Chrysanthemum indicum, Glebionis segetum) were dominantly visited by only Apis florea. Therefore, the cultivation of Tagetes patula and Tagetes erecta may enhance the population and conservation of both Apis florea and Apis dorsata, while Calendula officinalis, Chrysanthemum indicum, and Glebionis segetum may only enhance the population of Apis florea in the arid and semi-arid zone of India.
... In addition, B. affinis Cresson, 1863, once found throughout Midwestern and Eastern North America, has recently been listed as federally endangered in the United States, having experienced a 90% decline across its range (USFWS 2017). The observed declines are likely due to several interacting factors, including introduced parasites and pathogens, agricultural insecticides and herbicides, climate change, and habitat simplification and loss (Colla et al. 2006;Potts et al. 2010;Cameron et al. 2011;Szabo et al. 2012;Goulson et al. 2015;Soroye et al. 2020). ...
... Habitat-dependent differences in bumble bee populations can inform conservation planning. There is currently a critical need to understand how habitat and habitat management impacts bumble bee populations (Potts et al. 2010) as in the Midwest, many bumble bees are facing significant declines, yet the degree to which habitat is impacting these populations remains unclear (Grixti et al. 2009). Consistent with findings from others who have shown that the restoration of native tallgrass prairie is an effective tool in the recovery of native bee populations (Smith et al. 2016;Tonietto et al. 2017;Paterson et al. 2019;Stein et al. 2020), our study more specifically suggests that nativedominant restored prairie habitat can be very important in supporting a diverse bumble bee community in the Midwest. ...
Article
1. Bumble bees are important pollinators in both natural and anthropogenic systems. In recent years, some species have suffered declines, including in the American Midwest. While loss of floral resources and grassland habitat may contribute to these declines, little is known about how native versus agricultural grasslands affect bumble bee populations. 2. We conducted 3 years of bumble bee population and floral use surveys across restored tallgrass prairie, bison pasture, and cattle pasture in Northern Illinois. 3. We found 1.75-3.5 times more bumble bees in native plant dominant tallgrass prairie than in exotic-dominant pasture sites. In addition, bumble bees were two times more abundant in bison pasture than in cattle pasture. Bumble bee species richness was approximately 1.5-2 times greater in prairie, while richness was comparable in the two pasture sites. Habitat-dependent abundance and richness were driven by individual bum-ble bee species habitat preferences. 4. Across habitats, native Monarda fistulosa was highly favoured by foraging bumble bees, particularly by the regionally declining B. auricomus. In the absence of native species , exotic Trifolium pratense and Daucus carota were important forage sources in pastures. 5. These results indicate that grassland management practises to shift grassland plant communities towards native-dominant over exotic-dominant communities may strengthen bumble bee populations, although these effects will likely be Bombus species-dependent. Our findings highlight the need to understand the impacts of habitat on specific bumble bee species, as this will be critical in developing conservation plans for declining populations now and in the future.
... The breadth and persistence of native pollinators is vital to the future of agricultural productivity, biodiversity, and ecosystem services in North America [1][2][3][4]. The processes behind the declines in native pollinators are numerous and include global climate change [5] and habitat conversion [6]. ...
Article
Full-text available
In increasingly urban landscapes, the loss of native pollen and nectar floral resources is impacting ecologically important pollinators. Increased urbanization has also brought about the rise of urban gardens which introduce new floral resources that may help replace those the pollinators have lost. Recently, studies have shown that the microbial communities of nectar may play an important role in plant-pollinator interactions, but these microbial communities and the floral visitors in urban environments are poorly studied. In this study we characterized the floral visitors and nectar microbial communities of Ascelpias curassavica, a non-native tropical milkweed commonly, in an urban environment. We found that the majority of the floral visitors to A. curassavica were honey bees followed closely by monarch butterflies. We also found that there were several unique visitors to each site, such as ants, wasps, solitary bees, several species of butterflies and moths, Anna's hummingbird, and the tarantula hawk wasp. Significant differences in the nectar bacterial alpha and beta diversity were found across the urban sites, although we found no significant differences among the fungal communities. We found that the differences in the bacterial communities were more likely due to the environment and floral visitors rather than physiological differences in the plants growing at the gardens. Greater understanding of the impact of urbanization on the nectar microbiome of urban floral resources and consequently their effect on plant-pollinator relationships will help to predict how these relationships will change with urbanization, and how negative impacts can be mitigated through better management of the floral composition in urban gardens.
... In recent decades, a dramatic decline in both managed and wild bees has caused great attention among agricultural producers and environmentalists because these declines can result in billions of dollars of loss in crop production, and diversity loss of native plant species (Clark, 2017;Hayes and Hansen, 2017). It is now accepted that multiple factors, such as land-use intensification, pesticides, urbanization, invasive alien species, spread of disease and parasites, and climate change, are global threats that individually and synergistically affect the health and development of pollinators (Goulson et al., 2015;Heard et al., 2017;Potts et al., 2010a). ...
... Anthropogenic pressures, including certain management practices, are linked to worldwide insect declines (Sánchez-Bayo and Wyckhuys 2019). Factors triggering pollinator declines have attracted particular attention due to the essential role of pollinators in both natural and managed systems , Potts et al. 2010, Winfree et al. 2009). Although prescription fires are widely viewed as beneficial by managers and policy makers, their effects can be context specific, and idiosyncratic across taxa, guilds, and trophic levels (Freeman et al. 2017). ...
Article
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Controlled burning is an essential tool for restoration and management of Pinus palustris (Longleaf Pine) habitats, yet effects of controlled burning on insect species, including pollinators, are rarely considered in conservation planning. We used blue vane traps to sample native bees (Hymenoptera: Apoidea) at recently burned and unburned sites in 2 Longleaf Pine upland forests in Mississippi and Louisiana. Our objective was to quantify short-term effects of controlled burns given fire-return intervals of 1-2 years are now regularly employed to manage Longleaf Pine woodlands. We sampled during 2016 and 2017 and collected 1777 native bees, representing 43 species. Recent fire was found to have no clear effect on species composition, richness, or community structure. Overall, bee communities from burned and unburned sites were similar. Even the community collected from a site that had remained unburned for 8 years was only marginally different from the others. These results suggest that native bee communities may be resilient to low intensity burns.
... Актуальність дослідження. Дикі бджоли як одні із найкращих запилювачів більшості квіткових рослин останнім часом потерпають від дії багатьох факторів, спричинених діяльністю людини, та катастрофічно скорочують чисельність популяції (Klein et al., 2007, Potts et al., 2010, Smitley, 2018. Ці комахи харчуються нектаром та пилком, вся їхня життєдіяльність пов'язана із квітковими рослинами. ...
... There are reports that some plants have suffered from a general decline in pollinator insects, a phenomenon referred to a pollination crisis [42][43][44] . From the spring season, when A. ginnala flowers, an elevated rate of selfpollination might expect due to the presumable lack of effective pollinators 36 . ...
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Genetic diversity and differentiation are revealed particularly through spatio-temporal environmental heterogeneity. Acer ginnala, as a deciduous shrub/small tree, is a foundation species in many terrestrial ecosystems of Northern China. Owing to its increased use as an economic resource, this species has been in the vulnerability. Therefore, the elucidations of the genetic differentiation and influence of environmental factors on A. ginnala are very critical for its management and future utilization strategies. In this study, high genetic diversity and differentiation occurred in A. ginnala, which might be resulted from its pollination mechanism and species characteristics. Compared with the species level, relatively low genetic diversity was detected at the population level that might be the cause for its vulnerability. There was no significant relationship between genetic and geographical distances, while a significant correlation existed between genetic and environmental distances. Among nineteen climate variables, Annual Mean Temperature (bio1), Mean Diurnal Range (bio2), Isothermality (bio3), Temperature Seasonality (bio4), Precipitation of Wettest Month (bio13), Precipitation Seasonality (bio15), and Precipitation of Warmest Quarter (bio18) could explain the substantial levels of genetic variation (> 40%) in this species. The A. ginnala populations were isolated into multi-subpopulations by the heterogeneous climate conditions, which subsequently promoted the genetic divergence. Climatic heterogeneity played an important role in the pattern of genetic differentiation and population distribution of A. ginnala across a relatively wide range in Northern China. These would provide some clues for the conservation and management of this vulnerable species.
... An alarming decline of insect pollinators' population has been reported globally in the recent years [1][2][3]. The honey bees, among them, are probably the most important species from an ecological and economical aspect [4]. ...
Article
Several negative factors contribute to a decline in the number of insect pollinators. As a novel approach in therapy, we hypothesize that the EM® for bees could potentially have an important therapeutic and immunomodulatory e�ect on honey bee colonies. The aim of our study was to evaluate its impact on honey bees at the individual and colony level. This is the first appliance of the commercial probiotic mix EM® PROBIOTIC FOR BEES in honey bees as economically important social insects. The sugar syrup with 10% of probiotic was administered by spraying or feeding the honey bee colonies in the field conditions, in order to evaluate the infection levels with spores of Nosema spp. and colonies’ strength. Moreover, in laboratory-controlled conditions, in the hoarding cages, adult workers have been fed with sugar syrup supplemented with 2.5, 5, and 10% of EM® for bees for biochemical and immunological analyses of hemolymph, and with 5 and 10% for measuring the size of hypopharyngeal glands. It was found that following the EM® for bees administration the Nosema spp. spore counts in colonies were significantly reduced, and colonies’ strength was increased. The results at the individual level showed significant positive physiological changes in treated groups of adult bees, revealing at the same time a higher mortality rate when feeding sugar syrup supplemented with the probiotic.
... Because foraging bees share certain ecosystems with crop pests, honey bees may be accidently exposed to insecticide sprays. Together with other factors (parasites, diseases, reduced habitats), wide commercialization of neonicotinoids has been blamed for honey bee population decline (Potts et al., 2010;Goulson et al., 2015). With the shift of crop pests from chewing to piercing insects in genetically modified crop systems (Greene et al., 1999;Bergé and Ricroch, 2010;Lu et al., 2008Lu et al., , 2010 and insecticide resistance development (Zhu et al., 2004;Zhu et al., 2012), honey bees and other pollinators face increasing risk of pesticide exposure while foraging. ...
Article
Honey bee is an economically important insect for honey production and pollination. Frequent exposure to toxic pesticides is one of the major risk factors causing the pollinator population decline. However, age effects of honey bees on pesticide susceptibility have been largely ignored and many researchers use bees of unknown age for assessing the risk of pesticides. Honey bee workers are known to go through physiological and behavioral changes in order to differentiate different phenotypes to perform specific duties over their natural lifetime of 6 weeks or longer. In this study, we provide multi-parameter evidences of unignorable age effects of honey bee workers and suggest using a standard bee age to produce reliable and comparable data when assessing variable and realistic situations of in-hive and field exposures to pesticides. Using honey bee workers aged 4- to 42-days old, we examined susceptibility of the bees to five different insecticides from five different classes and measured enzymatic activities of three major detoxification enzymes and an invertase involved in honey production. Results showed gradual increase of natural mortality and decrease of soluble protein content in bees over the age span from 4 days to 42 days. Significant increases of mortality after separate treatments of five different insecticides confirmed drastic age effects of bees over the assessed age span. As they aged, honey bees also showed a gradual increase of cytochrome P450 oxidase activity while still maintaining constant levels of two other detoxification enzymes (esterase and glutathione S-transferase) and an invertase responsible for honey production.
... Currently, the number of insect pollinators is decreasing worldwide (Potts et al., 2010;Biesmeijer et al., 2006;Rhodes, 2018;Thomann et al., 2013;Connelly et al., 2015). About 35% crops directly dependent on pollinators (Klein et al., 2007), with the cost approximately 153 billion euros per year (Gallai et al., 2009). ...
Article
Bumblebees are important for crop pollination. Currently, the number of pollinators is decreasing worldwide, which is attributed mostly to the widespread use of pesticides. The aim of this work was to develop a method for assessing the genotoxicity of pesticides for the Bombus terrestris L. bumblebee using long-range PCR of mitochondrial DNA fragments. We have developed a panel of primers and assessed the genotoxicity of the following pesticides: imidacloprid, rotenone, deltamethrin, difenocanozole, malathion, metribuzin, penconazole, esfenvalerate, and dithianon. All pesticides (except imidacloprid) inhibited mitochondrial respiration fueled by pyruvate + malate; the strongest effect was observed for rotenone and difenocanozole. Three pesticides (dithianon, rotenone, and difenocanozole) affected the rate of H2O2 production. To study the pesticide-induced DNA damage in vitro and in vivo, we used three different mtDNA. The mtDNA damage was observed for all studied pesticides. Most of the studied pesticides caused significant damage to mtDNA in vitro and in vivo when ingested. Our results indicate that all tested pesticides, including herbicides and fungicides, can have a toxic effect on pollinators. However, the extent of pesticide-induced mtDNA damage in the flight muscles was significantly less upon the contact compared to the oral administration.
