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The conservation and restoration of wild bees
Annals of the New York Academy of Sciences
Abstract
Bees pollinate most of the world's wild plant species and provide economically valuable pollination services to crops; yet knowledge of bee conservation biology lags far behind other taxa such as vertebrates and plants. There are few long-term data on bee populations, which makes their conservation status difficult to assess. The best-studied groups are the genus Bombus (the bumble bees), and bees in the EU generally; both of these are clearly declining. However, it is not known to what extent these groups represent the approximately 20,000 species of bees globally. As is the case for insects in general, bees are underrepresented in conservation planning and protection efforts. For example, only two bee species are on the global IUCN Red List, and no bee is listed under the U.S. Endangered Species Act, even though many bee species are known to be in steep decline or possibly extinct. At present, bee restoration occurs mainly in agricultural contexts, funded by government programs such as agri-environment schemes (EU) and the Farm Bill (USA). This is a promising approach given that many bee species can use human-disturbed habitats, and bees provide valuable pollination services to crops. However, agricultural restorations only benefit species that persist in agricultural landscapes, and they are more expensive than preserving natural habitat elsewhere. Furthermore, such restorations benefit bees in only about half of studied cases. More research is greatly needed in many areas of bee conservation, including basic population biology, bee restoration in nonagricultural contexts, and the identification of disturbance-sensitive bee species.
... When talking about functional foods, it is important to highlight the role of bees, insects that have existed for over 125 million years, and are able to explore almost all terrestrial biomes (Kanaka-Gantenbein;). In addition, bees are important in environmental preservation since they are the main pollinators (Winfree, 2010;Beche et al., 2022). About 90% of plant species are pollinated by animals, and bees are the main pollinators in most ecosystems (Winfree, 2010). ...
... In addition, bees are important in environmental preservation since they are the main pollinators (Winfree, 2010;Beche et al., 2022). About 90% of plant species are pollinated by animals, and bees are the main pollinators in most ecosystems (Winfree, 2010). Beyond their role in the preservation of wild species, bees play a crucial role in the pollination of agricultural crops (Winfree, 2010;Beche et al., 2022). ...
... About 90% of plant species are pollinated by animals, and bees are the main pollinators in most ecosystems (Winfree, 2010). Beyond their role in the preservation of wild species, bees play a crucial role in the pollination of agricultural crops (Winfree, 2010;Beche et al., 2022). Bees are also capable of producing a number of products such as honey, royal jelly, propolis and wax (Kanaka- Gantenbein;. ...
Introduction. Propolis is one of the products made by bees and its chemical composition depends on the region, available plant species and climatic conditions. Among the 13 types of propolis produced in Brazil, green, red and brown are the main ones. Objective. To present the pharmacological properties of Brazilian green propolis observed through experiments involving animals and humans. Methodology. Careful research of articles published from 2017 to 2022 was conducted at Pub-Med, Science direct, Embase and Scielo, focusing on the pharmacological effects of Brazilian green propolis or its constituents observed in clinical trials. Results and discussion. Published results suggest that short- or long-term administration of propolis does not cause toxic effects. Pharmacokinetic studies show that terpenes, such as artepillin C and drupanin, are the main active constituents. Conclusion. For decades the Brazilian green propolis pe used in the treatment and prevention of diseases. However more specific studies are suggested to clarify the pharmacokinetics of green propolis, to establish safe and more effective doses.
... Bees (Hymenoptera: Apoidea) are declining globally (Lerman et al. 2018, Potts et al. 2010, Russell et al. 2018, Winfree 2010) from habitat loss and degradation caused by agriculture, development, and urbanization (De Palma et al. 2015, Geslin et al. 2016, Hernandez et al. 2009). Nonetheless, green spaces in developed and urban areas may have a rich bee fauna, albeit often with a high percentage of non-native species (Droege and Shapiro 2011, Fitch et al. 2019, Gruver and CaraDonna 2021, Matteson and Langellotto 2009, Theodorou et al. 2020, Tommasi et al. 2004. ...
... With global declines of bees (Lerman et al. 2018, Potts et al. 2010, Russell et al. 2018, Winfree 2010) because of habitat loss from urbanization (De Palma et al. 2015, Geslin et al. 2016, Hernandez et al. 2009), understanding the ecological functions of bees in urban and developed environments is of increasing importance (Ayers 2021, Braman and Griffin 2022, Brant et al. 2022, da Rocha-Filho et al. 2018, Twerd and Banaszak-Cibicka 2019. The bee diversity in the ROW found during our study suggests the importance of these habitats in developed landscapes. ...
... Bees are declining globally as urbanization reduces habitats (De Palma et al. 2015, Geslin et al. 2016, Hernandez et al. 2009, Lerman et al. 2018, Potts et al. 2010, Russell et al. 2018, Winfree 2010. In these urban and developed landscapes, transmission ROW can provide habitats for bees that are otherwise lacking (Russell et al. 2005, Russo et al. 2021. ...
Our study documented the bee fauna of an overhead transmission ROW crossing through a highly developed landscape in central New Jersey. The 82 species found during our survey represent 22 percent of the 371 bees recorded in New Jersey, albeit with a high percentage (13 percent) being non-native.
... Al hablar de de polinizadores también hablamos de mariposas, moscas, escarabajos, murciélagos, aves, lagartijas, y mamíferos que juagan un papel importante en la estabilidad de distintos hábitats o para algunas plantas. Sin embargo ningún polinizador alcanza la dominancia numérica de visitar flores como las abejas, probablemente porque las abejas son dependientes de las flores en estado adulto y en estado larval dependen del néctar y el polen (Winfree, 2010). Las abejas son además, el polinizador principal de los cultivos agrícolas. ...
... Por lo general los insectos no están representados en los programas de protección. Los países que han inventariado sus insectos encontraron que al menos 10% son vulnerables o están amenazados, lo que correspondería a 95,000 especies de insectos vulnerables o amenazadas mundialmente (Winfree, 2010). En otro capítulo hablaremos más a detalle sobre el tema de la hablaremos a profundidad de la legislación mexicana que protege a las abejas. ...
El libro es más bien un manual escrito pensando en que, además de la descripción de los elementos naturales ligados a la producción de miel, se presente también un panorama completo acerca de lahistoria de la meliponicultura tanto a nivel nacional como a nivel
peninsular, y se expone también cómo la llegada de la abeja Apis mellifera, vino a complementar las técnicas de la meniponicultura local con la apicultura del viejo continente. Los capitulos abordan temas importantes como la producción de miel, características fisicoquímicas de la miel, plagas y enfermedades que afectan a las abejas, buenas practicas de manejo sanitario, importancia de la vegetación para las abejas y el efecto del uso de plaguicidas en cultivos agricolas. Todo esto acompañado de recomendaciones fundamentadas que puedan ser utiles para quienes trabajan con abejas o quienes esten interesados en el área.
... Rapid habitat loss and non-native species introduction are a by-product of colonization and imperialism resulting in the large scale extinction and extirpation of species globally (Davies 2011;Scheper et al. 2014;Sánchez-Bayo and Wyckhuys 2019). Agricultural and industrial intensification within the last two centuries have accelerated Lands 1 degradation, especially in usurped Indigenous territories; all living beings 2 , including Indigenous peoples, are displaced by such activities (Brown and Paxton 2009;Winfree 2010;Kline and Joshi 2020). The 1950s represented an acceleration for mass agricultural and industrial intensification in pursuit of lands for cash crops, reaching previously-unmanaged Lands that had provided refuges for Bee communities; this led to large reductions of biodiversity around production areas (Scheeper et al. 2014; Sánchez-Bayo and Wyckhuys 2019). ...
... Such practices, collectively "accumulation by dispossession" (Harvey 2003), result in disconnect of humans from Lands (Durkheim 1965;Fischer 2008). As cities are built and people migrate to them, other beings and habitats are disrupted and displaced, frequently entrapping human and non-human beings in small refuges dispersed across their previous home ranges (Cowie and Holland 2006;Winfree 2010;Scheper et al. 2014;Koch et al. 2019; Sánchez-Bayo and Wyckhuys 2019; Wood et al. 2019). As refugia are dispersed and destroyed, Indigenous communities are forced to either move onto reserves and outlands to maintain cultural practices or "integrate" into capitalist city-states (Crosby 2003;Beckert 2015). ...
In this conceptual paper, we argue that the assumptions behind laboratory and field studies are that chemical and compositional analysis may reveal structures unseen by means of human observation. However, replacing human observation to make it obsolete is not the purpose of science; if something can be seen, but is not measurable, that does not make it irrelevant. Although science is frequently primarily regarded as a quantitative field, we argue that qualitative data inclusion is necessary determine the consequences of research on Indigenous communities. We discuss key points, including historical and anthropocentric views of science, suggesting that Indigenous Science requires greater wisdom-based knowledge in association with traditional ecological knowledge. We introduce a new conceptual model called “Pollen Sovereignty”, a sister to Indigenous food sovereignty, to begin critical discussions around the ethics of field research and the impacts of research on the environment, land management, and Indigenous communities. That is, through simple scientific concepts, critical thought, and logic new conceptual frameworks and avenues of research, Indigenous knowledges cannot merely be coopted and reused, but respected and valued.
... Around three-quarters of solitary bee species are ground-nesting (Antoine & Forrest, 2021). The much lower prevalence of fungal or other pathogens that could destroy brood or nest provisions probably contributes to the greater frequency of ground-nesting in arid environments compared to the humid tropics (Michener, 1979;Winfree, 2010). In warm-temperate dry environments, most solitary bee species have short activity periods (sometimes only a few weeks), with usually a single generation per year and extended adult, prepupal or larval diapause (Danforth, Minckley & Neff, 2019). ...
... There are important fundamental gaps in our knowledge of bee biology (Winfree, 2010). For tropical Africa, whose bee fauna is poorly studied relative to those of other regions, these gaps are even larger. ...
Actions for ecological restoration under the Great Green Wall (GGW) initiative in the northern Sahel have been plant focused, paying scant attention to plant–animal interactions that are essential to ecosystem functioning. Calls to accelerate implementation of the GGW make it timely to develop a more solid conceptual foundation for restoration actions. As a step towards this goal, we review what is known in this region about an important class of plant–animal interactions, those between plants and flower‐visiting insects. Essential for pollination, floral resources also support insects that play important roles in many other ecosystem processes. Extensive pastoralism is the principal subsistence mode in the region, and while recent analyses downplay the impact of livestock on vegetation dynamics compared to climatic factors, they focus primarily on rangeland productivity, neglecting biodiversity, which is critical for long‐term sustainability. We summarise current knowledge on insect–flower interactions, identify information gaps, and suggest research priorities. Most insect‐pollinated plants in the region have open‐access flowers exploitable by diverse insects, an advantageous strategy in environments with low productivity and seasonal and highly variable rainfall. Other plant species have diverse traits that constrain the range of visitors, and several distinct flower types are represented, some of which have been postulated to match classical “pollination syndromes”. As in most ecosystems, bees are among the most important pollinators. The bee fauna is dominated by ground‐nesting solitary bees, almost all of which are polylectic. Many non‐bee flower visitors also perform various ecosystem services such as decomposition and pest control. Many floral visitors occupy high trophic levels, and are indicators of continued functioning of the food webs on which they depend. The resilience of insect–flower networks in this region largely depends on trees, which flower year‐round and are less affected by drought than forbs. However, the limited number of abundant tree species presents a potential fragility. Flowering failure of a crucial “hub” species during exceptionally dry years could jeopardise populations of some flower‐visiting insects. Furthermore, across Sahelian drylands, browsers are increasingly predominant over grazers. Although better suited to changing climates, browsers exert more pressure on trees, potentially weakening insect–flower interaction networks. Understanding the separate and combined effects of climate change and land‐use change on biotic interactions will be key to building a solid foundation to facilitate effective restoration of Sahelian ecosystems.
... The honey bees (Apis mellifera var. adansonii), the pollinators of plants the world over; play a crucial role for wild and cultivated plants, especially in the tropics where insect pollination is vital (Winfree, 2010;Ollerton et al., 2011). Some honey components, such as carbohydrates, water, traces of organic acids, enzymes, amino acids, and pigments, come from bees and plants, while others, such as pollen and wax, appear during honey maturation (Agwu and Okeke, 1997). ...
... A palynological study of the cultivated plants in Rawalpindi, Pakistan, was conducted by Noor et al. (2004) while in Nigerian cultivated plants with 20 different pollen morphologies have been described by Adekanmbi and Ogundipe (2006). The Moringaceae and Berberidaceae families' pollen studies were carried out by Perveen and Qaiser (2009;2010). ...
The disputed issues of higher plant taxonomy and phylogeny are greatly impacted by pollen morphology because pollen grains have clear distinctive characteristics that are typically labeled. Palynotaxonomical study of Honeybees preference plants in SouthWestern Nigeria were conducted between the months of May, 2019 and June 2021 using fresh polleniferous materials which were extracted through acetolysis methods. Results showed that ninety-two (92) plant species belonging to thirty-six (36) plant families of apicultural importance most visited by honeybees (Apis mellifera var. adansonii) were documented. At x100 magnification, thorough morphological studies were performed, and the results showed that pollen grains from plant species in the family Asteraceae were spinolous and spherical in shape; those from the Fabaceae sub-families Caesalpinoideae, Mimosoideae, and Papilionoideae, on the other hand, had a great deal of morphological diversity with variations in symmetry, position and distribution. Those of the families Malvaceae was echinate and Myrtaceae were colporate; syncolpate and prolate respectively. However, the variations above were generally reduced within species in the same genera. Tricolpate aperture type was observed in the genus Euphorbia; giving reason for their classification in the same genera. The genus Combretum was all heterocolpate, circular in shape and heteroporate. Sculpturing was psilate or scabrate and pollen shape class were sub-prolate, oblate-spheroidal or prolate spheroidal. Similar form and symmetry observed in all the species studied were reason for their classification into the same family. The study revealed that the flowering period for most of these honeybees' forage plants were between the months of October to March. Identification, propagation, cultivation, conservation, and sustainable exploitation of these honeybee (Apis mellifera var. adansonii) forage and preference plants would be beneficial in potentially increasing the efficiency of apiculture and commercial cultivation in SouthWestern Nigeria.
... In many countries, including the United States, conservation policy is based on a list of at-risk species, and recovery efforts are founded on knowing the population biology of these species. However, unlike other taxa of conservation concern like birds ( Conde et al., 2019) and butterflies (Schultz et al., 2018), for most wild bee species we do not know basic habitat and demographic information such as where females nest, how many offspring are produced per nest, or how many nests each female builds (Winfree, 2010). Even in Europe, which has one of the best studied bee faunas in the world, more than 55% of species are classified as data deficient (Nieto et al., 2014). ...
... Crouse et al., 1987). Knowing the relative contribution of different life stages to population dynamics, and their biotic and abiotic drivers, will be key for contextualizing and forecasting patterns of abundance across the landscape or assessing current population viability (Winfree, 2010). For bees, the life stage most important for bee population growth is unclear (but in one case was linked to floral resources; Crone & Williams, 2016). ...
In recent years, motivated by widespread declines in wild bees, ecologists have prioritized learning about patterns of wild bee communities across the landscape at the expense of learning about the population‐level mechanisms driving those patterns. In this essay, we seek to revitalize the tradition of studying wild bee populations in a way that both contributes key knowledge for bee conservation and builds a strong conceptual understanding of the processes underpinning bee populations. We address two widespread concerns about investing in population‐level research. First, that population‐level studies are too conceptually narrow to provide broad inference. If population‐level studies are couched in general ecological theory, then findings from a single species can be generalized to many. We highlight how wild bees would make excellent candidates for exploring five areas of general ideas in population ecology, including nutritional ecology, drivers of vital rates, phenology and voltinism, habitat selection, and movement. Second, we address the concern that methods for studying bees at the population level are too difficult to implement. Methods for conducting population‐level studies of bees—specifically, identifying living bees in the field and studying individuals throughout their life cycles—are feasible to implement at the scales appropriate for answering population‐level questions, for example, a few species at a few sites. To facilitate adoption of these ideas, we developed an online field guide (www.watchingbees.com) and a detailed methods manual. More generally, we emphasize the value of linking data‐rich pattern‐oriented approaches in ecology with an understanding of the basic biology and mechanisms that generate those patterns.
... Bees have a vital part in the food chain, as, for example, 60% of all bird species depend on insects as a food source (Morse, 1971). Being the primary pollinators of most of the world's wild plant species (Winfree, 2010), both honeybees and their "wild sisters, " the wild bees, are contributing significantly to crop yields. In particular, the manifold wild bee species are highly effective pollinators of many crops (Richards, 1996;Heard, 1999;Javorek et al., 2002;Kremen et al., 2002). ...
... In Germany, for example, roughly 50% percent of all known wild bee species either face extinction or are already extinct (Westrich et al., 2011). Yet only two out of ∼20,000 bee species are listed on the global IUCN Red List (Winfree, 2010), which classifies species at high risk of global extinction. Moreover, bee conservation usually talks about honeybees and neglects wild bee species (van Vierssen Trip et al., 2020). ...
Introduction: Significant threats to our environment tremendously affect biodiversity and related gains. Particularly wild bees actively contribute by pollinating plants and trees. Their increasing extinction comes with devastating consequences for nutrition and stability of our ecosystem. However, most people lack awareness about those species and their living conditions, preventing them to take on responsibility.
Methods: We introduce an intervention consisting of a mobile app and related project workshops that foster responsibility already at an early stage in life. Drawing on principles from multimedia learning and child-centered design, six gamified levels and accompanying nature-based activities sensitize for the importance of wild bees and their role for a stable and diverse ecosystem. A pilot evaluation across three schools, involving 44 children aged between 9 and 12, included a pre-, post-, and delayed post-test to inspect app usability and learning gains.
Results: Most children perceived the app as intuitive, engaging, and visually appealing, and sustainably benefited from our intervention in terms of retention performance. Teacher interviews following the intervention support the fit with the envisioned target group and the classroom setting.
Discussion: Taken together, the obtained evidence emphasizes the benefits of our intervention, even though our sample size was limited due to dropouts. Future extensions might include adaptive instructional design elements to increase observable learning gains.
... Floral and nesting resources are the principal local drivers acting on the recovery of bee communities in restored areas (Winfree 2010;Onuferko et al. 2018;Gruchowski-Woitowicz et al. 2022). Habitat generalists and belowground nesting bees are favored in early restoration because of the higher availability of bare soil (Hopwood 2008). ...
... Therefore, the recovery of these hymenopteran communities is essential to the restoration outcomes. Many restoration initiatives towards creating bee-friendly habitats have been implemented in agricultural landscapes, thus favoring bee colonization and crop pollination (Winfree 2010;Kremen et al. 2018). Our study underscores that restoration initiatives focusing on wild bee communities should be based on the ecological requirements of bee species found in the nearest remaining habitat patches. ...
Anthropogenic disturbances have changed the landscape structure and functioning of many ecosystems worldwide. Ecological restoration at the landscape level is important to recover degraded and destroyed ecosystems, as well as increase habitat amount and spatial connectivity, thus reestablishing biodiversity and essential ecological processes. Different local and landscape factors affect the recovery of animal communities in general, particularly bees. These insects are essential for restoration success through pollination. Considering the importance of ecological restoration at the landscape level for pollinator conservation, we systematically reviewed the influence of landscape structure on the restoration of bee communities. Our review encompassed the analysis of 18 articles based on specific criteria including the number of bee sampling units within restored areas and landscape analyses. These studies showed that habitat amount and proximity influence in different ways the bee richness, abundance, diversity, and species composition in the restored environments. We also observed that attributes linked to habitat complexity such as the availability of floral and nesting resources drive the bee species’ colonization and persistence. Our findings emphasize the necessity of designing restoration strategies considering the spatial and temporal distribution of bee species requirements on a landscape scale.
... However, surveys in North America and Europe have reported negative trends in the population of bees and other relevant pollinators (e.g. syrphid flies) during the past decades [4,5], associated with different anthropogenic drivers, such as habitat loss and fragmentation, climate change or agricultural intensification [6][7][8]. This global decline calls for developing scalable, inexpensive and efficient methods to monitor behaviour and trends of bee communities. ...
... were analysed in 69 individuals under NC treatment and 71 individuals under IS treatment. These sounds were highly variable and characterized by a large number of harmonics(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), with sharp, moderate or restricted frequency modulation (figure 1). Sound energy of the harmonics typically decreases with frequency (i.e. ...
Global pollinator decline urgently requires effective methods to assess their trends, distribution and behaviour. Passive acoustics is a non-invasive and cost-efficient monitoring tool increasingly employed for monitoring animal communities. However, insect sounds remain highly unexplored, hindering the application of this technique for pollinators. To overcome this shortfall and support future developments, we recorded and characterized wingbeat sounds of a variety of Iberian domestic and wild bees and tested their relationship with taxonomic, morphological, behavioural and environmental traits at inter- and intra-specific levels. Using directional microphones and machine learning, we shed light on the acoustic signature of bee wingbeat sounds and their potential to be used for species identification and monitoring. Our results revealed that frequency of wingbeat sounds is negatively related with body size and environmental temperature (between-species analysis), while it is positively related with experimentally induced stress conditions (within-individual analysis). We also found a characteristic acoustic signature in the European honeybee that supported automated classification of this bee from a pool of wild bees, paving the way for passive acoustic monitoring of pollinators. Overall, these findings confirm that insect sounds during flight activity can provide insights on individual and species traits, and hence suggest novel and promising applications for this endangered animal group.