... Honey bee (Apis mellifera, Apidae) is a managed wildlife species representing a key natural resource for its pollination work in a variety of ecosystems, both wild and agricultural, as well as for honey and wax production. Overall the global number of colonies has increased by 45% since 1961; in the mid-1980s, however, long-term declines and annual losses began in honey bee colonies throughout Europe and the U.S. Colony losses accounted for 25% at the beginning rising to 60% in around 2010 [1,2]. This decline has multiple causes an increasing use of pesticides, changed environmental and socio-economic factors, a series of endemic and new diseases threatening honey bees along with alien parasites are the main causes [3]. ...
Article
Secondary metabolites of bacteria associated with honey bees were evaluated as part of an investigation on their potentiality for apiary health. Low molecular weight compounds released into culture filtrates by the four bacterial isolates taken from surface of healthy honey bees were analyzed using time-of-flight mass spectrometry. Only one low molecular weight compound was found in the culture filtrate of each isolate. Bacillus thuringiensis, Bifidobacterium asteroides and Acetobacteraceae bacterium, released into culture filtrates platynecine, a pyrrolizidine alkaloid of plant origin, which, until now, had never been reported as produced by bacteria. Lactobacillus kunkeei produced a 3,5-dinitropyridine, of unknown biological action never associated so far to bacteria. The highest relative concentration of platynecine was detected in B. thuringiensis (100%), B. asteroides and A. bacterium showed a concentration above 50% and below 25% that concentration. An in vitro assay on the potential for controlling the parasitic mite Varroa destructor by the culture filtrates of the three platynecine-producing bacteria was performed. Varroa mite mortality was proportional to the platynecine relative concentration into culture filtrate. Although miticidal activity of B. thuringiensis might be associated to other toxic proteins produced by this species, B. asteroides toxicity toward V. destructor along with the other findings of this study support the hypothesis that platynecine plays a direct or an indirect role in controlling varroa. Findings of this study suggest that secondary metabolites released by honey bee-associated bacteria represent a source of natural compounds to be considered in the challenge for counteracting the colony decline.
... Administration of antimicrobials triggers changes in the microbiome of humans and livestock, therefore, assessment of the effect of the antimicrobials on bee intestinal microorganisms is important for their health prognosis [23,24,39,40] and a possible explanation of unexpected bee colony deaths [41]. The studies on microbiome diversity and its antimicrobial resistance can provide an overview on nutritional and health problems of honey bees [42]. ...
Article
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The aim of study was to isolate and identify the gut bacteria of Apis mellifera and to evaluate antagonistic effect of the bacteriota against Paenibacillus larvae, which causes American foulbrood (AFB) in honeybees. The dilution plating method was used for the quantification of selected microbial groups from digestive tract of bees, with an emphasis on the bacteriota of the bees' intestines. Bacteria were identified using mass spectrometry (MALDI-TOF-MS Biotyper). Overall, five classes, 27 genera and 66 species of bacteria were identified. Genera Lactobacillus (10 species) and Bacillus (8 species) were the most abundant. Gram-negative bacteria were represented with 16 genera, whereas Gram-positive with 10 genera. Delftia acidovorans and Escherichia coli were the most abundant in the digestive tract of honey bee. Resistance to a selection of antimicrobials was assessed for the bacterial isolates from bee gut and confirmed against all antimicrobials included in the study, with the exception of cefepime. Lactobacillus spp., especially L. kunkeei, L. crispatus and L. acidophilus. showed the strongest antimicrobial activity against P. larvae, the causal pathogen of AFB. Antimicrobial activity of essential oils against isolated bacteria and two isolates of P. larvae were assessed. Application of a broad selection of plant essential oils indicated that Thymus vulgaris had the highest antimicrobial activity against P. larvae.
... The biotic interactions affecting shea tree abundance are influenced by climate change. For instance, studies have suggested that climate change is one of the drivers behind the global decline of pollinators (Potts et al. 2010). However, more studies are needed to fully understand the actual impact of climate change on broader sets of species interacting on complex ecological networks. ...
Article
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Ecosystems degradation, and consequently biodiversity loss, has severe impacts on people around the world. The Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) is one of the international initiatives that have emerged to inform policy makers and aid decisions to prevent further global biodiversity loss, focusing on the interdependence between natural systems and human culture. IPBES promotes the use of scenarios and modelling approaches as a fundamental tool to advance the understanding of the relationships between drivers of change, Nature's Contributions to People (NCP), and social systems. Local-scale case studies with a system approach demonstrating how current knowledge can be used to inform decision-making are still scarce. Here, we present a comprehensive conceptual model and a series of four scenarios under different policies for shea tree species management, as a case-study of applying systems thinking and the NCP concept to a local-scale socio-ecological system. We first characterized the central processes, NCP, drivers and pressures affecting the shea tree system, to investigate the impacts of the multiple uses of the shea tree species on the system as a whole. We then described potential policy options, developed four scenarios, and evaluated them by a Bayesian Belief Network (BBN). We predicted qualitative outcomes of the proposed scenarios: Business-as-usual (BAU), "Conservation and fair trade", "Agroforestry and fair trade" and "Industrial development". We found that the scenarios focussing on conservation, fair trade and agroforestry, can improve the conservation status of shea trees, and enhance wellbeing in the local communities. In this case study, we demonstrate that the development of a comprehensive conceptual model at a local scale can be a useful exercise to identify opportunities for effective policy strategies and social innovation. The shea tree case study can provide an example for modelling non-timber forest products in other regions around the world that face similar drivers and pressures. Species for which this model could be adapted include Central and South American species such as the Brazilian nut (Bertholletia excelsa), cocoa (Theobroma cacao), andiroba (Carapa guianensis), açai (Euterpe oleracea) and the wax palm (Ceroxylon quindiuense). The model and workflow applied here may thus be used to understand similar socio-ecological systems with local and international economic value across the Neotropical region. Modelagem de cenários para o manejo sustentável de produtos florestais não-madeireiros em ecossistemas tropicais Resumo: A degradação dos ecossistemas e sua consequente perda de biodiversidade apresentam graves impactos sobre as pessoas em todo o mundo. A Plataforma Intergovernamental de Biodiversidade e Serviços Ecossistêmicos (IPBES) é uma das iniciativas internacionais que surgiram para informar tomadores de decisão e o desenvolvimento de políticas para evitar mais perdas globais de biodiversidade, com foco na interdependência entre sistemas naturais e a cultura humana. O IPBES promove o uso de cenários futuros e abordagens de modelagem como uma ferramenta fundamental para avançar no entendimento das relações entre fatores motivadores de mudança (vetores), as Contribuições da Natureza para as Pessoas (NCP) e sistemas sociais. Estudos de caso em escala local com uma abordagem de sistemas mostrando como o conhecimento atual pode ser usado para informar a tomada de decisão ainda são poucos. Neste trabalho, apresentamos um modelo conceitual abrangente e um conjunto de quatro cenários sob diferentes políticas para o manejo da árvore de karité, como estudo de caso para a aplicação de uma abordagem de sistemas e do conceito de NCP em um sistema socioecológico em escala local. Primeiro nós caracterizamos os processos centrais, os NCP, e os vetores e pressões que afetam o sistema da árvore de karité, para então, investigar os impactos dos múltiplos usos da espécie no sistema como um todo. Em seguida, descrevemos opções de políticas possíveis, a partir das quais desenvolvemos quatro cenários e os avaliamos por Redes Bayesianas baseadas em Crenças (BBN). Nós avaliamos os resultados qualitativos dos quatro cenários de manejo propostos: "business-as-usual" (BAU), "Conservação e Fair Trade", "Agrofloresta e Fair Trade", e "Desenvolvimento Agroindustrial". Verificamos que os cenários que incluíam medidas de conservação e comércio justo, assim como o que previa práticas agroflorestais indicaram potenciais melhorias no status de conservação das árvores de karité e aprimoramento do bem-estar das comunidades locais. Neste estudo de caso, demonstramos que o desenvolvimento de um modelo conceitual mais completo na escala local pode ser útil na identificação de oportunidades para a proposição de estratégias políticas efetivas e inovação social. O estudo de caso da árvore de karité pode fornecer um exemplo de modelagem de produtos florestais não-madeireiros para outras regiões do mundo que enfrentam vetores de mudança e pressões semelhantes. As espécies para as quais esse modelo pode ser adaptado incluem espécies da América Central e do Sul, como a castanha-do-brasil (Bertholletia excelsa), cacau (Theobroma cacao), andiroba (Carapa guianensis), açaí (Euterpe oleracea) e a palma da cera (Ceroxylon quindiuense). O modelo e a proposta de trabalho aplicados aqui podem, portanto, ser usados para entender sistemas socio-ecológicos semelhantes com espécies de valor econômico local e internacional em toda a região neotropical.
... Pollinators are declining worldwide mainly due to agriculture intensification and habitat loss (Potts et al., 2010;Roulston & Goodell, 2011;Hallmann et al., 2017), while 87.5% of flowering plant species worldwide depend on them to ensure their sexual reproduction (Ollerton et al., 2011). However, knowledge about pollinator decline differs among taxa (Hallmann Correspondence: Jérémie Goulnik, Université de Lorraine, INRAE, LAE, F-54000 Nancy, France. ...
Article
1. Consequences of a decline in pollination function in semi‐natural ecosystems are largely unknown due to variability in pollinator effectiveness, that is, their contribution to pollen deposition alone. While pollination effectiveness has been shown to be related to body size and hairiness of pollinators for some crops, studies encompassing a wide diversity of pollinators interacting with wild plant communities are lacking. 2. Thus, the relationships between pollen load, which is a measurement of pollen transport ability and a proxy of pollinator effectiveness, and morphological traits of pollinators sampled in 16 grasslands in Moselle, France, were investigated. The area, hairiness, and pollen load of each pollinator's face were measured for 658 individuals from 127 bee and fly species interacting with 36 wild plant species. Pollinator dry mass was also measured on 543 individuals from 109 species. 3. Dry body mass and facial area of pollinators were positively linked. This study highlights that bees transported significantly more pollen grains on their face than flies. Furthermore, bees' faces were larger and hairier. We also found that pollinators' facial pollen load increased with facial area and hairiness when we considered all pollinators. However, hairiness is not significant within pollinator group (bees or flies), mirroring a potential phylogenetic signal. 4. Hence, this study shows a wide diversity of pollinator and plant species in which larger and hairier pollinators may transport more pollen grains, at least on their face. However, future studies involving other pollinator body parts are needed to generalise these relationships.
... Bees have been extensively studied and systematically documented around the worldand are generally recognized to be seriously threatened. However, in some areas, such as the tropics of the Americas, more research is still needed on the conservation status of bees (Biesmeijer 2006;Potts et al. 2010Potts et al. , 2016. ...
Article
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Local ecological knowledge (LEK) is of utmost importance for biodiversity conservation; however, a number of studies document the loss of LEK regarding native bees. Stingless bees (Apidae: Meliponini) are important pollinators that have been managed by humans in all tropical areas of the world. Our work documents the decline of Meliponini and associated LEK in the state of Michoacán, western Mexico, as well as local historical management and perceptions of the diversity and abundance of bees. Through ecological sampling, semi-structured interviews, and participant observation, we established the presence of 13 species of Meliponini and recognition of 23 local names. Although stingless bees’ pot-honey is harvested directly through extraction of wild nests, local knowledge about bee diversity, behavior, and use can contribute to their conservation. Because of recent access to manufactured products and the scarcity of wild nests, LEK and pot-honey harvest are being abandoned and forgotten in some areas. Maintaining LEK is important in designing sustainable use strategies to prevent the extinction of wild nests and allow conservation of bees as well as the cultural legacy associated with them, essential in the context of a global decline of pollinators.
... Although less studied, regulating services will also be affected. For example, climate change is, among other factors, implicated in global declines of wild pollinators and changes in abundance in some areas (IPBES, 2016;Potts et al., 2010). This will result in reduced reproduction of insect-pollinated crops and fruits, but also wild plant species important for other organisms or valued by rural communities. ...
Article
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Land reform is an important socio-political strategy in many countries. Despite the importance of ecosystem health in attaining land reform objectives, human-nature interactions have been largely absent from contemporary land reform discussions. In this perspectives paper, we highlight why land reform programmes could benefit from considering ecosystem services in their planning processes, to better achieve their goals of socio-economic development and equity. Drawing on examples from South Africa, we argue that an ecosystem services lens can help achieve equity in land reform programmes by providing insight into how land-use legacies and the multi-functional nature of landscapes influence who benefits from land reform across space and through time. An ecosystem services lens also broadens understanding of how fragmentation and a changing climate may affect land reform benefits over time. In ignoring these human-nature interactions, and often unquestioningly applying one-size-fit-all approaches, land-reform policies risk missing the ultimate needs of beneficiaries and broader society. Considering these insights, we discuss practical implications of an ecosystem services lens for land reform programmes. These include the need for context-sensitive, localized land reform planning that accounts for ecosystem service heterogeneity, possible trade-offs, and beneficiaries’ preferences and capacities. Accordingly, extension services need to possess local knowledge and avoid generic, top-down and inflexible approaches. These social-ecological considerations are imperative if countries are to achieve sustainable and equitable land reform.