This article is part of the theme issue ‘Towards a toolkit for global insect biodiversity monitoring’.
... To support biodiversity, urban green space design must be adapted to meet the needs of vulnerable wildlife species, such as native plants and bees (Baldock, 2020). To offer concrete recommendations for conservation, it is essential to understand how species interact with their environment, and to identify the species traits affected by change due to excessive surface imperviousness (Winfree, 2010). ...
... We identified five indicator species co-occurring at patches with increased availability of urban green space edges, and certain functional commonalities can be recognized. Knowing their habitat requirements and given that these species were bound to green space edges in urban areas, nest site restoration is a tool to foster urban wild bee populations locally and support their dispersal with roadside enhancements, such as wildflower patches (Winfree, 2010). In addition, creating open soil nesting structures supports a large proportion of ground-nesting bee species that are limited in their dispersal, e.g., the found Halictus rubicundus (Neumüller et al., 2022). ...
Pervasive urbanization contributes to biodiversity declines globally, and with urbanization, road densities increase , amplifying habitat degradation and landscape homogenization. However, as a major part of urban green space, roadside vegetation permeates the urban fabric and, if enhanced, can be used to support insects, such as wild bees. To analyze local and landscape-scale effects of enhanced urban roadsides on wild bee communities and to identify bee traits affected by urban filtering, we established 78 wildflower patches with a native seed mixture along five major roads in Munich (S Germany). Species-poor roadsides with regular management were used as control. During a three-year experiment, we sampled wild bees with pan traps, monitored roadside vegetation, and analyzed landscape diversity and perimeter-area ratio of green space within a radius of 500 m. We gathered information on wild bee morphological, behavioral, phenological, and foraging traits and calculated their abundance, species richness and functional dispersion. Wild bee abundance, richness and functional dispersion increased with vegetation diversity. Functional dispersion was positively correlated with landscape diversity and distance from the city center, indicating trait-based urban filtering. A fourth corner analysis revealed that small, short-lived, and univoltine bees were disadvantaged at urban roadsides. While univoltine bees were discriminated in areas of high landscape diversity, large bees prevailed in the city outskirts, and solitary bees were associated with green space edges. We conclude that enhanced roadsides contribute to urban wild bee diversity and that identifying functional groups affected by urbanization can help to draw recommendations for effective conservation.
... availability. Lastly, we underscore the significance of conducting evaluations and long-term associated host-plant species and providing suitable nesting habitat (Winfree, 2010 162 Restoring bee habitat necessitates careful consideration of both the floral and non-floral 163 resources at a site. In this section, we will discuss the considerations for planting nutritionally, 164 phenologically, and phylogenetically diverse floral resources as well as providing non-floral 165 resources and nesting sites. ...
... The conservation of native bee species is crucial for preserving, protecting, and restoring 855 diverse ecosystems (Winfree, 2010). Although prioritizing habitat restoration focused on bees 856 may differ from conventional restoration practices, adopting this approach can yield substantial 857 benefits for bee conservation (Tonietto and Larkin, 2018). ...
... As noted in various global studies, landscape heterogeneity, particularly in semi-urban regions, is essential for maintaining pollinator populations. Our findings reinforce the need for conservation efforts that focus on maintaining diverse habitats in both urban and agricultural landscapes to support the ecological functions and pollination services of leafcutter bees (Winfree 2010;Senapathi et al. 2017;Bogusch and Horák 2018). ...
The leafcutter bees, Megachile spp. (Megachilidae: Hymenoptera) serve as a significant pollinator in ecological systems. They collect leaf discs to enclose their brood cells. Nevertheless, our current understanding of using plants as nesting resources in various ecosystems in different seasons, essential for their conservation, needs to be improved. The seasonal and landscape-level alterations have significant impacts on leafcutter bees, influencing species richness, abundance, community composition and leaf foraging behaviour. This study underscores the critical role of different seasons and landscape characteristics in shaping the leaf-foraging behaviour of leafcutter bees. We noted that semi-urban areas (151 different plant species recorded with cut leaves), with their greater landscape heterogeneity and high-quality habitats, supported higher species richness and abundance of leafcutter bees. In contrast, fully urban (49 different plant species recorded with cut leaves) and intensively agricultural landscapes (85 different plant species recorded with cut leaves) posed challenges to the survival of these bees due to habitat loss and fragmentation. We also found that during early autumn, leafcutter bees emerged and constructed ephemeral nests, intensifying leaf-cutting behaviour, whereas the summer and monsoon seasons exhibited a heightened activity, with bees building seasonal nests and gathering leaf and other essential resources extensively. In winter, leafcutting ceased as these bees entered into dormant conditions, seeking shelter in their nests for insulation and protection. This study provides valuable insights into the foraging patterns and habitat preferences in different seasons of leafcutter bees, contributing to the broader understanding of pollinator ecology in changing landscapes and environments.
... Despite the crucial role of bees in maintaining the health of wild and agricultural ecosystems, recent reports indicate a decline in wild bee populations (Potts et al. 2010). Habitat loss due to deforestation, intensive insecticide use in cultivated areas, the expansion of urban areas, the introduction of exotic species that can transmit diseases and increase foraging competition with native bees, and the possible effects of climate change are key factors contributing to this decline (Winfree 2010). Habitat loss, particularly due to the expansion of urban areas, is considered the primary long-term cause of bee decline (Goulson et al. 2015). ...
Understanding the effects of urbanization on bee communities is essential for conservation and management programs for these pollinators. We investigated bee communities in two distinct land-use conditions in Mexico: one within the Bosque el Nixticuil-San Esteban-El Diente Natural Protected Area, which represents a conserved oak forest, and the other in a highly urbanized area in adjacent parks located approximately one kilometer from the conservation area in the Metropolitan Zone of Guadalajara with a population of 5.3 million. The objectives of the study were to 1) record the effects of urbanization on bee communities in terms of species richness, abundance and α and β diversity in an oak forest within a natural protected area and the adjacent urban area, and 2) identify the most susceptible bees and those that benefit from urbanization, and 3) to relate vegetation to bee communities. The results of the rarefaction analysis indicate that the protected natural area exhibited significantly higher richness and diversity than the urbanized area. Beta diversity analysis revealed a low species turnover, accompanied by a high rate of bee loss between conditions. A limited number of species demostrate an increase in abundance within urban areas, mainly Ceratina species, Augochlora smaragdina and Centris nitida. Furthermore, the richness of life history traits of bees was analysed. In all cases, the number of species decreased, with mainly non-eusocial, cavity or wood nesting, and polylectic feeding bees prevailing in the urban area. The richness and abundance of bees is related to the richness of plants, so it was expected to find more species and genera in the natural area. In conclusion, urbanization has a negative impact on the richness and diversity of bee communities, as well as on species composition.
... Increasing anthropogenic activities and urbanization continue to exacerbate this issue (Ritchie and Roser 2018 ), with the expansion of impervious surfaces, climate change, and environmental contamination threatening bees both directly and indirectly through their habitats (Winfree et al. 2009, Brain and Anderson 2020, Kelemen and Rehan 2021, Ayers and Rehan 2023. Fostering healthy environments for bees can support their populations, whether it be through ensuring access to suitable floral resources, providing abundant nesting substrates, or reducing pollutants such as pesticides or pathogens (Winfree 2010, Tonietto and Larkin 2018, Wilson and Jamieson 2019, Ayers and Rehan 2021. By examining how bees interact with their environment, including other pollinators, plants, and even their microbes (Trinh et al. 2018, Lopez-Uribe et al. 2020, Steffan et al. 2023, the relationships among many factors can be revealed to define a healthy bee habitat more holistically. ...
Aims
Wild bees foster diverse microbiota that may determine survival success of developing larvae. Here, we compare survivorship and microbial communities of Ceratina calcarata small carpenter bees reared from eggs across three treatments: maternally collected control provisions with diverse microbiota, sterile provisions, and probiotic provisions supplemented with a beneficial symbiont, Apilactobacillus kunkeei.
Methods and Results
Survival probability and adult masses differed across treatments, with the probiotic treatment resulting in highest survivorship and masses. By comparing the bacterial (16S rRNA), fungal (ITS), and plant (rbcL) communities of adults reared across treatments, we characterized distinct microbial communities across each that suggest the microbiome may be sensitive to microbial succession and competition.
Conclusions
We describe positive implications for the usage of probiotics on wild bees. Furthermore, the sensitivity of bee microbiota's relationships to their host, floral resources, and the environment suggests that holistic approaches best encapsulate the complex network of interactions between bees and their microbes.
... In Yukon, most of this service is provided by insects, including a wide variety of bees, flies, moths, butterflies, and beetles. Bees are especially effective at pollination due to their need to gather pollen to feed their offspring (Winfree 2010). Bumble bees are particularly well-suited for northern crops because of their ability to be active in cool temperatures, their wide breadth of floral choices including non-native plants, and the relatively long duration of their active season (Heinrich 2004, Leung and Forrest 2019, Weissman et al. 2021. ...
The need to follow agricultural practices that are ecologically sustainable is increasingly evident given the current crises of climate change and biodiversity loss. Various approaches to agriculture, such as agro-ecology and diversified farming systems, aim to maintain the biodiversity that provides necessary ecosystem services for the farm economy at various scales, in contrast to the ecological simplification of intensive agriculture. These approaches recognize that many native species provide vital ecosystem services and need to be conserved in agricultural landscapes.
... However, flower plants were sown in proximity of the Osmia nests in order to foster the establishment of our released population. The introduction of supplemental floral resources in cultivated fields, on the other hand, might be beneficial to both managed and wild bees and is a growing practice aimed to conserve pollinators in agricultural landscapes (Winfree, 2010;Tuell et al., 2014). However, the effectiveness of this practice is often context dependent and controversial, as introducing additional flowering plants in orchards with flowers that are less attractive to pollinators, might produce a distraction effect (Holland et al., 2015). ...
Kiwifruit has a strong dependence on insect pollinators, and yet the relatively low attractiveness of kiwi flowers to European polli-nators may lead to deficits in production. In Italy, due to the scarce efficacy of the honey bee in pollinating kiwifruit, the most used strategy to mitigate this issue is artificial pollination with mass-produced pollen, which incurs high costs and increases the risk of disease; alternative strategies are thus direly needed. The aims of this study are i) to quantify pollination deficit and pollinator contribution to kiwifruit production and quality, and ii) to investigate the release of red mason bees Osmia bicornis (L.) (synonym Osmia rufa) (Hymenoptera Megachilidae) and the use of flower strips (supporting both wild pollinators and the released red mason bees) as strategies for the improvement of kiwifruit pollination. Through manipulative experiments in 3 golden kiwifruit orchards in Northern Italy, we verified that kiwifruit production in the area was significantly improved by insect pollinators, but also suffered from pollination deficit, with average reductions of 9% in fruitlet set, 15% in final fruit set, and 30% in seed number. Our findings confirmed successful population establishment of managed O. bicornis in most sites, and analyses of pollen collected in their provisions indicated that these bees effectively gathered kiwi pollen. While the presence of O. bicornis had limited but statistically significant positive effects on fruit production and quality, the introduction of flower strips had a distraction effect on O. bicornis and other pollinators, leading to some negative consequences on the target crop. This suggests a need for careful management of floral resources to balance the benefits of supporting pollinator populations with the goal of maximizing kiwifruit production; at the same time, the introduction of managed pollinators such as O. bicornis might be especially beneficial to this crop in agroecosystems that are poor in alternative flower resources.
... Ceballos et al. (2015), and McCallum's (2015) definition may be more applicable than Barnosky et al.'s (2011) in research circles for current and predictive identification of a novel extinction event due to the inclusion of rate analysis allowing for ongoing monitoring. The benefit of drawing specific attention to extinction rates and their catalysts has been reasonably well explored in conservation literature, for example, dietary specialisation is associated with higher extinction rates (Winfree 2010). In this way, identifying populations exhibiting factors associated with accelerated extinction risk adds to the functional predictive quality of the definition; it also directs attention towards areas in which it is not too late for intervention. ...
The term ‘sixth mass extinction’ has become synonymous with the current biodiversity crisis. However, despite a general agreement that current biodiversity declines are severe, no consensus has been reached on whether this constitutes a ‘mass extinction event’, and thus, whether our current situation is comparable to the catastrophic extinction events of deep time. Here, we suggest that our inability to gauge whether the current biodiversity crisis is a mass extinction event may lie less in quantifiable evidence and more in the language used to define such events. We highlight areas of linguistic contention, vagueness and epistemic dispute, and discuss the role of post hoc decision‐making and language in shaping our understanding and communication of biodiversity loss. Our discussion raises larger questions about how we communicate science to the public, funders and other scientists, and how we use language to both shape awareness and leverage action.
... Of the more than 20,000 species of bees in the world, there are more than 5600 different species in North America, including those that are native to Canada, the USA and Mexico [31][32][33]. Most of these bee species are grouped within five families, which include the Apidae, Halictidae, Andrenidae, Megachilidae and Colletidae [34]. ...
The decline of wild bee populations in North America is worrisome. Honey bee (Apis mellifera) pathogens have been mentioned as one factor that may be implicated in these declines. This review analyses evidence of pathogen spillover from Apis mellifera to wild bee species, the mechanisms involved, the role of migratory beekeeping, the different pathogens associated with spillover cases, the impact of pathogens on wild bees, and a few strategies to mitigate the issue. Honey bee pathogens have been detected in more than 50 species within five families of bees in North American countries. Data on pathogen prevalence and phylogeny strongly indicate spillover from honey bees to wild bees, as well as spillback events. Most pathogens studied are viruses, but bacteria, fungi, and protozoa causing diseases in honey bees have been also found to replicate in wild bees and, in some cases, cause damage and shorten the lifespan of the insects. Regulated movement of hives and effective control of honey bee diseases could reduce the frequency of pathogen spillover to wild bee communities because these measures would decrease the risk of transmission. Additionally, the increased use of native bees and habitat restoration could reduce the risk of pathogen spillover from honey bees to wild bees. Studies focussing on the epidemiology and effects of pathogens on wild bee species are urgently needed to develop strategies for the optimal management of honey bees and wild bee species, to protect biodiversity and ecosystems, and to ensure adequate pollination services in North America.
... Conservation of bee communities is a key rationale for restoring barrens in the Northeast and elsewhere. Most, but not all, bee species in temperate regions have an affinity for open conditions, at least in part because of the higher density of flowers produced by herbaceous and shrub species supported in these areas (Antoine and Forrest 2021;Danforth et al. 2019;Galbraith et al. 2019;Michener 2000;Murray, Kuhlmann, and Potts 2009;Winfree 2010;Winfree, Griswold, and Kremen 2007). Many of these plant species are important host plants for bees, providing abundant nectar and pollen, the primary foods for these taxa (Fowler 2016). ...
Bees and moths are globally important pollinators. Xeric barrens in the largely mesic northeastern USA support high levels of pollinator diversity, including rare bees and moths. We investigated the response of bee vs. moth communities to abiotic and vegetation drivers in barrens across the region. We sampled local environmental conditions, vegetation, bees, and moths for 2–4 years in 19 preserves. Employing random forest analysis, we tested the role of 29 abiotic and vegetation predictors of bee vs. moth abundance, species richness, Shannon‐Wiener Index, evenness, and species composition. Variables related to climate, canopy cover, and soils were the most important predictors of abundance, diversity, and species composition for both bees and moths. Vegetation variables, such as species richness of shrubs and hostplants, were also important for bees. The direction of these relationships contrasted sharply between bees and moths: bees were more abundant and species rich in more open, sandy sites and moths the opposite. Habitat preferences for a subset of moth xeric specialists were much more similar to bees than to other moths, with a preference for open, sandy conditions. Contrasts between bees and moths in habitat preferences likely stemmed from differences in their life histories: bees rely on flowers for feeding and porous substrates for nesting, whereas most moth adults feed on flowers, but many moth caterpillars use woody plants as hosts. In sharp contrast to the results for abundance and richness, bees and moths responded similarly for the Shannon‐Wiener Index, which raises important general questions about the conservation value of these two metrics. Our results suggest that, because of differences in habitat preferences among pollinators, barrens management for both open and more closed habitats is likely to promote the highest abundance and diversity of local bee and moth pollinator communities jointly.
... While these species tend to be large, emblematic mammals, such as giant pandas and tigers, the possibility of edible insect species as flagship species and/or umbrella species protecting other natural resources deserves attention, not least because of the valuable role they have in the provision of essential ecosystem services (Yen, 2009). Yet for this to occur, taxonomic knowledge of insectswhich still lags far behind that of vertebrates and plantsneeds to improve (Winfree, 2010). There is also relatively little documented knowledge of insect species (compared with vertebrate animal and plant species) about contemporary threats and conservation and management requirements (Yen, 2012). ...
Nanozymes: The Novel Enzymes
... Additionally, in agricultural areas, bees increase the productivity and quality of fruits of many crops dependent on pollination, increasing their commercial values. [9][10][11] Therefore, this ecological role played by bees reinforces the importance of this group for maintaining ecosystems, making them instrumental in sustaining both plant and animal life. 1,2,5 In addition to pollination, another notable aspect of bee ecology is honey production, a process integral to the life cycle of some species, including the commercially better-known honeybee, Apis mellifera, and species of stingless bees. ...
The presence of microplastics in honey samples from a native Brazilian bee varied from 0.1 to 2.6 particles per mL across urban and vegetated areas.
... The impact of land-use intensity on pollinator abundance, richness, and diversity cannot be overstated. High-intensity land use, characterised by urbanisation and intensive agriculture, often leads to habitat destruction and fragmentation, negatively impacting pollinator populations [69]. ...
Declining populations of native pollinators, especially wild bees, underline the urgent need for effective monitoring within agricultural ecosystems. This study aims to (i) establish the ‘Knautia Pollinator Walk’ as an innovative pollinator monitoring method, (ii) examine the link between pollinator richness/density and land cover, and (iii) assess if specialist solitary bees indicate pollinator abundance and morphogroup richness. The approach involves surveying 500 Knautia arvensis inflorescences per site thrice per season. Observations of 11,567 pollinators across 203 taxa showed significant correlations between pollinator diversity and land use. Pollinator populations fluctuated with land cover type, increasing in open areas but decreasing or stabilising in forested and shrubby regions. Noteworthy differences in pollinator types were seen between Russia (solitary bees, small Diptera, Lepidoptera) and Sweden (bumblebees, beetles, furry Diptera). The “Knautia Pollinator Walk” shows promising signs of being an effective tool for monitoring spatiotemporal biodiversity trends. The method offers a scalable approach to pollinator monitoring, which is essential for developing conservation strategies and supporting pollinator populations.
... This application rate was chosen based on manufacturer recommendations for row crops. Because neonicotinoid levels in restoration habitats are notoriously heterogeneous and rates of persistence are dependent on other environmental variables (Felsot et al., 1998;Donnarumma et al., 2011;Sharma et al., 2014;Fletcher et al., 2018), we selected an application rate to reflect a worst-case scenario of clothianidin soil contamination in field margins or prairies recently restored from conventional agriculture; areas that are designed to attract and be a refuge for beneficial insect communities (Lagerlöf et al., 1992;Winfree, 2010). This application rate yielded soil contamination rates higher (Supplementary Table S4) than some studies in the neonicotinoid soil contamination literature (Hladik et al., 2017;Main et al., 2020). ...
The neurotoxic insecticide class of neonicotinoids has become one of the most widely used groups of pesticides globally. Their long half-lives and high water solubility increase their potential to linger and affect numerous organisms long after application. A prominent concern associated with residual contamination is the negative impact that neonicotinoids can have on beneficial arthropods such as bees and certain groups of beetles. Many studies have looked at the effects neonicotinoids have on arthropod communities in lab settings; however, comparatively few studies have looked at these groups in neonicotinoid-contaminated restored prairie habitats. These habitats are often restored from or located near agriculture and are almost ubiquitously contaminated with neonicotinoids. Our one-year manipulated field study compared native bee nesting rates and beetle community assemblages between paired clothianidin-contaminated and non-contaminated restored prairie plots. Native bee nesting probability and nesting abundance increased by 46% and 172%, respectively, in sites contaminated with clothianidin. Conversely, we observed no significant differences in beetle family assemblages, abundance, or richness between clothianidin-contaminated and control sites. These results suggest that neonicotinoid contamination of natural habitats can have numerous environmental consequences for arthropods and that these effects are not always consistent between taxa. Understanding how neonicotinoid contamination affects beneficial groups such as bees and arthropod community assemblages is crucial for characterizing the risks these chemicals pose to ecologically imperative taxa.
... Phylogenetically and functionally distant groups, such as bees and hoverflies, can play different roles in plant-pollinator interaction networks. Bees are characterized by having high per capita visitation rates and a high degree of trophic plasticity, being often able to change the plant species they use according to their environment (e.g., number of competing species or floral availability) (Klinkhamer, 2006;Waser et al., 1996;Williams et al., 2010;Winfree, 2010), and with that, the structure of plant-pollinator networks (Spiesman & Gratton, 2016). Therefore, bees might promote high interaction diversity, overall low specialization (H2), and low niche overlap. ...