... Applcation of essential oils from these arboreal invasive plants agains pests and weeds can help to reduce the use the of synthetic pesticides which are known with their negative effects on the wild bees and honeybees (Potts et al. 2010, Goulson et al. 2013. However further research is necessary to test the effect of these essential oils on the pollinators. ...
Article
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The high tolerance of various habitat conditions and potent propagation ability of Ailanthus altissima (Mill.) Swingle (Simaroubaceae) and Amorpha fruticosa L. (Fabaceae) promote their aggressive invasive behaviour. Additionally, they not only over-compete the local vegetation but suppress the seed development. In the newly invaded habitats they might not have suitable herbivores to control their populations. The aim of this review is to evaluate the potential of A. altissima and A. fruticosa , as cheap sources of valuable essential oils. The essential oils yield and compostion of both plant species vary significantly depending on plant parts, origin and time of collection. The main constituents of A. altissima essential oil are α-curcumene, α-gurjunene, γ-cadinene, α-humulene β-caryophyllene caryophyllene oxide, germacrene D etc. The main constituents of A. fruticosa are δ-cadinene, γ-cadinene, β-caryophyllene γ-muurolene +, ar-curcumene, myrcene etc. These essential oils have been reported to possess different activities such as antimicrobial, insect repellent, insecticidal and herbicidal activity. Due to the fact that these are aggressive invasive species, they can provide abundant and cheap resources. Additionally, future industrial exploitation of the biomass of these invasive plants for essential oils’ extraction might contribute to biodiversity conservation by relieving their destructive impact on the natural habitats.
... Pollinators and natural enemies provide critical ecosystem services to agriculture through pollination and biological pest control. Numerous factors can contribute to beneficial insect declines, including climate change, pests and diseases, pesticide use, and decreasing food and habitat resources (Goulson et al. 2008;Brown and Paxton 2009;Winfree et al. 2009;Potts et al. 2010). Wild bees and natural enemies that inhabit agroecosystems need food and shelter throughout the growing season, and habitat management is a conservation strategy that aims to enhance the quality of food and shelter resources for beneficial insects within an agroecosystem (Landis et al. 2000). ...
Article
Pollination and pest control are important in many agroecosystems. Beneficial insects that provide these services (e.g. bees and natural enemies) often require floral resources beyond crop bloom. Planting floral resources along crop field margins may be a useful tactic to support communities of beneficial insects in agroecosystems. We examined the effect of planting buckwheat (Fagopyrum esculentum Moench) along lowbush blueberry (Vaccinium angustifolium Aiton) field margins on beneficial insect abundance and species richness. We found that bee abundance was higher in buckwheat transects than control transects in 2014 and 2015, but not 2016, and that bee species richness was higher in buckwheat transects than in control transects in 2015 only. High variability occurred across years. All bee genera recorded during blueberry bloom were also collected in buckwheat transects, suggesting buckwheat is a useful resource for bee community involved in blueberry pollination. The effect of buckwheat on natural enemies was variable and inconsistent. We conclude buckwheat influenced bee and natural enemy communities during certain years, but field edges in the lowbush blueberry fields studied may already adequately support beneficial insects. Thus, not all habitat management efforts with augmentative floral plantings may consistently boost communities of beneficial insects.
... With the current global pollinator decline and its impact on crop productivity (Gallai et al., 2009;Potts et al., 2010), knowledge of which pollinators visit a particular crop is becoming a priority (Aizen et al., 2008;Garibaldi et al., 2014). Approximately 70% of crops globally rely on pollinators (Klein et al., 2007) and, although the honey bee is economically the most valuable of all, pollination by other bees (including bumble bees and solitary bees), non-bee insects and vertebrates contributes considerably to crop pollination (Garibaldi et al., 2013;Rader et al., 2016). ...
Article
Enabling food security requires access to a broad range of genetic resources to facilitate crop breeding. This need is increased in a climate change scenario, which will require the production of novel crops adapted to new conditions. However, many major crops have reduced genetic diversity due to the genetic bottlenecks that they have experienced during their domestication and subsequent breeding. Crop wild relatives (CWRs) remain underexploited in plant breeding programmes, mostly because of the lack of knowledge of their cross-compatibility with crops. In this study, we use a combination of phylogenetic distance metrics, cytogenetic compatibility data (e.g. chromosome number and ploidy) and information about breeding systems to predict interspecific cross-compatibility between crop and wild species and hence identify crop wild phylorelatives (CWPs) (i.e. CWRs that can breed with the crop). We illustrate this concept using cultivated asparagus as a model by integrating previous cross-compatibility knowledge and CWR classifications into a phylogenetic framework reconstructed using available sequence data. Our approach aims to reinforce the use of the gene pool classification system of CWRs of Harlan and De Wet, since CWPs are estimated to belong to the secondary gene pool and non-CWPs to the tertiary gene pool. Identifying CWPs unlocks novel uses of genetic resources, although such data are available for less than half of the known CWRs (43.4% with sequence data and 32.5% with known ploidy). The need to conserve plants that provide or enhance provisioning ecosystem services, including CWRs, is clear if we are to rise to the global challenge of ensuring food security for all. However, basic knowledge about their conservation status is still lacking, with only c. 20% of CWRs assigned an IUCN red list assessment, 23% of which are Data Deficient (DD). Using the CWP classification presented here to define CWRs will contribute towards helping to prioritize CWRs for IUCN assessments and, where prioritised, conservation. ADDITIONAL KEYWORDS: Asparagus-chromosome-plant breeding-reproductive biology.
... A decline of almost half of insect species has been recorded since, few decades and some are at verge of extinction, food production methods should be changed to save rich diversity, and otherwise these would be at peril of extermination in succeeding few years [8]. This loss is a threat toward food security and a leading cause of economic instability globally [13,14]. The decline of pollinators; globally Anthropogenic activities are major concerns regarding biodiversity decline of ecologically important species of insects [15,16]. ...
... However, in the field plot that was planted, surrounded, and intercalated with Heliaunthus annuuss (season 2016), Apis spp were not found either in the samples collected. The effect of Colony Collapse Disorder and the global decline in pollinators reported (Potts et al. 2010) appears to have an effect on the Panhandle area of Nebraska. ...
Article
Phaseolus vulgaris, or dry beans, are generally cultivated for their seeds, which add flavor to the diets of millions of people throughout the world. This crop was originally domesticated in South America more than 7,000 years ago, eventually spreading north through Mexico and across most of the United States (NDBGA, n.d.). Phaseolus vulgaris belongs to the legume family, and like other legumes it can fix nitrogen in the soil from the air through a symbiotic relationship with a bacterium called Rhizobia. In addition to this, P. vulgaris is high in protein, and in many parts of the world, it is considered the cheapest way to acquire protein (Plants of the World Online, n.d.). In Nebraska, dry bean producers plant around 140,000 to 200,000 acres of beans annually, producing approximately 1 billion servings for human consumption. The production is concentrated in Western Nebraska where the climate is arid, and the warm days and cool nights provide excellent growing conditions for dry, edible beans. The state of Nebraska produces a greater amount of northern beans than any other state in the nation, is second in pinto and light red kidney production, and fourth in black bean production (Ostdiek, 2018). Insect pollinators provide critical ecosystem services to many fruit, vegetable, and field crops that depend on pollination for fruit and seed production (Gill & O’Neal, 2015). Phaseolus vulgaris is a self-pollinating crop, and therefore does not require any pollinator agents for its reproduction. However, it is thought that flowers attract pollinators. Due to past research in crops from Phaseolus spp. and observations of pollinators in dry bean fields, it is believed that they increase yield and seed quality. Previous research papers such as Du Preez et al. (1975), and recent papers such as Kingha et al. (2012) and Doukal et al. (2013) confirmed that Hymenopterans are related to the increased of yield, size, and seed quality of Phaseolus spp. crops. They also recommended the planting of dry bean fields close to bee hives or nests to improve pod and seed production. Therefore, the conservation of pollinators such as Hymenopterans and a better understanding of pesticide application on fields are important. Lastly, the improvement of yield in the crop is essential to meet the demand in world nutrition. The objectives of this study are to describe the pollinator community within dry bean fields, gain insight of pollinator taxa that may contact dry bean pollen, and verify if they affect yield and seed quality of the plant.
... Parasites and disease can cause harm to social and solitary bees [40][41][42]. Of the many risk factors, the loss of native habitats, especially when the loss is caused by urban development and to an even greater extent, agricultural intensification, stands out among risk factors as one of the most detrimental to bee populations [43][44][45]. ...
Article
Solitary bees and other wild pollinators provide an important ecosystem service which can benefit both the agricultural economy and the sustainability of many native ecosystems. Many solitary bees, however, are experiencing decreases in their populations and ranges, resulting in an overall loss of pollinator species richness in many areas. Several interacting factors have been implicated in this decline, including increased pesticide use, climate change, and pathogens, but habitat loss remains one of the primary drivers. The widespread conversion of natural habitats into agricultural landscapes has decreased the availability of adequate nesting sites and floral diversity for many bee species. Large monocultures with intensive production systems often cannot support the populations of wild bees (particularly species with short foraging ranges) necessary to ensure adequate pollination of animal-pollinated crops. Diversifying agricultural landscapes through the incorporation of wildflower plantings, as well as the preservation of remaining natural habitats, may offer a solution, as it has been shown to increase both bee diversity and abundance and the pollination of nearby crops. In this review article, we discuss the various effects of habitat loss on solitary bees and different ways to mitigate such effects in order to conserve bee diversity and populations in agricultural landscapes.
... There is extensive evidence of a decline in pollinators around the world, with habitat fragmentation/loss and climate change as the main causes of this decline (Potts et al., 2010). Climate change can affect bees on different levels, such as behavior, physiology, quality of the floral environment, population dynamics, and the emergence of new interactions between species and parasites and pathogens (Le Conte & Navajas, 2008). ...
Article
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Aim The objective of this study is to estimate the current potential geographic distribution of Plebeia flavocincta and to evaluate the influence of climate on the dynamics of suitable habitat availability in the past and in the future. Location Northeast region of Brazil and dry forest areas. Methods The habitat suitability modeling was based on two algorithms, two global circulation models, and six different scenarios. We used this tool to estimate the areas of occurrence in the past (Last Interglacial and Last Glacial Maximum), in the present, and in the future (years 2050 and 2070). Results According to the models, P. flavocincta had great dynamics in the availability of suitable habitats with periods of retraction and expansion of these areas in the past. Our results suggest that this taxon may benefit in terms of climate suitability gain in Northeast Brazil in the future. In addition, we identified high‐altitude areas and the eastern coast as climatically stable. Conclusion The information provided can be used by decision makers to support actions toward protecting and sustainably managing this taxon. Protection measures for this taxon are particularly important because this insect contributes to the local flora and, although our results indicate that the climate may favor this taxon, other factors can negatively affect it, such as high levels of habitat loss due to anthropogenic activities.
... Honeybees are of proven importance for the agricultural economy and the conservation of biodiversity [1], as given by their global distribution and generalist foraging behavior. Honeybees can be considered the most important single pollinator species of a wide variety of wild flora, livestock pastures, and private gardens [2,3]. ...
Article
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It is well known that factors acting on the decrease of population of honeybees, can act on the male and female reproductive system, compromising the fertility of queens and drones. While there are many studies on female fertility, only a few studies have focused on male fertility and the possible alterations of the reproductive system. The testes of 25 samples of adult drones of Apis mellifera ligustica were analyzed by histopathology using an innovative histological processing technique and the alterations that were found are here described. Most of the samples showed unaltered testes but, in some cases, samples showed degenerated seminiferous tubules, while others appeared immature. Although a limited number of samples were analyzed, the results obtained displayed that histopathological alterations of the testes exist also in honeybees and that more interest should be put to the matter, as honeybees could be considered as bioindicators for endocrine disruptors. Future studies on a larger number of samples are necessary to analyze how different environmental factors can act and induce alterations in the honeybee reproductive system.
... Honey bees, important pollinators, have been demonstrated to be capable of increasing yield in 96% of animal-pollinated crops, creating a value of 212 billion dollars annually [1,2]. However, feral and managed honey bee colony losses consistently maintained a very high level worldwide in recent years, and substantial concerns have been raised about the future availability of honey bee pollination services [3]. ...
Article
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Surveys of managed honey bee colony losses worldwide have become fundamental for engineering a sustainable and systematic approach to protect honey bees. Though China is a member of the world’s apiculture superpowers, the investigation of honey bee colony losses from Chinese government was not formally launched until recently. In this study, we investigated the colony winter losses of the western honey bee (Apis mellifera) of four consecutive years in 2013–2017 from 19 provinces in China, with a total of 2387 responding Chinese beekeepers (195 hobby beekeepers, 1789 side-line beekeepers, 403 commercial beekeepers) providing the records of overwintering mortality of honey bee colonies. The calculated colony losses were 8.7%, a relatively low mortality below the world average. There still exist considerable variations in total losses among provinces (ranging from 0.9% to 22.0%), years (ranging from 8.1% to 10.6%) and scales of apiaries (ranging from 7.5% to 10.0%). Furthermore, we deeply analyzed and estimated the effects of potential risk factors on the colonies’ winter losses, and speculated that the queen problems, the operation sizes and proportion of new queens are leading causes of the high honey bee colony mortality in China. More research and advanced technical methods are still required for correlation analysis and verification in future surveys of managed honey bee colony winter losses.
... Insect pollinators are estimated to support 9.5% of world food production (Gallai et al., 2009) and wild bees have an important role in the delivery of this ecosystem service (Garibaldi, 2013). However, wild bees have undergone global declines (Woodcock et al., 2016) that have been linked to habitat loss and fragmentation, pathogens (Camerona et al., 2016), climate change and insecticides (Biesmeijer, 2006;Ollerton et al., 2014;Potts, 2010;Winfree et al., 2009). Habitat degradations lead to severe decrease of bee abundance and richness in isolated semi-natural habitats (Krewenka et al., 2011). ...
Preprint
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The investigations on value of various landscapes categories as a foraging habitat for wild bees were carried out in mosaics of small scale agriculture and natural vegetation areas of Kashmir valley during the spring seasons of year 2013 and 2014. In present study we tested the importance of habitat area, landscape composition and configuration on wild bees in valley. The habitats selected were hedgerows, agricultural fields, grasslands, and native woodland. We observed that bee differ in their response to many factors of landscapes. The hedgerows were attractive foraging habitat for native bees. The total species richness was highest in hedgerows. The overall bee faunas overlapped among habitats, bee assemblages in hedgerows were more similar to those in fields than to those woodlands. The flowering shrubs were important in attracting bees. Species richness and abundance of wild bees were surveyed on with independent gradients in local and landscape factors. Total wild bee richness was positively affected by complex landscape configuration, large habitat area and high habitat quality which provide them with assured nesting sites.
... contains supplementary material, which is available to authorized users. bee decline (Biesmeijer et al. 2006;Potts et al. 2010;Bystriakova et al. 2018), widespread ecological and economic interest is being shown in preserving pollination services in agroecosystems (Chopra et al. 2015;Melathopoulos et al. 2015). The conservation of semi-natural habitats (Banaszak 1992;Albrecht et al. 2007) and the establishment of novel habitats such as flower strips (Scheper et al. 2013(Scheper et al. , 2015Blaauw and Isaacs 2014) have been shown to be successful for the promotion of wild bee communities and consequently for their pollination services. ...
Article
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ContextLandscape and local habitat traits moderate wild bee communities. However, whether landscape effects differ between local habitat types is largely unknown.Objectives We explored the way that wild bee communities in three distinct habitats are shaped by landscape composition and the availability of flowering plants by evaluating divergences in response patterns between habitats.Methods In a large-scale monitoring project across 20 research areas, wild bee data were collected on three habitats: near-natural grassland, established flower plantings and residual habitats (e.g. field margins). Additionally, landscape composition was mapped around the research areas.ResultsOur monitoring produced a dataset of 27,650 bees belonging to 324 species. Bee communities on all three habitats reacted similarly to local flower availability. Intensively managed grassland in the surrounding landscape had an overall negative effect on the studied habitats. Other landscape variables produced diverging response patterns that were particularly pronounced during early and late season. Bee communities in near-natural grassland showed a strong positive response to ruderal areas. Flower plantings and residual habitats such as field margins showed a pronounced positive response to extensively managed grassland and woodland edges. Response patterns regarding bee abundance were consistent with those found for species richness.Conclusion We advise the consideration of local habitat type and seasonality when assessing the effect of landscape context on bee communities. A reduction in the intensity of grassland management enhances bee diversity in a broad range of habitats. Moreover, wild bee communities are promoted by habitat types such as ruderal areas or woodland edges.
... Principaux mécanismes affectant les communautés de pollinisateurs dans les agroécosystèmesOutre les effets du paysage, la structure et la composition des communautés de pollinisateurs dépendent de nombreuses autres variables environnementales. Dans les agroécosystèmes, les pratiques agricoles sont une variable centrale modelant ces communautés, mais ces dernières sont également les résultats du climat, des interactions avec d'autres espèces, etc. Plusieurs synthèses des facteurs influençant les pollinisateurs sont disponibles, par exemplePotts et al. (2010) ouVanbergen et al. (2013). Ces mécanismes sont susceptibles d'interagir entre eux, leur interaction pouvant amplifier les effets individuels.Certaines pratiques agricoles ont des effets négatifs marqués sur la diversité ou l'abondance des communautés de pollinisateurs. ...
... These issues combined with the importance of insects for maintaining and monitoring protected areas (Foster 1993, Nervo et al. 2017Wills & Landis 2018), sustaining Africa's booming human population (either as a direct source of food (Gahukar 2011), or indirectly as a food producer through pollination or soil turnover (Rodger et al. 2004)), leave entomology as a serious gap in conservation research that requires urgent attention. Insects themselves have drastically declined worldwide in recent decades (Alstad et al. 1989, Hallmann et al. 2017, leading to worldwide concern and alarm amongst scientists as to the fate of all global natural systems that are largely reliant 46 on insects (Potts et al. 2010, Rader et al. 2016. In contrast to the time and funding needed to survey charismatic large mammals (Oliver & Beattie 1996, Jones & Eggleton 2000, insects can be easily and cheaply surveyed and generate a significant amount of data and information about the surrounding environment for each survey effort, ...
Research
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ABSTRACT The Lilongwe Wildlife Trust and Conservation Research Africa are the first to conduct long-term research projects in Vwaza Marsh Wildlife Reserve (VMWR). These projects focus on large mammals, elephants, primates, bats and insects, and aim to identify and monitor biodiversity and long-term trends in VMWR. Habitats are under increasing pressure from climate change and wildlife populations are at risk from many anthropogenic threats, such as poaching and deforestation. Biosphere Expeditions citizen scientists supported these research projects for the first time in 2018. Field work was conducted between 2 September and 19 October 2018 in three two-week long groups comprising twelve citizen scientists per group from Austria, Canada, China, France, Germany, Malaysia, Switzerland, the UK and USA. The inaugural expedition was a success and a showcase on how citizen science can provide resources and critical data gathering abilities to important wildlife studies. It is the intention of all partners to continue the successful partnership. Large mammal surveys Camera trapping was the most successful large mammal survey method, recording the highest species diversity (36 species) and more than 3,300 images. The surveys provided the first ever images of lion in the VMWR, known to be present but previously never recorded on camera. Other rarely seen carnivores were also recorded including serval, caracal and leopard. Large mammal transect (LMT) surveys were less successful than camera trapping surveys in detecting mammal presence and diversity. LMTs yielded twelve species, with baboons being most frequently encountered. Species of note were roan antelope, which are rarely sighted, and puku, as they are classified as Near Threatened (IUCN). Surveys of hippo populations inhabiting Lake Kazuni in the south of the reserve were very successful, yielding an average 147 hippos per transect, which demonstrates a healthy population for the area. Elephants were observed mostly at the lake and river in front of the expedition base camp and along the lakeshore. The expedition augmented the existing identification database by 20%. Results indicate high large mammal species diversity in VMWR. Five of the species recorded by the expedition are classed as Vulnerable and one species (puku) as Near Threatened by IUCN. Results provide an important baseline for future monitoring of large mammal populations in the VMWR. Future expeditions will be augment these data and conduct more robust analyses of populations, including estimates of population density to facilitate effective management of large mammals in the park. Bat and insect monitoring Bat species and abundances were assessed at spatially independent survey sites using standardized biodiversity monitoring surveys, across two habitat types: floodplain and woodland. A total of 17 bat surveys were completed, at 17 sites, resulting in 5,519 trapping meter survey hours. Bat surveys were successful with 62 bats captured representing six species and one species group. Chaerephon pumilus dominated the species composition despite only being recorded in woodland. Neoromicia nana was the most common species. This runs in accordance with other studies in Africa. as this is generalist species occupying a range of habitat types. Captures of Pipistrellus rueppellii are of particular interest as this species has rarely been captured by African Bat Conservation in the previous five years. This may suggest that the species has a limited distribution in VMWR, however, this can only be confirmed by additional surveys and thereby greatly increased sample size. Insect species diversity and abundances were assessed as part of the standardised biodiversity monitoring surveys at spatially independent sites, alongside bat surveys. They were also assessed opportunistically at random sites using three butterfly traps, ten pitfall traps and one Heath light trap. A total of six standardised biodiversity monitoring surveys, and four opportunistic surveys were conducted. There was a wide representation of insect orders from the biodiversity monitoring surveys, with ten orders recorded. Coleoptera and Lepidoptera contained the highest abundances of individuals. Orders such as Mantodea, Trichoptera and Orthoptera occurred in much smaller abundances in general, and were absent completely from some surveys. Even though a small number of opportunistic insect surveys were conducted over a short period of six weeks, a substantial insect diversity was apparent, with 68 morpho-species recorded, representing nine orders. Lepidoptera, Coleoptera and Hymenoptera were the most diverse. The opportunistic discovery of an Embioptera individual is a significant addition to the insect diversity of VMWR. Although these results are based on a small sample size, they do show quite a variation in abundances and presence of orders overall. Continued monitoring of insect populations alongside bat populations will allow us to monitor any trends and any effect that these variations may have on the insectivorous bat populations of VMWR, across seasons and habitats. Primate behaviour Two baboon troops were observed by the expedition participants with most data collected from one troop that occupied the area around the Department of National Parks and Wildlife staff village. The staff village provides a number of benefits for baboons, including access to nutritious human-foods (e.g. nsima, maize) and increased protection from predators. Data collected provide a baseline for further research and provide a framework for developing future studies on baboons. Future expeditions will include habituation of the baboon troops in VMWR to facilitate research on behavioural ecology and ranging patterns. These data will be used for future genetic work to assess the possible hybridisation zone of yellow and kinda baboon species of the VMWR. CHIYAMBI Lilongwe Wildlife Trust komanso Conservation Research Africa kwa nthawi yoyamba m`mbiri ya dziko lino ikhazikitsa ntchito yakafukufuku yomwe ichitike kwa nthawi yayitali kwambiri m`nkhalango yotetezedwa ya Vwaza Marsh Wildlife Reserve (VMWR). Kafukufukuyu akhudza kwambiri nyama zikuluzikulu monga Njobvu, Anyani amitundu yosiyanasiyana, mileme ndi zinthu zina zamoyo zing`ono zing`ono zowuluka, ndicholinga chofuna kudziwa zambiri za moyo wa zachilengedwezi komanso m`mene izo zimadzithandizira kuti zikhale ndi moyo kwa nthawi yaitali. Nkhani yodziwikiratu ndiyakuti malo amene zachilengedwezi zimakhala ali pachiopsezo kamba kakusintha kwa nyengo. Moyo wa nyama komaso zomerazi ulinso pachiopsezo kamba ka kamchitidwe owononga chilengedwe omwe anthu akupanga monga kupha nyama zakuthengo ndi kudula mitengo mwachisawawa. Bungwe la Biosphere Expeditions lidzapeza njira zina zatsopano komaso zosatira zopezaka kuchokera kafukufukuyu zidzagwiritsidwa ntchito ngati poyambira pakawuniwuni wa zachilengedwe m`nkhalango ya VMWR. Zotsatirazi za zomwe zidzapezeke zidzanthandiza kupereka chinthuzithuzi cha kuchulukuka kwa nyama mu nkhalango ya VMWR kwa nthawi yayitali. Bungwe lalikulu pa dziko lonse lapansi lotchedwa Biosphere Expeditions lomwe limadziwika bwino ndi ntchito yakafukufuku wa zinthu za moyo pogwiritsa ntchito njira za sayansi lidalowa nawo m`gulu la mabungwe ogwira ntchitoyi koyamba m`mbiri ya dziko lino mchaka cha 2008. Ntchito yoyamba yobweretsa zotsatira zakafukufukufuku woyambilira kuchokera m`madera okhudzidwa, idachitika kwa masabata awiri kuyambira pa 2 Sepitembala kufika tsiku la 19 Okutobala chaka cha 2018.Ntchitoyi idagwiridwa ndi akatswiri azasayansi nkhumi ndi awiri wochokera m`maiko monga: Austria, Canada, China, France, Germany, Malaysia, Switzerland, UK ndi USA. Cholinga chakafukufukuwu chidali chofuna kupeza zotsatira zochuluka zomwe zingathandizire kuti kafufuku otsatira akhale ndi zinthu zonse zofunika. Zotsatira zochokera ku kafukufuku oyamba zidasonyeza kuti m`nkhalango yotetezedwa ya VMWR muli zinthu zachilengedwe zosiyanasiyana monga nyama. Nyamazi ndi monga mikango komanso nyama zina zomwe zimadya nyama zinzake, ndipo nyamazi zidajambulidwa nthawi yomwe ntchitoyi imagwiridwa. Chiwerengero cha nyama monga njobvu ndi mvuu chidaonetsanso kuti chinali chokwera kuphatikizapo nyama zosiyanasiyana, kusonyeza kuti chilengedwe chidakali bwino ndithu. Kafukufuku oyambilirayo adasonyezanso kufunika kwa mitsinje ikuluikulu polimbikitsa kupezeka kwa zinthu zamoyo zosiyanasiyana mchigawo chakumpoto kwa dziko lino. Ndipo kupitiliza kafukufukuyu