... Bee abundance and richness show negative responses to drastic land use changes, but with moderate changes mixed responses can be observed; some bees show a drastic reduction in their populations, while others remain stable and even increase in disturbed sites (Winfree 2010;Winfree et al. 2009). Urbanization eliminates the original vegetation, and the remaining vegetation is substantially modified with the introduction of new plant species, in large cities there are changes in local temperature, precipitation changes, and rainfall runoff conditions are altered, in addition buildings can function as shelters or nesting sites (Frankie and Ehler 1978). ...
Mexico’s wild bee richness includes 1,800 species, however, there is a lack of studies on this group in the country. Therefore, it is of extreme importance to intensify the study on this group of insects, so this research aimed to compile an inventory of the melittofauna of Sierra de Quila, Jalisco, Mexico, to evaluate alpha diversity in different types of vegetation, and assess which of the most abundant bee species are synanthropic (organisms that live near and benefit from humans and their environmental modifications). Bees were collected and recorded over two years between 10:00 and 16:00 h, in the flora and fauna protection area of Sierra de Quila and its region of influence, using entomological nets. A total of 15,641 individuals of 233 species belonging to 66 genera and five families were recorded, of which Apidae is the best represented family with 88 species, followed by Halictidae with 54 species, Megachilidae with 49 species, Andrenidae with 24 species, and Colletidae with 18 species. Tropical dry forest showed a higher richness of wild bees than the pine-oak forest, eight species were asynanthropic and only five species were eusynanthropic. Our results show that Sierra de Quila is one of the richest areas in bee species for the state of Jalisco, making it an important area for the conservation of this group of native pollinators.
... For example, though bees and other pollinators increase yield of 75% of all major crop species [20] and a higher number of flower-visiting bee species can increase fruit set and yield [21][22][23], only 12.6% of all bee species have been found on crops and only 2% contribute >5% to crop flower visitation [24]. Hence, the vast majority of the~20 000 bee species globally [25] needs protected natural land. For most insect groups, only a small share can be expected to inhabit cropland. ...
The continuing biodiversity losses through agricultural expansion and intensification are dramatic. We argue that a mix of on- and off-field measures is needed, overcoming the false dichotomy of the land sharing-sparing debate. Protected land is essential for global biodiversity, while spillover between farmed and natural land is key to reducing species extinctions. This is particularly effective in landscapes with small and diversified fields. Focusing only on protected land fails to conserve a wealth of species, which often provide major ecosystem services such as pest control, pollination, and cultural benefits. On-field measures must minimise yield losses to prevent increased demand for food imports from biodiversity-rich regions, requiring enforcement of high social–ecological land-use standards to ensure a good life for all.
... Wild pollinators are a target group in conservation programmes across agricultural landscapes [1,2]. Due to their relevance not only for biological diversity, but also for agroecosystems and food production, their abundance and richness are often regarded as important farmland biodiversity indicators. ...
Despite the importance of pollinators to ecosystem functioning and human food production, comprehensive pollinator monitoring data are still lacking across most regions of the world. Policy-makers have recently prioritised the development of large-scale monitoring programmes for pollinators to better understand how populations respond to land use, environmental change and restoration measures in the long term. Designing such a monitoring programme is challenging, partly because it requires both ecological knowledge and advanced knowledge in sampling design. This study aims to develop a conceptual framework to facilitate the spatial sampling design of large-scale surveillance monitoring. The system is designed to detect changes in pollinator species abundances and richness, focusing on temperate agroecosystems. The sampling design needs to be scientifically robust to address questions of agri-environmental policy at the scales of interest. To this end, we followed a six-step procedure as follows: (1) defining the spatial sampling units, (2) defining and delimiting the monitoring area, (3) deciding on the general sampling strategy, (4) determining the sample size, (5) specifying the sampling units per sampling interval, and (6) specifying the pollinator survey plots within each sampling unit. As a case study, we apply this framework to the “Wild bee monitoring in agricultural landscapes of Germany” programme. We suggest this six-step procedure as a conceptual guideline for the spatial sampling design of future large-scale pollinator monitoring initiatives.
... Global evidence of wild bee declines has accumulated steadily over the last three decades. Although the conservation status for most of the world's roughly 20,000 wild bee species (Michener, 2007;Ascher and Pickering, 2017) has still not been assessed (Winfree, 2010;deMaynadier et al., 2023), the proportion of threatened species ranges from 12.5 to 45% of regional faunas among those groups that have been considered, such as the bumble bees (Cameron and Sadd, 2020;Bumble Bee Specialist Group, 2023) and a small proportion of other bee groups (NatureServe, 2023). Notably, certain bee groups, including pollen specialists with limited host plant associations, and species with larger body sizes (e.g., genus Bombus) and smaller phenological breadth (e.g., genus Andrena), appear particularly susceptible to decline (Biesmeijer et al., 2006;Bartomeus et al., 2013;Hofmann et al., 2019;Bogusch et al., 2020). ...
Introduction
Bee conservation in the US is currently hindered by challenges associated with assessing the status and trends of a diverse group of >3000 species, many of which are rare, endemic to small areas, and/or exhibit high inter-annual variationin population size. Fundamental information about the distribution of most species across space and time, thus, is lacking yet urgently needed to assess population status, guide conservation plans, and prioritize actions among species and geographies.
Methods
Using wild bee data from two public data repositories representing the contiguous US, we evaluated the availability and sufficiency of data for use in species assessments of wild bees. We also examined the number of bee species recorded in each US state and the proportion of species with recent records (2012–2021).
Results
Although efforts to monitor bees continue to grow, there remains a massive paucity of data. Exceedingly few records (0.04%)reported both sampling protocol and effort, greatly limiting the usefulness of the data. Few species or locations have adequate publicly available data to support analyses of population status or trends, and fewer than half of species have sufficient data to delineate geographic range. Despite an exponential increase in data submissions since the 2000s, only 47% of species were reported within the last decade, which may be driven by how data are collected, reported, and shared, or may reflect troubling patterns of local or large-scale declines and extirpations.
Discussion
Based on our analysis, we provide recommendations to improve the quality and quantity of data that can be used to detect, understand, and respond to changes in wild bee populations.
... The significance of native, wild bees as pollinators for crops is a subject of ongoing debate, although their importance in natural ecosystems is generally recognized [25]. Approximately 80% of flowering plants rely on pollinators for fertilization, and wild bees play a predominant role as primary pollinators in the majority of ecosystems [1,[26][27][28]. ...
Wild bees hold tremendous significance as vital natural pollinators on a global scale. Approximately 20,000 bee species have been described worldwide. They are efficient pollinators owing to their species diversity and abundance, varied floral preferences, flight times, and reliance on weather conditions. Moreover, the extent and nature of pollination services provided by wild bees differ with geographical location, landscape type, climate conditions, and floral morphology. The decline of bees can be attributed to a combination of factors, such as loss, modification, and fragmentation of habitat, pesticide utilization, climate change, and the introduction of pests and diseases. Unlike honey bees, wild bees cannot easily be cultivated or reared in artificial conditions, hence strategies are needed to protect wild bees in the field. Conservation efforts can focus on protecting and restoring their natural habitats in different types of landscapes, implementing measures in human-altered environments, and utilizing human-made tools to support their well-being.
... Beyond the burden that both parasites and viruses represent for honeybee health, increased transmission potential of viruses is a serious threat to other insect pollinators. More than 20 000 species of wild bees play critical roles in agriculture and native ecosystems [104]. Increased viral loads in honeybees in the presence of varroa may lead to undesired spillover to co-foraging insect pollinators or bee predators [51,68,75,105,106], the consequences of which for biodiversity and ecosystem functioning deserve more attention [37], as do the risks of developing new reservoirs or outbreaks of novel variants [107]. ...
Invasive vectors can induce dramatic changes in disease epidemiology. While viral emergence following geographical range expansion of a vector is well known, the influence a vector can have at the level of the host's pathobiome is less well understood. Taking advantage of the formerly heterogeneous spatial distribution of the ectoparasitic mite Varroa destructor that acts as potent virus vector among honeybees Apis mellifera, we investigated the impact of its recent global spread on the viral community of honeybees in a retrospective study of historical samples. We hypothesized that the vector has had an effect on the epidemiology of several bee viruses, potentially altering their transmissibility and/or virulence, and consequently their prevalence, abundance, or both. To test this, we quantified the prevalence and loads of 14 viruses from honeybee samples collected in mite-free and mite-infested populations in four independent geographical regions. The presence of the mite dramatically increased the prevalence and load of deformed wing virus, a cause of unsustainably high colony losses. In addition, several other viruses became more prevalent or were found at higher load in mite-infested areas, including viruses not known to be actively varroa-transmitted, but which may increase opportunistically in varroa-parasitized bees.
... The survival of both plants and bees is strongly interlinked and interdependent, especially in tropical regions where 94% of angiosperms rely on insect pollination, primarily by bees (Thapa, 2006;Potts et al., 2016;Todd et al., 2016). Honey bees (Hymenoptera: Apidae) are globally recognized for their vital role in pollinating both wild and cultivated plants (Jay, 1986;Winfree, 2010;Ollerton et al., 2011). By gathering pollen and nectar from various plant species, honey bees facilitate the pollination process (Kumar & Khan, 2022). ...
Weekly surveys of bee visiting plants in a mosaic landscape at
Merveille, near Puducherry, Southern India were conducted from
March 2018 to Feb. 2020 in order to determine a sustainable
habitat for the cavity-nesting honey bee Apis cerana Fabricius
(Hymenoptera: Apidae). A total of 145 species from 59 families
were identified as bee-visiting plants, with 46 (31.7%) providing
mainly nectar, 26 (17.9%) primarily pollen and 73 (50.4%)
providing both. The Fabaceae are the most bee-visiting family,
followed by Rubiaceae, Compositae and Euphorbiaceae. Although
trees were the most predominant growth form, herbs and some
exotics of different growth forms were also frequently visited. In
regard to the colours of the pollen loads of bees, white was the
dominant, followed by yellow with occasional orange and purple.
The study finds the need for long-term field observations on bee foraging plants in rapidly transforming mosaic landscapes.
... Además, se encuentran en grave peligro por fragmentación de hábitat y cambio de uso de suelo (Milet-Pinheiro & Schlindwein 2005). La conservación de los bosques protege a las abejas de orquídeas y el resto de las abejas nativas, que son de gran importancia para la diversidad de angiospermas dentro del ecosistema (Winfree 2010). Es necesario promover estrategias de protección para evitar la extinción o reducción de área de distribución. ...