kuthandiza kumvetsesa kwa kufunika kwa zachilengedwe komanso kuchuluka kwake m`nkhalango yotetezedwa ya VMWR. Kafukufukuyi athandiziraso kumvetsesa kwa kufunika kwa malo abwino okhala zinthu zamoyo zosiyanasiyana ndi kudalirana pakati pa zamoyozi. CHIYAMBI Lilongwe Wildlife Trust kweniso Conservation Research Africa kwa nyengo yakwamba mu mbiri ya chalo chithu cha Malawi yakhazikiska ntchito yakafukufuku iyo ichitikenge kwa nyengo yitali chomene m`thengere lakuvikililika la Vwaza Marsh Wildlife Reserve (VMWR). Kafukufuku uyu wakhwaskenge chomene nyama zikuluzikulu nga zovu, bamunkhwere bakupambanapambana, bakasuska, na vinthu vinyake vyamoyo vidokovidoko ivyo vikuduka m`chanya, nachakulinga chakukhumba kumanya vinandi vakukhwaska moyo wa vyachilengiwa kweniso umo ivyo vikujiwovwilirira kuti vikhale na moyo kwa nyengo yitali. Nkhani yakumanyikirathu njakuti malo awo vyachilengiwa ivi vikukhala ngawemi chala chifukwa cha kusintha kwa nyengo. Nabo umoyo wa nyama zamthengere kweniso makuni nguwemi chala chifukwa cha nkhalo yabanthu abo bakukoma nyama nakudumula makuni mwambula kupwelerera chala. Bungwe la Biosphere Expeditions lilikusanga nthowa zinyake zasono kufumira kuvipambi vyakukafukufuku wakwambilira izo zikoleskekenge ntchito mukafukufuku wasono.Vipambi vya kafukufuku wasono vizamuwovwira chomene pakuona kuti nyama nizinandi uli mu nthengere lakuvikilililka la VMWR kwa nyengo yitali chomene. Bungwe lakumanyikwa makola pa chalo chonse cha pasi la Biosphere Expeditions ilo likumanyikwa makola na ntchito yakafukufuku wa vinthu vya moyo pakukoleska ntchito nthowa za sayansi likanjira nabo m`gulu la mabungwe awo bakugwira ntchito iyi kakwamba mu mbiri ya chalo chithu cha Malawi mchaka cha 2008. Ntchito yakwamba yakwiziska vipambi vyakafukufukufuku wakwambilira kufumira m`mizi yakukhwaskika, ikachitika kwa masabata babiri kuyambira pa 2 Seputembala kufika pa dazi la 19 Okutobala chaka cha 2018.Ntchito iyi ikagwirika na nkhwantha zasayansi zakukwana 12 kufumira m`vyalo nga: Austria, Canada, China, France, Germany, Malaysia, Switzerland, UK na USA.Chakulinga chakafukufuku uyu chikaba chakukhumba kusanga vinthu vinandi ivyo vingawovwira ku kafufuku uyu wapangikenge sono. Vipambi vyakufumira ku kafukufuku wakwamba vilikuoneska kuti mthengere la kuvikililika la VMWR muli vinthu vyachilengiwa vyakupambanapambana nga nyama. Nyama izo zikasangika ni nga nkhalamu kweniso nyama zinyake izo zikurya nyama zinyake, ndipo nyama izi zikajambulika vithuzi panyengo iyo ntchito iyi ikachitikanga. Chiberengero cha nyama nga zovu na vigwere chikaoneskaso kuti nacho chikaba chakukwera kusazgapo nyama zakupambanapambana, kung`anamula kuti chilengiwa chichali makola. Kafukufuku wakwambirila uyo wakaoneskazaso uwemi wamadambo ghakulughakulu pakupwelerera vinthu vyamoyo vyakupambanapambana mchigaba chakumpoto kwa chalo chino. Ndipo kulutiligza kafukufuku uyu kuwovwilenge kusanga uthenga wakukhumbikira chomene pakupwerelera vwachilengiwa kweniso unandi wake m`thengere lakuvikililika la VMWR. Kafukufuku uyu awabowvirengeso kupulikiska uwemi wakukhala na malo ghawemi ghakusingirako vinthu vyamoyo vwakupambanapambana na umo ivyo vikukalira lumoza.
... Insect populations are declining worldwide (Potts et al. 2010, Hallmann et al. 2017, Sánchez-Bayo and Wyckhuys 2019. Two key drivers of this decline are increased temperature extremes as a result of climate change and use of agricultural insecticides (Tilman et al. 2001, Benton et al. 2002, Beketov et al. 2013, Ollerton et al. 2014, Van Lexmond et al. 2015, Sánchez-Bayo and Wyckhuys 2019. ...
Article
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Anyone clicking on this link before October 31, 2020 will be taken directly to the final version of this article on ScienceDirect, which they are welcome to read or download: https://authors.elsevier.com/c/1bjol_17GgHrME . The global intensification of agriculture has resulted in pesticides playing an increasingly important role as anthropogenic stressors and drivers of environmental change. There is also a growing need to determine if other environmental stressors, especially those predicted to worsen with climate change, interact with pesticides to alter their effects on non-target biota. Two such stressors are increased extreme temperature events and periods of food limitation. This study is the first to investigate the combined effects of the world's most widely used insecticide, imidacloprid, with heatwaves and food limitation on a freshwater animal. A 6-week, full-factorial laboratory experiment with Deleatidium spp. mayfly nymphs was performed to investigate the potential for direct and delayed interactive effects of simulated heatwaves and starvation with chronic exposure to a field-realistic concentration of imidacloprid (0.4 μg/L). The experiment included two 6-day simulated heatwaves, one during a starvation period prior to imidacloprid addition, and one during the first 6 days of imidacloprid exposure. The simulated heatwaves alone caused such drastic negative effects on Deleatidium survival and mobility that mainly antagonistic interactions were observed with the other stressors, though delayed synergisms between imidacloprid and the second heatwave also affected mayfly mobility. Time-cumulative toxicity of imidacloprid was evident, with imidacloprid first affecting mayfly mobility after 12 days but eventually causing the strongest effects of all manipulated stressors. However, lethal effects of imidacloprid could only be detected in the absence of heatwaves and starvation, possibly as a result of selection for stronger individuals due to prior exposure to these stressors. Our findings demonstrate that heatwaves of increasing severity will critically affect sensitive freshwater organisms such as mayflies, and that the impacts of widespread pesticide use on freshwater ecosystems under global climate change cannot be ignored.
... While the pan traps in the treatment study had higher counts in NB plots, all Apidae recorded during observational surveys were in FB and HB plots. The majority of these specimens were native bees, which are globally in decline (Potts et al., 2010), therefore the potential of T. vulgaris to also support native pollinators and pollination services would increase its importance as a floral resource. ...
Article
Current agroecosystem management practices have a negative effect on natural enemies and their ability to control insect pests. Conservation biological control through the addition of flowering resources can manage food resources for natural enemies. These floral resources can also provide multiple ecosystem services. Study goals were to determine if perennial Thymus vulgaris L. was attractive to natural enemies and if so, could it be a dual use resource encouraging pest management and providing harvestable product. In 2018 plots in three locations were used to examine the effect of habitat throughout the growing season on the attractiveness of T. vulgaris. Large numbers of Thysanoptera and Hemiptera were collected in all locations, represented by phytophagous Aphididae and Thripidae, and predatory Anthocoridae. Location influenced other families to varying degrees. Seasonal specimen counts were influenced by vegetation density, floral phenology, and predator/prey relationships. In 2019 replicated plots of three treatments were used to examine if harvesting plant material affected the attractiveness of T. vulgaris to natural enemies. Total specimens in 2019 were not significantly different among treatments, indicating removal of blooms did not significantly affect the attractiveness of T. vulgaris. Significant numbers of Thysanoptera and Hemiptera were again collected in all treatments, represented by phytophagous Aphididae and Thripidae. Greater numbers of Diptera and Hymenoptera were also collected. Significant numbers of Thripidae, Aphididae, Mymaridae, and Platygastridae were found in the Family level analyses. Results from both years indicate T. vulgaris was attractive to natural enemy and phytophagous Families. Data from 2018 suggest natural enemy families were attracted to alternative prey and hosts utilizing the foliage rather than flowers but the use of nectar and pollen cannot be ruled out. Data from 2019 suggest the presence of flowers played an important role in the attractiveness of T. vulgaris to micro-hymenopteran parasitoids, Syrphidae, and native Apidae. In conclusion, Thymus vulgaris has the potential to be a dual use floral resource that benefits growers through supporting native enemy populations and pollination services, as well as provide income from the harvest of foliage. It could also be used as a beneficial, harvestable floral resource in urban gardens to encourage pollinator conservation and natural pest control.
... Insect pollinators are estimated to support 9.5% of world food production (Gallai et al., 2009) and wild bees have an important role in the delivery of this ecosystem service (Garibaldi, 2013). However, wild bees have undergone global declines (Woodcock et al., 2016) that have been linked to habitat loss and fragmentation, pathogens (Camerona et al., 2016), climate change and insecticides (Biesmeijer, 2006;Ollerton et al., 2014;Potts, 2010;Winfree et al., 2009). Habitat degradations lead to severe decrease of bee abundance and richness in isolated semi-natural habitats (Krewenka et al., 2011). ...
Article
Full-text available
The investigations on value of various landscapes categories as a foraging habitat for wild bees were carried out in mosaics of small scale agriculture and natural vegetation areas of Kashmir valley during the spring seasons of year 2013 and 2014. In present study we tested the importance of habitat area, landscape composition and configuration on wild bees in valley. The habitats selected were hedgerows, agricultural fields, grasslands, and native woodland. We observed that bee differ in their response to many factors of landscapes. The hedgerows were attractive foraging habitat for native bees. The total species richness was highest in hedgerows. The overall bee faunas overlapped among habitats, bee assemblages in hedgerows were more similar to those in fields than to those woodlands. The flowering shrubs were important in attracting bees. Species richness and abundance of wild bees were surveyed on with independent gradients in local and landscape factors. Total wild bee richness was positively affected by complex landscape configuration, large habitat area and high habitat quality which provide them with assured nesting sites.
Article
Botanists have long identified bilaterally symmetrical (zygomorphic) flowers with more specialized pollination interactions than radially symmetrical (actinomorphic) flowers. Zygomorphic flowers facilitate more precise contact with pollinators, guide pollinator behaviour and exclude less effective pollinators. However, whether zygomorphic flowers are actually visited by a smaller subset of available pollinator species has not been broadly evaluated. We compiled 53 609 floral visitation records in 159 communities and classified the plants' floral symmetry. Globally and within individual communities, plants with zygomorphic flowers are indeed visited by fewer species. At the same time, zygomorphic flowers share a somewhat larger proportion of their visitor species with other co-occurring plants and have particularly high sharing with co-occurring plants that also have zygomorphic flowers. Visitation sub-networks for zygomorphic species also show differences that may arise from reduced visitor diversity, including greater connectance, greater web asymmetry and lower coextinction robustness of both plants and visitor species—but these changes do not necessarily translate to whole plant-visitor communities. These results provide context for widely documented associations between zygomorphy and diversification and imply that species with zygomorphic flowers may face a greater risk of extinction due to pollinator loss.
Article
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The long-term decline of monarch butterflies has been attributed to loss of their milkweed (Asclepias sp.) host-plants after the introduction of herbicide-tolerant crops. However, recent studies report pesticide residues on milkweed leaves that could act as a contributing factor when ingested as part of their larval diet. In this study, we exposed monarch larvae to six pesticides (insecticide: clothianidin; herbicides: atrazine, S-metolachlor; fungicides: azoxystrobin, pyraclostrobin, trifloxystrobin) on their primary host-plant, A. syriaca. Each was tested at mean and maximum levels reported from published analyses of milkweeds bordering cropland and thus represent field-relevant concentrations. Monarch lethal and sub-lethal responses were tracked over their complete development, from early instar larvae to adult death. Overall, we found no impact of any pesticide on immature development time and relatively weak effects on larval herbivory or survival to adulthood. Comparatively stronger effects were detected for adult performance; namely, a 12.5% reduction in wing length in response to the fungicides azoxystrobin and trifloxystrobin. These data collectively suggest that monarch responses to host-plant pesticides are largely sublethal and more pronounced in the adult stage, despite exposure only as larvae. This outcome has important implications for risk assessment and the migratory success of monarchs in North America.
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Insect pollination is essential to many unmanaged and agricultural systems and as such is a key element in food production. However, floral scents that pollinating insects rely on to locate host plants may be altered by atmospheric oxidants, such as ozone, potentially making these cues less attractive or unrecognizable to foraging insects and decreasing pollinator efficacy. We demonstrate that levels of tropospheric ozone commonly found in many rural areas are sufficient to disrupt the innate attraction of the tobacco hawkmoth Manduca sexta to the odor of one of its preferred flowers, Nicotiana alata. However, we further find that visual navigation together with associative learning can offset this disruption. Foraging moths that initially find an ozone-altered floral scent unattractive can target an artificial flower using visual cues and associate the ozone-altered floral blend with a nectar reward. The ability to learn ozone-altered floral odors may enable pollinators to maintain communication with their co-evolutionary partners and reduce the negative impacts that anthropogenically elevated oxidants may have on plant-pollinator systems.