This work is the first published synthesis about the orchid bees (Apidae: Euglossini) for Guatemala. We integrated previous data with our new collecting data and present an annotated list of 35 species, three of which are new country records for Guatemala: Eufriesea engeli Gonzalez & Griswold, 2017, Euglossa allosticta Moure, 1969, and Euglossa heterosticta Moure, 1968. For each species, we present departmental and altitudinal distribution in Guatemala, phenology (months when collected), diurnal activity (time of collecting events), and a list of chemical attractants for the males. The departments for which we found greatest species diversity are Izabal, Alta Verapaz and Suchitepéquez; however, collecting efforts were not even throughout the country. We found high species diversity in altitudes between sea level and 1000 meters. Between 1000 and 2000 meters there are somewhat fewer species and only four species were found above 2000 meters. Bees were collected throughout the year, but a greater number of species was obtained in July, September and April. Lastly, we successfully attracted male Euglossini with eight different chemical baits, among which eucalyptus oil (with cineole as an active ingredient) and scatole attracted more species.
... Deterioration of flower-rich habitats has been strongly linked with the reduction of pollinator presence in agroecosystems (Baude et al., 2016;Cole et al., 2017;Potts et al., 2010;Vanbergen et al., 2013;Winfree et al., 2009), as insect pollinators strongly depend on floral resources (Meek et al., 2002;Potts et al., 2003; van Rijn et al., 2013). On the other hand, pollinator conservation through habitat preservation or recreation in agricultural areas has been acknowledged by several authors (Isaacs et al., 2009;Scheper et al., 2013Scheper et al., , 2015Winfree, 2010) suggesting measures such as establishment of flower strips in field margins (Blaauw & Isaacs, 2014;Carvell et al., 2007;Karamaouna et al., 2019Karamaouna et al., , 2022Kati et al., 2021) or inside the crop (Campbell et al., 2013;Carvalheiro et al., 2012), cover crops and intercropping (Beyer et al., 2020a;Cole et al., 2015Cole et al., , 2020Pywell et al., 2005). ...
Legumes provide nutritious floral resources for bees thus are commonly considered for use in schemes to enhance pollinators in agroecosystems. In particular, legume landraces are important elements in practices towards sustainable agriculture. Differences in flower morphology and nectar may affect the attraction of pollinators. The aim of the present study was to investigate possible differences in pollinator attraction between a Vicia faba L. landrace and a commercial variety and to indicate differences in floral characteristics and nectar quality traits which can be associated with bee visits. To assess this, floral morphological trait measurements and chemical analysis using high‐resolution mass spectrometry‐based non‐targeted screening of the flower nectar were carried out and bee visits on faba bean flowers were recorded. Floral traits that contributed to the separation of the two accessions were ‘intensity of streaks’ and ‘extent of anthocyanin colouration’ on standard petal which were more pronounced in the landrace. All nectar traits examined contributed to the separation of the two V. faba accessions. Chemical substances such as amino acids and sugars which are important for bee nutrition are differentially increased in the landrace compared with the commercial variety. The landrace attracted more bee genera ( Apis , Anthophora , Eucera ) and bee visits compared with the commercial variety (only Eucera ) supporting that the floral and nectar differences between the accessions of the same plant species are important to bees. The well‐fitting interrelation of the landrace flowers and bee visits can have possible implications in agricultural practices such as crop breeding for pollinator friendly varieties through selecting floral traits, improvement of foraging resources for pollinators in agroecosystems and subsequently food production. Exploitation of the V. faba landrace in agroecological schemes to support conservation of flora and fauna genetic resources in situ should be considered also for the benefit of future food stability and security.
This chapter is a comprehensive exploration of the pivotal. Beginning with an emphasis on the significance of quantifying local floral resources, this chapter highlights the essential role of understanding their composition, distribution, and abundance in maintaining healthy ecosystems and supporting pollinators. The scope broadens as the chapter transitions to the mapping of floral resources on larger scales, extending from global to regional assessments, providing valuable insights into the broader landscape of these crucial resources. To comprehensively understand floral resources, it explores a wide array of variables (basic, abiotic, and biotic), offering a global framework for grasping the multifaceted nature of floral resources. The integration of open data and adherence to the FAIR principles are crucial for advancing our knowledge of floral resources. Ensuring that data are findable, accessible, interoperable, and reusable is integral to informed decision-making and effective resource management. Software tools play pivotal roles in facilitating the assessment and management of floral resources, aiding researchers and conservationists in optimizing their efforts and enhancing resource utilization. New technologies are also a focus, with discussions on the potential of remote sensing at various scales and the utility of software models in supporting decision-making, especially at the crop plot level. Continuous monitoring is emphasized as an essential aspect of floral resource assessment. Vigilance is required to adapt to changing conditions and to ensure the sustained protection of these invaluable resources. Conservation efforts take centre stage as the chapter explores European programmes and the crucial role of protected areas in serving as socioecosystems for pollinator conservation. Effective strategies for the protection of floral resources, the potential impacts of global warming on plant–pollinator interactions, and the contribution of protected areas to the well-being of floral resources and pollinators are also discussed. This chapter serves as a comprehensive and insightful resource, emphasizing the critical role of floral resource assessment and conservation in safeguarding biodiversity and ecological equilibrium. It is a valuable guide for researchers, conservationists, and policymakers committed to building a sustainable future for floral resources and the ecosystems that they support.
Native seed mixes are widely available to create pollinator habitat. One approach to understand the efficacy of pollinator seed mixes is to compare them to species found in high‐quality natural areas. Using plant species presence data from published lists, we compared weekly blooming richness between 196 seed mixes explicitly designed to support pollinators and 102 prairie remnants from eight states across the Midwest. Remnants had greater forb richness compared to mixes and had at least twice the blooming richness per week. Seed mixes included low proportions of species that bloomed in the spring (0–13% of species), whereas about 28% of remnant forbs bloomed before June. There was a sharp phenological blooming peak for mixes due to the vast majority of species blooming in late July through August, whereas remnants had greater phenological evenness across the growing season. We then investigated all observed early blooming plant species to identify the species best suited to alleviate the dissimilar spring blooming characteristics. We compiled 10 species characteristics that reflected species' feasibility for cultivation and restoration and blooming attributes, identifying a group of underutilized and commercially unavailable species. Pollinator seed mixes should facilitate blooming availability for the duration of the growing season to meet pollinator foraging requirements.
The impact of the programmatic use of larvicides for mosquito control on native stingless bees (e.g., Apidae, Meliponini) is a growing concern in Australia due to heightened conservation awareness and the growth of hobbyist stingless bee keeping. In Australia, the two most widely used mosquito larvicides are the bacterium Bacillus thuringiensis var. israelensis (Bti) and the insect hormone mimic methoprene (as S-methoprene). Each has a unique mode of action that could present a risk to stingless bees and other pollinators. Herein, we review the potential impacts of these larvicides on native Australian bees and conclude that their influence is mitigated by their low recommended field rates, poor environmental persistence, and the seasonal and intermittent nature of mosquito control applications. Moreover, evidence suggests that stingless bees may display a high physiological tolerance to Bti similar to that observed in honey bees (Apis mellifera), whose interactions with B. thuringiensis-based biopesticides are widely reported. In summary, neither Bti or methoprene is likely to pose a significant risk to the health of stingless bees or their nests. However, current knowledge is limited by regulatory testing requirements that only require the use of honey bees as toxicological models. To bridge this gap, we suggest that regulatory testing is expanded to include stingless bees and other nontarget insects. This is imperative for improving our understanding of the potential risks that these and other pesticides may pose to native pollinator conservation.
Large-scale agroecosystems are often a mosaic of different annual and perennial crops, semi-natural habitats, and natural habitats within various land-use systems. In these systems, pest and beneficial insect population patterns increase and decline at varying degrees within and across crops. Different biotic and abiotic interactions within these systems often influence these patterns, such as landscape configurations, climatic conditions, and on-farm practices. Pollination by insects is a critical ecosystem service necessary to produce most crops, including those providing essential nutrients for food security. When managed appropriately, agricultural landscapes can provide a habitat for many insect species. However, we are amid an unprecedented decline in managed and wild pollinator populations, diversity, and health worldwide. Large-scale agroecosystems dominate North American, European, and selected other rural landscapes worldwide, covering roughly 137 million ha in the United States alone. This anthropogenic intensification reduces natural or semi-natural land harboring wild pollinators and diverse floral resources. While there are many forms of pollinators, most pollination ecologists would agree that bees (Hymenoptera: Anthophila) are recognized as the most predominant pollinators for most plants. This chapter will dive into the relationship between pollinators and the crops they pollinate in large-scale agroecosystems (including honey bees, wild bees, and non-bee pollinators), benefits to pollinators from crops and benefits to crops from bees, and integrated pest and pollinator management (IPPM) systems. Implementing landscape-scale conservation strategies, such as promoting habitat restoration, reducing pesticide use, creating floral resources, and enhancing connectivity, can help support diverse and resilient pollinator populations.
Habitat loss is a primary driver of global biodiversity decline, negatively impacting many species, including native bees. One approach to counteract the consequences of habitat loss is through restoration, which includes the transformation of degraded or damaged habitats to increase biodiversity. In this review, we survey bee habitat restoration literature over the last 14 years to provide insights into how best to promote bee diversity and abundance through the restoration of natural landscapes in North America. We highlight relevant questions and concepts to consider throughout the various stages of habitat restoration projects, categorizing them into pre-, during-, and post-restoration stages. We emphasize the importance of planning species- and site-specific strategies to support bees, including providing floral and non-floral resources and increasing nest site availability. Lastly, we underscore the significance of conducting evaluations and long-term monitoring following restoration efforts. By identifying effective restoration methods, success indicators, and areas for future research, our review presents a comprehensive framework that can guide land managers during this urgent time for bee habitat restoration.
Ground-nesting bees are susceptible to disturbances that affect foraging resources, vegetation structure and soil characteristics. We studied the effects of 12 invasive alien plant species on environmental variables and directly on ground-nesting bees to reveal their specific importance. We sampled bees along transects; flowers, vegetation, bare ground and litter in quadrats, as well as soil characteristics. Our results suggested that plant invasion reduced overall and flowering plant richness and positively affected the height of native vegetation. However, this did not affect ground-nesting bees’ abundance or species richness. Although we found invaded plots to have altered soil chemical characteristics compared to control plots, there was no correlation between soil characteristics and ground-nesting bees. The large explanatory potential of the random factors suggests that there were large differences in the abundance and species richness of ground-nesting bee species among the different habitat types and before and during the flowering of the invasive species. Although our study lacked a direct sampling of nesting bees, our results show the adverse effects of plant invasion on foraging and some nesting characteristics of ground-nesting bees. Future studies should put effort into the investigation of the number of nest holes and additional soil characteristics to get a better picture of the effects of plant invasion on ground-nesting activity.