Chapter
Pollination is an essential requirement for fruit and seed set. It is, therefore, crucial for crop productivity and sustenance of flowering plant diversity in their natural habitats. Nearly 90% of flowering plants use a range of animals to achieve pollination. Human-induced environmental changes in recent decades have markedly reduced the diversity, density and distribution of pollinators around the world, resulting in global pollinator crisis. The crisis is also threatening the survival of managed pollinators that are being used routinely for decades for pollination services of a large number of crop species grown in monoculture cropping system. Thus, pollination constraints have raised serious concern on the sustenance of crop productivity and plant diversity in the coming decades. Concerted efforts are being made around the world to study pollinator and pollination both in natural and agricultural habitats to mitigate the crisis. Recent approaches have been to use integrated pollination services using the wild as well as managed pollinators for crop species and to make the agricultural and natural habitats favourable for the sustenance of pollinators. Unfortunately, biologists in the tropics in general and India in particular have remained indifferent about pollinators and pollination services of wild as well as pollinator-dependent crop species. Serious efforts are needed to initiate extensive studies on the pollination ecology of our crops and wild species and make all possible efforts to identify and alleviate the pollinator crisis.
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Insecticides represent an important management tool in agriculture. They provide a low cost and efficacious approach to pest control, where they may be employed both reactively and pre-emptively. It is likely insecticides will continue to play a role in meeting the challenge of feeding a growing global population. The widespread use of insecticides creates potential for negative impacts on non-target invertebrate populations. Many countries have regulatory processes in place to manage these. However, there regulatory processes have potential limitations when it comes to detecting the long-term and large-scale consequences of insecticide use. For example, long-term sub-lethal effects resulting from low dose exposure durations are rarely considered in toxicity tests, while predictable additive effects of mixtures of active ingredient are often ignored. In order to address this data gap, there is substantial scope for using existing spatially and temporally explicit biological records of species occurrence. This could help in monitoring and assessment to support our responsibilities to maintain biodiversity while continuing to grow enough food to feed the human population. How this is achieved poses several problems, both practical and analytical. Here, we describe how national-scale data on the spatial and temporal distribution of native invertebrates can be combined with maps of large-scale insecticide application and exposure risk to explore the actual consequences for non-target native biodiversity. Understanding these impacts on native invertebrates will provide a vital evidence base to inform policy decisions that could complement existing regulatory processes.
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Literature Review
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Compared the composition of Belgian bumblebee faunas before and since 1950. Of 31 species, 14, mostly leguminous and composite foragers from open areas, became very scarce. The relative abundance of 7 species did not change. The relative abundance of 5 forest species has strongly increased. The Belgian potential annual bumblebee population can be estimated at 2.9 × 109 specimens. The decrease of leguminous cultures can explain a reduction of 1.3 × 109 specimens. Modifications of grassland flora due to nitrogenous fertilization and herbicide practices can explain a decrease of 0.15-0.45 × 109 specimens. The strong increase of forest area can explain the increase of forest species. -from English summary
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The Report “A metagenomic survey of microbes in honey bee colony collapse disorder” (D. L. Cox-Foster et al. , 12 October 2007, p. [283][1]) identified Israeli acute paralysis virus (IAPV) as a putative marker for colony collapse disorder (CCD). It also purports to show a relationship between U.
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First estimation of faunistic drift by bumblebees of Belgium (Hymenoptera, Apidae). Summary. The authors compare the composition of belgian bumblebee faunas before and since 1950. Of 31 species, 14 became very scarse, mostly Leguminous and Composites foragers from open areas . The relative abundance of 7 species did not change. The relative abundance of 5 forest species has strongly increased. The belgian potential annual bumblebee population can be estimated at 2.9x10E9 specimens. The decrease of leguminous cultures can explain the disparition of approximately 1.3x10E9 specimens. The modifications of grassland flora due to nitrogenous fertilization and herbicide practices can explain a decrease of 0.15 to 0.45x10E9 specimens. The strong increase of forest area (+26% for the only Wallonie region) can explain the increase of forest species. Other factors (entomological collection, destruction by cars, insecticides, rasing of road sides) seem to be negligeable.
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We review evidence from around the world for bumblebee declines and review management to mitigate threats. We find that there is evidence that some bumblebee species are declining in Europe, North America, and Asia. People believe that land-use changes may be having a negative effect through reductions in food plants in many parts of the world, but that other factors such as pathogens may be having a stronger effect for a few species in some regions (especially for Bombus s. str. in North America). Evidence so far is that greater susceptibility to land-use change is associated world-wide with small climatic ranges, range edges, and late-starting colony-development cycles. More evidence is needed on the roles of pollen specialization, nest sites, hibernation sites, and pesticides. It is still too early to assess the success of schemes aimed at improving forage in agricultural and conservation areas. However, schemes aimed at raising public awareness have been very successful. Until proven safe, we recommend that live bumblebees should not be moved across continents or oceans for commercial pollination.
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Most ecological processes and interactions depend on scales much larger than a single habitat, and therefore it is important to link spatial patterns and ecological processes at a landscape scale. Here, we analyzed the effects of landscape context on the distribution of bees (Hymenoptera: Apoidea) at multiple spatial scales with respect to the following hypotheses: (1) Local abundance and diversity of bees increase with increasing proportion of the surrounding seminatural habitats. (2) Solitary wild bees, bumble bees, and honey bees respond to landscape context at different spatial scales. We selected 15 landscape sectors and determined the percentage of seminatural habitats and the diversity of habitat types at eight spatial scales (radius 250-3000 m) by field inspections and analyses of vegetation maps using two Geographic Information Systems. The percentage of semi- natural habitats varied between 1.4% and 28%. In the center of each landscape sector a patch of potted flowering plants (four perennial and two annual species) was placed in the same habitat type, a grassy field margin adjacent to cereal fields. In all, 865 wild bee individuals and 467 honey bees were observed and an additional 475 individuals were caught for species identification. Species richness and abundance of solitary wild bees showed a close positive correlation with the percentage of seminatural habitats at small scales up to 750 m, whereas bumble bees and honey bees did not respond to landscape context at these scales. In contrast, honey bees were correlated with landscape context at large scales. The densities of flower-visiting honey bees even increased with decreasing proportion of seminatural habitats at a radius of 3000 m. We are not aware of any empirical studies showing contrasting foraging patterns related to landscape context at different spatial scales. We conclude (1) that local landscape destruction affects solitary wild bees more than social bees, possibly changing mutualistic plant-pollinator and competitive wild bees- honey bees interactions and (2) that only analyses of multiple spatial scales may detect the importance of the landscape context for local pollinator communities.
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We review direct and indirect impacts of invasive alien species (focussing on plants and insects) on native bees worldwide. Although there is a rapidly growing body of research into the effects of invasive alien plants on native plant pollination via disruption of native mutualisms, there has been little research on the impacts of invasive alien plants directly on bees. Such impacts are likely to vary according to the taxon of plant, the functional specificity of the native bees, and ecosystem context. Conversely, there have been more attempts to document impacts of invasive alien social bees on native bees. Most of these studies only indirectly evaluate competition for resources, have focused on a few native species and findings are sometimes contradictory. However, some studies showed strong negative impacts, suggesting that effects might be species-specific. Additionally, pathogen spillover and reproductive disruption due to interspecific mating has been demonstrated among some closely related taxa. Where we lack unequivocal evidence for impacts however, this should not be interpreted as lack of effect. We recommend that future studies are robustly designed and consider impacts on genetic, species (particularly solitary bees) and ecosystem biodiversity.
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Summary 1. We assess the importance of body mass and the minimum ambient temperature at which foraging occurs in determining the warm-up rates and thoracic temperatures in flight at an air temperature of 22 °C of 55 species of bee (Hymenoptera: Apoidea) from six families adapted to a variety of thermal environments. 2. To control for the effects of taxonomic differences in the relationships between these variables, we use multiple regression incorporated in the phylogen- etic regression method developed by Grafen (1989). 3. The prediction made by May (1976) that for very small heterotherms warm- up rate will correlate positively with body mass is confirmed when the effects of phylogeny and the thermal environment to which the bee is adapted have been controlled for. The relationship between warm-up rate and body mass within the Apoidea is thus not an extension to lower body masses of the relationship found for heterothermic vertebrates. 4. Having controlled for the effects of body mass in our analyses, we demonstrate that bees able to fly at lower ambient temperatures have higher thoracic temperatures and warm-up rates than bees adapted to wanner environ- ments. 5. There is some suggestion that kleptoparasitic bees, being freed from the need to forage in order to provision cells, have lower warm-up rates than provisioning species. 6. The significance of these relationships in the ecology of bees is discussed in relation to studies of body temperatures and warm-up rates in bees and other insects.
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There is a voluminous literature on pollination and dispersal, very little of which deals with the consequences of reproductive failure and its most extreme consequence: extinction. The risk of plant extinctions can be assessed by considering the probability of dispersal or pollinator failure, reproductive dependence on the mutualism and demographic dependence on seeds. Traits for ranking species rapidly according to these three criteria are indicated. Analysis of case studies suggests that plants often compensate for high risk in one of the three categories by low risk in another. For example, self-incompatible plants with rare specialist pollinators often propagate vegetatively. Some systems, including elements of the Cape flora and lowland tropical rain forest, lack compensatory traits and the risk of plant extinction from failed mutualism is high. 'What escapes the eye, however, is a much more insidious kind of extincnction: the extinction of ecological interactions' Janzen (1974).
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Growing evidence indicates that European managed honey bees are in decline, but information for Europe remains patchy and localized. Here we compile data from 18 European countries to assess trends in the number of honey bee colonies and beekeepers between 1965 and 2005. We found consistent declines in colony numbers in central European countries and some increases in Mediterranean countries. Beekeeper numbers have declined in all of the European countries examined. Our data support the view that honey bees are in decline at least in some regions, which is probably closely linked to the decreasing number of beekeepers. Our data on colony numbers and beekeepers must, however, be interpreted with caution due to different approaches and socioeconomic factors in the various countries, thereby limiting their comparability. We therefore make specific recommendations for standardized methodologies to be adopted at the national and global level to assist in the future monitoring of honey bees.
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Plant-animal mutualistic networks can be described as bipartite graphs depicting the interactions between two distinct sets: plants and animals. These mutualistic networks have been found to be highly structured. Specifically, they show a nested pattern in which specialists interact with proper subsets of the species generalists interact with. This pattern is important for understanding coevolution in species-rich communities which can be reduced neither to pairs of coevolving species nor to diffuse, randomly-interacting assemblages. We discuss the dynamic implications of network structure from the points of view of coevolution, community ecology, and conservation biology.
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Mean global temperatures have risen this century, and further warming is predicted to continue for the next 50-100 years. Some migratory species can respond rapidly to yearly climate variation by altering the timing or destination of migration, but most wildlife is sedentary and so is incapable of such a rapid response. For these species, responses to the warming trend should be slower, reflected in poleward shifts of the range. Such changes in distribution would occur at the level of the population, stemming not from changes in the pattern of indivduals' movements, but from changes in the ratios of extinctions to colonizations at the northern and southern boundaries of the range. A northward range shift therefore occurs when there is net extinction at teh southern boundary or net colonization at the northern boundary. However, previous evidence has been limited to a single species or to only a portion of the species' range. Here we provide the first large-scale evidence of poleward shifts in entire species' ranges. In a sample of 35 non-migratory European butterflies, 63% have ranges that have shifted to the north by 35-240 km during this century, and only 3% have shifted to the south.
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Agricultural intensification poses a serious threat to biodiversity as a consequence of increased land-use intensity, decreased landscape heterogeneity and reduced habitat diversity. Although there is interest in the preservation of total species richness of an agricultural landscape (gamma diversity), the effects of intensification have been assessed primarily by species richness at a local scale (alpha diversity). This ignores species richness between local communities (beta diversity), which is an important component of total species richness. In this study, measures of land-use intensity, landscape structure and habitat diversity were related to gamma, alpha and beta diversity of wild bees (Apoidea), carabid beetles (Carabidae), hoverflies (Syrphidae), true bugs (Heteroptera) and spiders (Araneae) within 16 local communities in 24 temperate European agricultural landscapes. The total landscape species richness of all groups was most strongly affected by increased proximity of semi-natural habitat patches. Bees also decreased in landscapes with a high intensity of farmland management, demonstrating additive effects of both factors. Separating total species diversity into components, the decrease in total species richness could be attributed primarily to a decrease in species diversity between local communities. Species richness of the local communities of all investigated groups decreased with increasing land-use intensity and, in the case of spiders, decreasing proximity of the semi-natural habitat patches. The effect of increased habitat diversity appeared to be of secondary importance to total species richness but caused a shift in the relative contribution of alpha and beta diversity towards the latter. Synthesis and applications. This study demonstrates that the effects of agricultural change operate at a landscape level and that examining species diversity at a local level fails to explain the total species richness of an agricultural landscape. The coincidence of patterns of beta diversity with those of gamma diversity emphasizes that such information is of crucial importance for the implementation and evaluation of restoration programmes aiming to restore sustainable countryside diversity. As local extinction processes in highly fragmented landscapes shape biodiversity, priority should be given to the conservation of diverse agricultural landscape remnants in Europe.
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In 1996, a naturally occurring nest of an introduced bumblebee, Bombus terrestris L., was found in Monbetsu in the Hidaka region of southern Hokkaido, indicating that it had become naturalized in Japan. In this region, monitoring of B. terrestris has been continued at two sites. The numbers of B. terrestris captured or observed have increased rapidly during the eight years since the evidence of its naturalization was found. Seasonally, the queens of naturalized B. terrestris have appeared as early as mid-April each spring. Queens were observed continuously during the period from April to October, workers from May to October, and males from July to October. B. terrestris was shown to forage among various flowering plants, 40% −70% of the species of flowering plants upon which native bumblebees fed. Nine of ten natural nests of B. terrestris discovered during the study were found in abandoned underground rodent nests. The nest sites of this species were similar to those of B. hypocrita sapporoensis Cockerell, and B. diversus tersatus Smith. B. terrestris clearly has the potential to compete with native bumblebees for floral resources and nest sites. The mean number of new queens born in the colonies of B. terrestris was 4.4 times larger than that of the native bumblebees. This strongly suggested superior reproductive ability of B. terrestris compared with native bumblebees in the region.
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Apiculture has been in decline in both Europe and the USA over recent decades, as is shown by the decreasing numbers of managed honey bee (Apis mellifera L.) colonies (Ellis et al., 2010; Potts et al., 2010). It therefore is crucial to make beekeeping a more attractive hobby and a less laborious profession, in order to encourage local apiculture and pollination. Apart from socio-economic factors, which can only be addressed by politicians, sudden losses of honey bee colonies have occurred, and have received considerable public attention. Indeed, in the last few years, the world's press has been full of eye catching but often uninformative headlines proclaiming the dramatic demise of the honey bee, a world pollinator crisis and the spectre of mass human starvation. "Colony Collapse Disorder" (CCD) in the USA has attracted great attention, and scientists there and in Europe are working hard to provide explanations for these extensive colony losses. Colony losses have also occurred elsewhere (Figs 1 and 2), but examination of the historical record shows that such extensive losses are not unusual (vanEngelsdorp and Meixner, 2009). African honey bees and Africanized ones in the Americas survive without Varroa destructor treatment, whilst the mite has not yet been introduced into Australia. This global picture indicates a central role of this particular ectoparasitic mite for colony losses.
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Abstract 1. The small hive beetle, Aethina tumida, is a parasite of honeybee (Apis mellifera) colonies native to sub-Saharan Africa and has become an invasive species. In North America the beetle is now sympatric with bumblebees, Bombus, not occurring in its native range. Laboratory studies have shown that small hive beetles can reproduce in bumblebee colonies but it was not known whether infestations occur in the field. 2. For the first time, infestation of bumblebee colonies by small hive beetles was investigated in the field. Commercial Bombus impatiens colonies (n= 10) were installed in proximity to infested apiaries. Within 8 weeks, all colonies that were alive in the 5-week observation period (n= 9) became naturally infested with adult small hive beetles and successful small hive beetle reproduction occurred in five colonies. 3. In four-square choice tests, the beetles were attracted to both adult bumblebee workers and pollen from bumblebee nests, suggesting that these odours may serve as cues for host finding. 4. The data indicate that bumblebee colonies may serve as alternative hosts for small hive beetles in the field. To foster the conservation of these essential native pollinators, investigations on the actual impact of small hive beetles on wild bumblebee populations are suggested.
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Pollen limitation on a plant community level has received little attention, although it might show which pollination-related traits may cause pollen limitation to vary among species. To address several central questions in plant reproductive biology, we investigated pollen limitation in 11 plant species, including visitation and specialisation levels of all species. The female reproductive success of most species within the studied plant community was not pollen limited, but a general tradeoff between seed production and seed weight occurred as a response to supplemental pollination. In contrast to general notion, we did not find that less visited species were most pollen limited. Instead, it appears that species with high visitation rates were most pollen limited. Our study provided conflicting evidence to whether specialisation levels may affect the degree of pollen limitation within the study community. We discuss these findings in the context of recent reviews on the occurrence, causes and consequences of pollen limitation in plants. In particular, we propose that, although pollen limitation is an important phenomenon, 1) the majority of species within a plant community may not experience pollen limitation at a given moment, 2) that common notions of which plant species should experience pollen limited reproductive success do not hold true in the studied plant community, and 3) that offspring quality is as likely affected by surplus pollen loads as is the number of offspring.
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To provide replicate samples of local bee populations in a nature preserve, light traps operated continuously on Barro Colorado Island (BCI), Panama, collected bees for 17 years, including 10 years following invasion by African Apis mellifera. Honey bees appeared in light traps as the first swarms colonized the Panama Canal area. Their numbers followed seasonal trends shown in inde-pendent studies, thus indicating bee abundance and activity in a large area. No measurable population-level impact of competition between this invading honey bee and native bees, despite many demonstrations of resource competition at flower patch and colony levels, changed annual abundances of all 15 native bee species. Native bee abundance did not decrease, nor did native bees show substantial reciprocal yearly change with honey bee abundance. One strong negative correlation of bee catches with an extremely rainy year was found. However, multiple regression using rainfall and honey bee abundance as the independent variables showed that neither was responsible for bee population change over 17 years. Nearly half the native species declined during a year that displayed peak honey bee number. That competition from honey bees on an island the size of BCI was necessarily reduced below impact levels expected on the mainland is discussed using a model of resource and consumer density, foraging range, and island size.
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Bateman’s principle states that male fitness is usually limited by the number of matings achieved, while female fitness is usually limited by the resources available for reproduction. When applied to flowering plants this principle leads to the expectation that pollen limitation of fruit and seed set will be uncommon. However, if male searching for mates (including pollen dissemination via external agents) is not sufficiently successful, then the reproductive success of both sexes (or both sex functions in hermaphroditic plants) will be limited by number of matings rather than by resources, and Bateman’s principle cannot be expected to apply. Limitation of female success due to inadequate pollen receipt appears to be a common phenomenon in plants. Using published data on 258 species in which fecundity was reported for natural pollination and hand pollination with outcross pollen, I found significant pollen limitation at some times or in some sites in 159 of the 258 species (62%). When experiments were performed multiple times within a growing season, or in multiple sites or years, the statistical significance of pollen limitation commonly varied among times, sites or years, indicating that the pollination environment is not constant. There is some indication that, across species, supplemental pollen leads to increased fruit set more often than increased seed set within fruits, pointing to the importance of gamete packaging strategies in plant reproduction. Species that are highly self-incompatible obtain a greater benefit relative to natural pollination from artificial application of excess outcross pollen than do self-compatible species. This suggests that inadequate pollen receipt is a primary cause of low fecundity rates in perennial plants, which are often self-incompatible. Because flowering plants often allocate considerable resources to pollinator attraction, both export and receipt of pollen could be limited primarily by resource investment in floral advertisement and rewards. But whatever investment is made is attraction, pollinator behavioral stochasticity usually produces wide variation among flowers in reproductive success through both male and female functions. In such circumstances the optimal deployment of resources among megaspores, microspores, and pollinator attraction may often require more flowers or more ovules per flower than will usually be fertilized, in order to benefit from chance fluctuations that bring in large number of pollen grains. Maximizing seed set for the entire plant in a stochastic pollination environment might thus entail a packaging strategy for flower number or ovule number per flower that makes pollen limitation of fruit or seed set likely. Pollen availability may limit female success in individual flowers, entire plants (in a season or over a lifetime), or populations. The appropriate level must be distinguished depending on the nature of the question being addressed.
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The small hive beetle (SHB, Aethina tumida) is a parasite and scavenger of honeybee colonies. Here, we conducted laboratory experiments to investigate the potential of SHB as a vector of honeybee viruses. Using RT-PCR methods, Deformed Wing Virus (DWV) was detected in adult SHBs that: (1) were fed with dead workers with deformed wings, (2) were fed with DWV-positive brood, and (3) were associated with DWV-contaminated wax. SHB became significantly more often infected through feeding on virus infected workers, brood and the virus contaminated wax compared to pollen and the controls, where no infections were found. DWV was also detected in adult SHB after trophallaxis with infected workers. Further, among SHBs identified as DWV-positive, 40% of beetles carried negative stranded RNA of DWV, indicating virus replication. Our results suggest that SHB can be infected with honeybee viruses via food-borne transmission and have the potential of being a biological vector of honeybee viruses.
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The density of wild honeybee colonies (Apis mellifera) in the African dry highland savannahs was estimated in three Nature Reserves in Gauteng, South Africa (Ezemvelo, Leeuwfontein, Suikerbosrand) based on the genotypes of drones which were caught at drone congregation areas. Densities were estimated to range between 12.4 and 17.6 colonies per square kilometer. In addition colony densities were estimated in two German National parks (Müritz and Hochharz) and a commercial mating apiary. The density of colonies was significantly lower at the German sampling sites with estimates of 2.4–3.2 colonies per square kilometer, which closely matches the nation-wide density of colonies kept by beekeepers. This shows that the densities of colonies observed in wild populations under the harsh conditions of the African dry savannahs exceeds that of Germany by far, in spite of intensive beekeeping. The intensity of apiculture in Europe is therefore unlikely to compensate for the loss of habitats suitable for wild honeybees due to agriculture, forestry and other cultivation of land.
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Evidence for interspecific competition between honey bees and wild bees was studied on 15 calcareous grasslands with respect to: (1) foraging radius of honey bees, (2) overlap in resource use, and (3) possible honey bee effects on species richness and abundance of flower-visiting, ground-nesting and trap-nesting wild bees. The grasslands greatly differed in the number of honey bee colonies within a radius of 2 km and were surrounded by agricultural habitats. The number of flower-visiting honey bees on both potted mustard plants and small grassland patches declined with increasing distance from the nearest apiary and was almost zero at a distance of 1.5–2.0 km. Wild bees were observed visiting 57 plant species, whereas honey bees visited only 24 plant species. Percentage resource overlap between honey bees and wild bees was 45.5%, and Hurlbert’s index of niche overlap was 3.1. In total, 1849 wild bees from 98 species were recorded on the calcareous grasslands. Neither species richness nor abundance of wild bees were negatively correlated with the density of honey bee colonies (within a radius of 2 km) or the density of flower-visiting honey bees per site. Abundance of flower- visiting wild bees was correlated only with the percentage cover of flowering plants. In 240 trap nests, 1292 bee nests with 6066 brood cells were found. Neither the number of bee species nor the number of brood cells per grassland was significantly correlated with the density of honey bees. Significant correlations were found only between the number of brood cells and the percentage cover of shrubs. The number of nest entrances of ground-nesting bees per square metre was not correlated with the density of honey bees but was negatively correlated with the cover of vegetation. Interspecific competition by honey bees for food resources was not shown to be a significant factor determining abundance and species richness of wild bees.
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To better understand the dynamics of bee populations in crops, we assessed the effect of landscape context and habitat type on bee communities in annual entomophilous crops in Europe. We quantified bee communities in five pairs of crop-country: buckwheat in Poland, cantaloupe in France, field beans in the UK, spring oilseed rape in Sweden, and strawberries in Germany. For each country, 7–10 study fields were sampled over a gradient of increasing proportion of semi-natural habitats in the surrounding landscape. The CORINE land cover classification was used to characterize the landscape over a 3 km radius around each study field and we used multivariate and regression analyses to quantify the impact of landscape features on bee abundance and diversity at the sub-generic taxonomic level. Neither overall wild bee abundance nor diversity, taken as the number of sub-genera, was significantly affected by the proportion of semi-natural habitat. Therefore, we used the most precise level of the CORINE classification to examine the possible links between specific landscape features and wild bee communities. Bee community composition fell into three distinct groups across Europe: group 1 included Poland, Germany, and Sweden, group 2 the UK, and group 3 France. Among all three groups, wild bee abundance and sub-generic diversity were affected by 17 landscape elements including some semi-natural habitats (e.g., transitional woodland-shrub), some urban habitats (e.g., sport and leisure facilities) and some crop habitats (e.g., non-irrigated arable land). Some bee taxa were positively affected by urban habitats only, others by semi-natural habitats only, and others by a combination of semi-natural, urban and crop habitats. Bee sub-genera favoured by urban and crop habitats were more resistant to landscape change than those favoured only by semi-natural habitats. In agroecosystems, the agricultural intensification defined as the loss of semi-natural habitats does not necessarily cause a decline in evenness at the local level, but can change community composition towards a bee fauna dominated by common taxa.