The health of bees can be assessed through their microbiome, which serves as a biomarker indicating the presence of both beneficial and harmful microorganisms within a bee community. This study presents the characterisation of the bacterial, fungal, and plant composition on the cuticle of adult bicoloured sweat bees ( Agapostemon virescens ). These bees were collected using various methods such as pan traps, blue vane traps and sweep netting across the northern extent of their habitat range. Non‐destructive methods were employed to extract DNA from the whole pinned specimens of these wild bees. Metabarcoding of the 16S rRNA, ITS and rbcL regions was then performed. The study found that the method of collection influenced the detection of certain microbial and plant taxa. Among the collection methods, sweep net samples showed the lowest fungal alpha diversity. However, minor differences in bacterial or fungal beta diversity suggest that no single method is significantly superior to others. Therefore, a combination of techniques can cater to a broader spectrum of microbial detection. The study also revealed regional variations in bacterial, fungal and plant diversity. The core microbiome of A. virescens comprises two bacteria, three fungi and a plant association, all of which are commonly detected in other wild bees. These core microbes remained consistent across different collection methods and locations. Further extensive studies of wild bee microbiomes across various species and landscapes will help uncover crucial relationships between pollinator health and their environment.
Current ecological communities are in a constant state of flux from climate change and from species introductions. Recent discussion has focused on the positive roles introduced species can play in ecological communities and on the importance of conserving resilient ecosystems, but not how these two ideas intersect. There has been insufficient work to define the attributes needed to support ecosystem resilience to climate change in modern communities. Here, I argue that non‐invasive, introduced plant species could play an important role in supporting the resilience of terrestrial ecosystems to climate change. Using examples from multiple taxonomic groups and ecosystems, I discuss how introduced plants can contribute to ecosystem resilience via their roles in plant and insect communities, as well as their associated ecosystem functions. I highlight the current and potential contributions of introduced plants and where there are critical knowledge gaps. Determining when and how introduced plants are contributing to the resilience of ecosystems to climate change will contribute to effective conservation strategies.
Foraging behavior frequently plays a major role in driving the geographic distribution of animals. Buzzing to extract protein-rich pollen from flowers is a key foraging behavior used by bee species across at least 83 genera (these genera comprise ~58% of all bee species). Although buzzing is widely recognized to affect the ecology and evolution of bees and flowering plants (e.g., buzz-pollinated flowers), global patterns and drivers of buzzing bee biogeography remain unexplored. Here, we investigate the global species distribution patterns within each bee family and how patterns and drivers differ with respect to buzzing bee species. We found that both distributional patterns and drivers of richness typically differed for buzzing species compared to hotspots for all bee species and when grouped by family. A major predictor of the distribution, but not species richness overall for buzzing members of four of the five major bee families included in analyses (Andrenidae, Halictidae, Colletidae and to a lesser extent, Apidae) was the richness of poricidal flowering plant species, which depend on buzzing bees for pollination. As poricidal plant richness was highest in areas with low wind and high aridity, we discuss how global hotspots of buzzing bee biodiversity are likely driven by both biogeographic factors and plant host availability. Whilst we explored global patterns with State-level data, higher resolution work is needed to explore local level drivers of patterns, but from a global perspective, buzz-pollinated plants clearly play a greater role in the ecology and evolution of buzzing bees than previously predicted.
In North American conifer forests, a variety of federally initiated thinning programs are implemented to restore pre‐European settlement forest structures, but these changes may impact ecosystem function via impacts on sensitive biotic communities. Across the wildland–urban interface of the Front Range region of Colorado, agencies associated with the Collaborative Forest Landscape Restoration Program (CFLRP) have implemented thinning treatments across thousands of hectares of ponderosa pine forest; here we leverage these treatments as an experimental framework to examine thinning effects on a pollinator community. We measured variation in forest structure and sampled bee community assemblages using multiple methods (trapping and netting) to compare bee biodiversity and patterns of floral visitation by bees (bee–flower networks) between mechanically thinned stands that were 3–10 years after treatment and nonthinned stands. Three key findings emerged: (1) Native bee abundance, richness, and diversity were 120%, 53%, and 37% greater, respectively, in thinned stands. In addition, nestedness, richness, and abundance of bee–flower interactions were all substantially higher in thinned stands, and there was increased functional redundancy in bee assemblages after thinning. (2) Structural equation modeling indicated that variation in temperature and floral abundance were mediated by canopy openness and correlated with bee richness and abundance, thereby indirectly driving variation in bee–flower interactions. (3) Four floral species (Penstemon virens, Cerastium arvense, Erysimum capitatum, and Geranium caespitosum) were identified as key connectors in bee–flower interaction networks, though these were not necessarily the most abundant flowering plants. Our analyses indicate that native bee α‐diversity and bee–flower interactions positively responded to thinning treatments, and these effects were indirectly driven by canopy removal. We conclude that CFLRP treatments have conservation value for native bee communities. Further monitoring is warranted to evaluate the longevity of these effects.
Ecosystem health and agricultural wealth in North America depend on a particular invertebrate fauna to deliver pollination services. Extensive losses in pollinator guilds and communities can disrupt ecosystem integrity, a circumstance that today forces most farmers to rely on honey bees for much fruit and seed production. Are North America's invertebrate pollinator faunas already widely diminished or currently threatened by human activities? How would we know, what are the spatiotemporal scales for detection, and which anthropogenic factors are responsible? Answers to these questions were considered by participants in a workshop sponsored by the National Center for Ecological Analysis and Synthesis in October of 1999, and these questions form the nucleus for the papers in this special issue. Several contributors critically interpret the evidence for declines of bee and fly pollinators, the pollination deficits that should ensue, and their economic costs. Spatiotemporal unruliness in pollinator numbers, particularly bees, is shown to hinder our current insights, highlighting the need for refined survey and sampling designs. At the same time, two remarkable studies clearly show the long-term persistence of members of complex bee communities. Other authors offer new perspectives on habitat fragmentation and global warming as drivers of pollinator declines. Bees and lepidopterans are contrasted in terms of their natural genetic variation and their consequent resilience in the face of population declines. Overall, many ecologists and conservation biologists have not fully appreciated the daunting challenges that accompany sampling designs, taxonomy, and the natural history of bees, flies, and other invertebrate pollinators, a circumstance that must be remedied if we are to reliably monitor invertebrate pollinator populations and respond to their declines with effective conservation measures.
Stingless bees are an abundant group of insects, but how much of an economic role do they have to play in world agriculture and could they be better managed to pollinate crops? Whilst these questions remain to be fully answered, the indications are that they could be useful and relatively low maintenance pollinators.
These proceedings contain papers on insect conservation biology that are classified under 3 themes: (1) the current status of insect conservation, and major avenues for progress and hindrances (6 papers); (2) insects as model organisms in conservation biology (6 papers); and (3) future directions in insect conservation biology (6 papers).
Plant-pollinator systems inherently possess wide variation that limits the applicability of surveys on population dynamics or diversity. Stable habitats are scarcely studied, whereas dynamics in unprotected habitats are less predictable or more compromised by exotic organisms (Apis, in the case of bee surveys). An extensively replicated, long-term study of orchid-bees (Euglossini) was made in protected tropical moist forest in Panama. Over 47,000 bees were recorded in 124 monthly censuses employing 1952 counts. No aggregate trend in abundance occurred (from 1979 to 2000), although four individual species declined, nine increased, 23 showed no change, and species richness was stable. No rare or parasitic species showed decreasing trends, while the most common of the set of bee species studied gradually declined. Biodiversity therefore increased. Recorded variability included 300% (fourfold) differences in bee abundance among years, and changes in species abundance up to 14-fold. Surveys in dry and wet seasons (N = 17 and 18 years, 29 and 31 species, respectively) indicated no numerical changes in the bee assemblage over 21 years. El-Niño climatic events led to brief increases in bee abundance. This detailed survey is deconstructed to assess sampling rigor and strategies, particularly considering the recorded local differences within a single forest. Year-to-year shifts in bee abundance for three tropical and five temperate bee censuses were comparable. In short studies (2-4 years) and during longer studies (17-21 years), 59 species that included solitary, social, and highly social bees had mean abundances that varied by factors of 2.06 for temperate bees and 2.16 for tropical bees. "Normal" bee populations commonly halved or doubled in 1-yr intervals. Longer term data are only available for the tropics. Stochastic variation and limitations of monitoring methods suggest that minimum series of four years (i.e., three intervals) of several counts during the active season may demonstrate genuine trends. Longer term, continuous studies are still needed for meaningful insights on pollinator population shifts in nature.
These proceedings contain papers on insect conservation biology that are classified under 3 themes: (1) the current status of insect conservation, and major avenues for progress and hindrances (6 papers); (2) insects as model organisms in conservation biology (6 papers); and (3) future directions in insect conservation biology (6 papers).
Modern ecological research often involves the comparison of the usage of habitat types or food items to the availability of those resources to the animal. Widely used methods of determining preference from measurements of usage and availability depend critically on the array of components that the researcher, often with a degree of arbitrariness, deems available to the animal. This paper proposes a new method, based on ranks of components by usage and by availability. A virtue of the rank procedure is that it provides comparable results whether a questionable component is included or excluded from consideration. Statistical tests of significance are given for the method. The paper also offers a hierarchical ordering of selection processes. This hierarchy resolves certain inconsistencies among studies of selection and is compatible with the analytic technique offered in this paper.
As the need increases for sound estimates of impending rates of animal and plant species extinction, scientists must have a firm grounding in the qualitative and quantitative methods required to make the best possible predictions. Extinction Rates offers the most wide-ranging and practical introduction to those methods available. With contributions from an international cast of leading experts, the book combines cutting-edge information on recent and past extinction rates with treatments of underlying ecological and evolutionary causes. Throughout, it highlights apparent differences in extinction rates among taxonomic groups and places, aiming to identify unresolved issues and important questions. Written with advanced undergraduate and graduate students in mind, Extinction Rates will also prove invaluable to researchers in ecology, conservation biology, and the earth and environmental sciences.
Important breakthroughs have recently been made in our understanding of the cognitive and sensory abilities of pollinators: how pollinators perceive, memorise and react to floral signals and rewards; how they work flowers, move among inflorescences and transport pollen. These new findings have obvious implications for the evolution of floral display and diversity, but most existing publications are scattered across a wide range of journals in very different research traditions. This book brings together for the first time outstanding scholars from many different fields of pollination biology, integrating the work of neuroethologists and evolutionary ecologists to present a multi-disciplinary approach. Aimed at graduates and researchers of behavioural and pollination ecology, plant evolutionary biology and neuroethology, it will also be a useful source of information for anyone interested in a modern view of cognitive and sensory ecology, pollination and floral evolution.
The biological diversity of our planet is being depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding depression an inevitable consequence for many species. This textbook provides a clear and comprehensive introduction to the importance of genetic studies in conservation. The text is presented in an easy-to-follow format with main points and terms clearly highlighted. Each chapter concludes with a concise summary, which, together with worked examples and problems and answers, emphasise the key principles covered. Text boxes containing interesting case studies and other additional information enrich the content throughout, and over 100 beautiful pen and ink portraits of endangered species help bring the material to life.