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The paper provides the first estimate of the composition and structure of alien plants occurring in the wild in the European continent, based on the results of the DAISIE project (2004-2008), funded by the 6th Framework Programme of the European Union and aimed at "creating an inventory of invasive species that threaten European terrestrial, freshwater and marine environments". The plant section of the DAISIE database is based on national checklists from 48 European countries/regions and Israel; for many of them the data were compiled during the project and for some countries DAISIE collected the first comprehensive checklists of alien species, based on primary data (e.g., Cyprus, Greece, R Y. R. O. Macedonia, Slovenia, Ukraine). In total, the database contains records of 5789 alien plant species in Europe (including those native to a part of Europe but alien to another part), of which 2843 are alien to Europe (of extra-European origin). The research focus was on naturalized species; there are in total 3749 naturalized aliens in Europe, of which 1780 are alien to Europe. This represents a marked increase compared to 1568 alien species reported by a previous analysis of data in Flora Europaea (1964-1980). Casual aliens were marginally considered and are represented by 1507 species with European origins and 872 species whose native range falls outside Europe. The highest diversity of alien species is concentrated in industrialized countries with a tradition of good botanical recording or intensive recent research. The highest number of all alien species, regardless of status, is reported from Belgium (1969), the United Kingdom (1779) and Czech Republic (1378). The United Kingdom (857), Germany (450), Belgium (447) and Italy (440) are countries with the most naturalized neophytes. The number of naturalized neophytes in European countries is determined mainly by the interaction of temperature and precipitation; it increases with increasing precipitation but only in climatically warm and moderately warm regions. Of the nowadays naturalized neophytes alien to Europe, 50% arrived after 1899, 25% after 1962 and 10% after 1989. At present, approximately 6.2 new species, that are capable of naturalization, are arriving each year. Most alien species have relatively restricted European distributions; half of all naturalized species occur in four or fewer countries/regions, whereas 70% of non-naturalized species occur in only one region. Alien species are drawn from 213 families, dominated by large global plant families which have a weedy tendency and have undergone major radiations in temperate regions (Asteraceae, Poaceae, Rosaceae, Fabaceae, Brassicaceae). There are 1567 genera, which have alien members in European countries, the commonest being globally-diverse genera comprising mainly urban and agricultural weeds (e.g., Amaranthus, Chenopodium and Solanum) or cultivated for ornamental purposes (Cotoneaster, the genus richest in alien species). Only a few large genera which have successfully invaded (e.g., Oenothera, Oxalis, Panicum, Helianthus) are predominantly of non-European origin. Conyza canadensis, Helianthus tuberosus and Robinia pseudoacacia are most widely distributed alien species. Of all naturalized aliens present in Europe, 64.1% occur in industrial habitats and 58.5% on arable land and in parks and gardens. Grasslands and woodlands are also highly invaded, with 37.4 and 31.5%, respectively, of all naturalized aliens in Europe present in these habitats. Mires, bogs and fens are least invaded; only approximately 10% of aliens in Euope occur there. Intentional introductions to Europe (62.8% of the total number of naturalized aliens) prevail over unintentional (37.2%). Ornamental and horticultural introductions escaped from cultivation account for the highest number of species, 52.2% of the total. Among unintentional introductions, contaminants of seed, mineral materials and other commodities are responsible for 1091 alien species introductions to Europe (76.6% of all species introduced unintentionally) and 363 species are assumed to have arrived as stowaways (directly associated with human transport but arriving independently of commodity). Most aliens in Europe have a native range in the same continent (28.6% of all donor region records are from another part of Europe where the plant is native); in terms of species numbers the contribution of Europe as a region of origin is 53.2%. Considering aliens to Europe separately, 45.8% of species have their native distribution in North and South America, 45.9% in Asia, 20.7% in Africa and 5.3% in Australasia. Based on species composition, European alien flora can be classified into five major groups: (1) north-western, comprising Scandinavia and the UK; (2) west-central, extending from Belgium and the Netherlands to Germany and Switzerland; (3) Baltic, including only the former Soviet Baltic states; (4) east-central, comprizing the remainder of central and eastern Europe; (5) southern, covering the entire Mediterranean region. The clustering patterns cut across some European bioclimatic zones; cultural factors such as regional trade links and traditional local preferences for crop, forestry and ornamental species are also important by influencing the introduced species pool. Finally, the paper evaluates a state of the art in the field of plant invasions in Europe, points to research gaps and outlines avenues of further research towards documenting alien plant invasions in Europe. The data are of varying quality and need to be further assessed with respect to the invasion status and residence time of the species included. This concerns especially the naturalized/casual status; so far, this information is available comprehensively for only 19 countries/regions of the 49 considered. Collating an integrated database on the alien flora of Europe can form a principal contribution to developing a European-wide management strategy of alien species.
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Abstract Bees are generally regarded as beneficial insects for their role in pollination, and in the case of the honeybee Apis mellifera, for production of honey. As a result several bee species have been introduced to countries far beyond their home range, including A. mellifera, bumblebees (Bombus sp.), the alfalfa leafcutter bee Megachile rotundata, and various other solitary species. Possible negative consequences of these introductions include: competition with native pollinators for floral resources; competition for nest sites; co-introduction of natural enemies, particularly pathogens that may infect native organisms; pollination of exotic weeds; and disruption of pollination of native plants. For most exotic bee species little or nothing is known of these possible effects. Research to date has focused mainly on A. mellifera, and has largely been concerned with detecting competition with native flower visitors. Considerable circumstantial evidence has accrued that competition does occur, but no experiment has clearly demonstrated long-term reductions in populations of native organisms. Most researchers agree that this probably reflects the difficulty of carrying out convincing studies of competition between such mobile organisms, rather than a genuine absence of competitive effects. Effects on seed set of exotic weeds are easier to demonstrate. Exotic bees often exhibit marked preferences for visiting flowers of exotic plants. For example, in Australia and New Zealand many weeds from Europe are now visited by European honeybees and bumblebees. Introduced bees are primary pollinators of a number of serious weeds. Negative impacts of exotic bees need to be carefully assessed before further introductions are carried out.
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1. When considered together, the diversity and abundance of biologically similar organisms (e.g. pollinators) within a community, are more powerful in assessing the effects of disruption than when taken separately. The log-normal model of abundance and diversity is illustrated as a tool in applied ecology. 2. Data were collected from sampling pollinating bees over 8 years in 13 blueberry fields in New Brunswick, Canada. These data were used to test the log-normality of the species diversity and abundance relationships with respect to the disruption of communities by applications of the insecticide fenitrothion to nearby forests. 3. Ecosystemic integrity (health) of the lowbush blueberry fields was assessed by using species diversity and abundance in Sugihara's (1980) sequential breakage model. This model was used to test the log-normality of data sets from fields which were affected and unaffected by fenitrothion. 4. On both spatial and temporal bases, fields unaffected by the pesticide fitted well to the log-normal model of species diversity and abundance, whereas affected fields departed from that pattern. Thus, the relationship is useful because the samples from fields affected by fenitrothion presumably represent compromised integrity and decline in ecosystemic health. 5. Shannon-Wiener's hierarchical diversity indices and Jaccard's indices of similarity were found to have little value in measuring ecosystemic health. For the former, none of the indices calculated showed any difference between communities with a log-normal pattern of species diversity and abundance, and those without it. Jaccard's index of similarity was low and similar in all the cases. 6. In general, ecosystemic health should not be narrowly assessed through biodiversity but must include taxonomic and population changes together. The log-normal relationship linking species diversity and abundance is an objective standard against which applied ecologists can test ecosystemic integrity, disruption, health, ill-health, and reconstitution.
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Apis mellifera is composed of three evolutionary branches including mainly African (branch A), western and northern European (branch M), and southeastern European (branch C) populations. The existence of morphological clines extending from the equator to the Polar Circle through Morocco and Spain raised the hypothesis that the branch M originated in Africa. Mitochondrial DNA analysis revealed that branches A and M were characterized by highly diverged lineages implying very remote links between both branches. It also revealed that mtDNA haplotypes from lineages A coexisted with haplotypes M in the Iberian Peninsula and formed a south-north frequency cline, suggesting that this area could be a secondary contact zone between the two branches. By analyzing 11 populations sampled along a France-Spain/Portugal-Morocco-Guinea transect at 8 microsatellite loci and the DraI RFLP of the COI-COII mtDNA marker, we show that Iberian populations do not present any trace of 'africanization' and are very similar to French populations when considering microsatellite markers. Therefore, the Iberian Peninsula is not a transition area. The higher haplotype A variability observed in Spanish and Portuguese samples compared to that found in Africa is explained by a higher mutation rate and multiple and recent introductions. Selection appears to be the best explanation to the morphological and allozymic clines and to the diffusion and maintenance of African haplotypes in Spain and Portugal.
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Abstract We empirically assessed the long-term changes in the rare species assemblage of a Mediterranean flora, in terms of species life history traits, niche and biogeographic features, and taxonomic groups. We used a 115-year historical record of ca. 2100 plant species occurrences in a 6250 km2 region in Mediterranean France. Species were assigned to two classes of regional abundance for the years 1886 and 2001 (rare species, i.e. exhibiting one or two occurrences vs. nonrare species), and to three classes of abundance changes during 1886–2001 (decreasing/extinct, stable, increasing/immigrant). Then, we tested whether species regional abundance and species abundance change were related to their morphological and life-history traits (life form, perenniality, height, dispersal agent, pollination mode), niche and biogeographic features (habitat specialization, level of endemism, biogeographic origin) and taxonomic group. The regional assemblage of rare species was not biologically random and significantly changed between 1886 and 2001. Species classified as rare in 1886 had a significantly higher rate of extinction in the study region during 1886–2001. The highest rate of regression/extinction was found among hydrophyte and/or water-dispersed rare species, and among annual rare species. However, herbaceous perennial, tree and wind-dispersed rare species significantly increased in abundance during 1886–2001. Rare species with Eurosiberian distributions, occurring at the southern margin of their range in the study region, dramatically declined or went extinct in the region during 1886–2001; whereas rare species with Mediterranean affinities remained significantly stable. We also found strong evidence for taxonomic patterns in species abundance and abundance changes from 1886 to 2001. The long-term biological changes documented here in the rare species assemblage of a Mediterranean flora are consistent with the predicted consequences of climate and land use changes currently occurring in the Mediterranean Basin. With the potential decline or even extinction of entire taxa and the loss of southern ecotypes of widespread Eurosiberian species, both evolutionary history and speciation potential of the Mediterranean Region could be strongly altered in future decades.
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The synergistic effect of a range of ergosterol-biosynthesis-inhibiting (EBI) fungicides and a pyrethroid insecticide was studied in the honeybee (Apis mellifera L.). Various EBI fungicides were combined separately with the pyrethroid lambda-cyhalothrin at ratios derived from their recommended application rates to represent tank-mixing in the field. The mixture was then applied topically to the thorax of honeybees, and mortality assessed 24 h post-treatment. All the fungicides tested increased the toxicity of lambda-cyhalothrin to honeybees. The fungicide propiconazole was found to have the strongest synergistic effect, decreasing the LD50 of lambda-cyalothrin from 68.0 ng bee−1 to 4.2 ng, thus having a synergistic ratio of 16.2. Hazard ratios were calculated for lambda-cyhalothrin and fungicide mixtures using a recommended application rate of 7.5 g a.i. ha−1. The hazard ratio for lambda-cyhalothrin alone was 110, but when mixed with fungicide synergists, the hazard ratio ranged from 366 with flutriafol to 1786 with propiconazole. A blank formulation of a fungicide (without the active ingredient prochloraz) had little effect on the toxicity of lambda-cyhalothrin, indicating that it is primarily the fungicide active ingredient that is responsible for the synergistic effect. The results are discussed in terms of the potential hazard posed by pesticide synergism to honeybees in the field.
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We studied the spread of the newly introduced parasitic mite, Varma jacobsoni Oudemans, within California's population of the feral honey bee, Apis mellifera L., by examining worker bees taken from 208 colonies in 1990, 124 of which were examined again in 1993. The samples taken in 1990 did not contain V. jacobsoni mites. In 1993, 75% of the colonies examined in an area located near Sacramento, CA, no longer existed, and all surviving colonies were infested with V. jacobsoni. In an area located near the Californian central coast, 84% of the nest sites examined were occupied and few colonies contained detectable levels of V. jacobsoni. The probability of survival for colonies that have not survived a winter yet (founder colonies) has been previously reported to be low in areas with a temperate climate. Data collected in an area with a low level of Varroa mite infestation suggest that the probability of founder colony survival is higher in California with a mostly Mediterranean climate. The data collected in areas with a high level of Varroa mite infestation suggest that the parasite reduces the mean life span of feral honey bee colonies in California to go between 6 mo and 1 yr. The parasite was widely spread in areas with a high density of commercial colonies. This suggests that the fast spread of the parasite is caused mostly by migration of commercial colonies. We discuss the consequences of the decline of the feral honey bee population on pollination and on the invasion of California by Africanized bees.
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The cause of colony collapse disorder remains unknown, although some possible explanations for the loss of honey bee colonies can be ruled out.