Filter strips or buffers are areas of grass or other perennial herbaceous vegetation established along waterways to remove contaminants and sediments from agricultural field runoff. In the heavily cultivated regions of the Midwestern United States, these buffer zones established under the Farm Bill provide important habitat for wildlife such as butterflies. The question of how the landscape context of these plantings influences their use has not been adequately researched. We used multiple regression and Akaike's Information Criteria to determine how habitat width and several landscape-level factors (i.e., landscape composition [total herbaceous cover, amount of developed area, and amount of wooded cover] and configuration [herbaceous edge density]) influenced the abundance and diversity of the butterfly community using filter strips in southwestern Minnesota, USA. Habitat-sensitive butterfly abundance and all richness and diversity measures were positively correlated with filter-strip width. Butterfly abundance was negatively associated with the amount of developed areas (cities, towns, and roads) within the area of a 1-km radius (3.14 km²) surrounding the sites. Percentage of wooded cover in the landscape was an important variable explaining individual species abundance, although the direction of the relationship varied. Our finding that landscape context influences butterfly use of filter strips highlights the importance of landscape-level approaches to wildlife conservation in agroecosystems.
Observations of uniquely marked females of the solitary, twig-nesting bee, Osmia bruneri, were conducted under greenhouse conditions to test several predictions of sex-ratio and parental-investment theory. In support of Fisher's (1958) theory, we found that the observed sex-ratio of progeny in this dimorphic species did not differ from that expected on the basis of average male and female weights. Investment patterns also exhibited a seasonal component: female parents produced more female than male offspring early in the nesting season but reversed this pattern later. Interfemale variability was large for all nesting parameters examined. Neither female-parent size nor the rate at which females completed cells was significantly related to several estimates of parent fitness. Parent-offspring heritability for size was also low. We found no evidence to support the hypothesis that progeny sex-ratios are influenced by maternal condition. Variance in progeny sex-ratios was large, but the population sex-ratio probably departs frequently from the equilibrium value. The results marginally support Kolman's (1960) prediction of large variance in progeny sex-ratios in large panmictic populations. We conclude that variability among females in investment patterns and variability in size among progenies are probably maintained by such factors as resource heterogeneity and the shape of the adult survivorship curve.
Evolutionary and population dynamics models suggest that the migration rate will affect the probability of survival in fragmented landscapes. Using data for butterfly species in the fragmented British landscape and in immediately adjoining areas of the European continent, this paper shows that species of intermediate mobility have declined most, followed by those of low mobility whereas high-mobility species are generally surviving well. Compared to the more sedentary species, species of intermediate mobility require relatively large areas where they breed at slightly lower local densities. Intermediate mobility species have probably fared badly through a combination of metapopulation (extinction and colonization) dynamics and the mortality of migrating individuals which fail to find new habitats in fragmented landscapes. Habitat fragmentation is likely to result in the non-random extinction of populations and species characterized by different levels of dispersal, although the details are likely to depend on the taxa, habitats and regions considered.
Changes in flower-visiting insect populations or communities that result from human impacts can be documented by measuring spatial or temporal trends, or by comparing abundance or species composition before and after disturbance. The level of naturally occurring variation in populations and communities over space and time will dictate the sampling effort required to detect human-induced changes. We compiled a set of existing surveys of the bee faunas of natural communities from around the world to examine patterns of abundance and richness. We focused on a subset of these studies to illustrate variation in bee communities among different sites and within sites over different spatial and temporal scales. We used examples from our compilation and other published studies to illustrate sampling approaches that maximize the value of future sampling efforts. Existing studies suggest that bee faunas are locally diverse, highly variable in space and time, and often rich in rare species. All of these attributes indicate that intense sampling among sites and years will be required to differentiate changes due to specific impacts from the natural dynamics of populations and communities. Given the limits on time and funding for studying bees, approaches that maximize information for effort must be sought for future studies. Reliable information on population and community changes may be gleaned from examining "functional groups" rather than entire faunas. Regardless of the purpose of the study, standardized sampling protocols using replicated designs will increase the value of data. Standardization permits statistical testing of changes in bee populations and communities, and allows for rigorous comparison between studies.
How can rapidly growing food demands be met with least adverse impact on nature? Two very different sorts of suggestions predominate in the literature: wildlife-friendly farming, whereby on-farm practices are made as benign to wildlife as possible (at the potential cost of decreasing yields); and land-sparing, in which farm yields are increased and pressure to convert land for agriculture thereby reduced (at the potential cost of decreasing wildlife populations on farmland). This paper is about one important aspect of the land-sparing idea - the sensitivity of future requirements for cropland to plausible variation in yield increases, relative to other variables. Focusing on the 23 most energetically important food crops, we use data from the Food and Agriculture Organisation (FAO) and the United Nations Population Division (UNPD) to project plausible values for 2050 for population size, diet, yield, and trade, and then look at their effect on the area needed to meet demand for the 23 crops, for the developing and developed worlds in turn. Our calculations suggest that across developing countries, the area under those crops will need to increase very considerably by 2050 (by 23% under intermediate projections), and that plausible variation in average yield has as much bearing on the extent of that expansion as does variation in population size or per capita consumption; future cropland area varies far less under foreseeable variation in the net import of food from the rest of the world. By contrast, cropland area in developed countries is likely to decrease slightly by 2050 (by 4% under intermediate projections for those 23 crops), and will be less sensitive to variation in population growth, diet, yield, or trade. Other contentious aspects of the land-sparing idea require further scrutiny, but these results confirm its potential significance and suggest that conservationists should be as concerned about future agricultural yields as they are about population growth and rising per capita consumption.
It has long been assumed that inbreeding depression in haplodiploid organisms is low due to their ability to purge genetic load in haploid males. It has been suggested that this low genetic load could facilitate the evolution of inbreeding behaviors driven by local mate competition in hymenopteran parasitoids. I have examined inbreeding depression in haplodiploids in two ways. First I show that an outbreeding haplodiploid wasp Uscana semifumipennis (Hymenoptera: Trichogrammatidae) suffers substantial inbreeding depression. Longevity was 38% shorter, fecundity was 32% lower, and sex ratio was 5% more male for experimentally inbred wasps when compared to outbred controls. There were interactions between size and both fecundity and sex ratio for inbred wasps that were not seen for outbred individuals. Second, an analysis of data from the literature suggests that when inbreeding is experimentally imposed on populations, haplodiploid insects and mites as a group do suffer less from inbreeding depression than diploid insects, although substantial inbreeding depression in haplodiploid taxa does exist. The meta-analysis revealed no difference in inbreeding depression between gregarious haplodiploid wasps, which are likely to have a history of inbreeding, and solitary haplodiploid species, which are assumed to be primarily outbred.
Pollination by bees and other animals increases the size, quality, or stability of harvests for 70% of leading global crops. Because native species pollinate many of these crops effectively, conserving habitats for wild pollinators within agricultural landscapes can help maintain pollination services. Using hierarchical Bayesian techniques, we synthesize the results of 23 studies – representing 16 crops on five continents – to estimate the general relationship between pollination services and distance from natural or semi-natural habitats. We find strong exponential declines in both pollinator richness and native visitation rate. Visitation rate declines more steeply, dropping to half of its maximum at 0.6 km from natural habitat, compared to 1.5 km for richness. Evidence of general decline in fruit and seed set – variables that directly affect yields – is less clear. Visitation rate drops more steeply in tropical compared with temperate regions, and slightly more steeply for social compared with solitary bees. Tropical crops pollinated primarily by social bees may therefore be most susceptible to pollination failure from habitat loss. Quantifying these general relationships can help predict consequences of land use change on pollinator communities and crop productivity, and can inform landscape conservation efforts that balance the needs of native species and people.
Genetic modification (GM) of crops has been accompanied by concerns of environmental impact, including effects to beneficial organisms such as bees. Currently, most commercial GM crops are modified for pest and/or herbicide resistance. Transgenes such as Bt may be expressed in pollen, resulting in exposure to bees. However, studies to date indicate that crops transformed with genes coding for Bt proteins will not harm bees. Herbicide resistant crops are not likely to pose direct toxicity effects to bees; yet, greater weed control in herbicide resistant crops may be responsible for a lower bee abundance in these crops than non-transformed crops. Reduced pesticide use associated with insect resistant GM crops, and reduced tillage that is possible with herbicide tolerant crops, could be beneficial to bee populations compared to conventional agriculture. Risk of GM crops to bees should be assessed on a case-by-case basis in relation to feasible alternatives.
The populations of farmland birds in Europe declined markedly during the last quarter of the 20th century, representing a severe threat to biodiversity. Here, we assess whether declines in the populations and ranges of farmland birds across Europe reflect differences in agricultural intensity, which arise largely through differences in political history. Population and range changes were modelled in terms of a number of indices of agricultural intensity. Population declines and range contractions were significantly greater in countries with more intensive agriculture, and significantly higher in the European Union (EU) than in former communist countries. Cereal yield alone explained over 30% of the variation in population trends. The results suggest that recent trends in agriculture have had deleterious and measurable effects on bird populations on a continental scale. We predict that the introduction of EU agricultural policies into former communist countries hoping to accede to the EU in the near future will result in significant declines in the important bird populations there.
Native birds may have been underestimated as pollinators of the New Zealand flora due to their early decline in abundance and diversity on the mainland. This paper reconsiders the relative importance of birds and insects as pollinators to eight native flowering plants, representing a range of pollination syndromes, on two offshore island refuges. Experimental manipulations were made on five of these plant species to assess the relative effectiveness of bird and insect visitors as pollinators. In addition, foraging behaviour and the respective morphologies of flowers and visitors were measured at all eight plants to identify the main pollinators. The experimental measures showed that percentage fruit set was significantly higher in flowers exposed to birds than flowers from which birds were excluded in all manipulated plants. The observational measures revealed that for six of the flowering species (Sophora microphylla, Vitex lucens, Pittosporum crassifolium, Pittosporum umbellatum, Pseudopanax arboreus and Dysoxylum spectabile) the endemic honeyeaters were most likely to meet the conditions necessary for successful pollination. For the remaining two species (Metrosideros excelsa and Geniostoma ligustrifolium) the contribution by honeyeaters and insects to pollination was equivalent. The results suggest that the role of the endemic honeyeaters in pollination of the New Zealand flora, and the subsequent regeneration of native forest ecosystems, should be important considerations in ecosystem management.
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.
The mechanism of sex determination assumed widespread in parthenogenetically arrhenotokous Hymenoptera is that of single locus complementary sex determination (CSD). Functionally sterile diploid males are produced under CSD and generate a genetic load, the cost of which increases with inbreeding. We quantify diploid male production (DMP, proportion of diploid individuals that are male) using a morphological criterion (adult fresh weight) and genetical (microsatellite DNA) markers in a communal, sexually size-dimorphic bee, Andrena scotica, which inbreeds. Male genotypes suggested a DMP of 0.003. The inbreeding coefficient, f, was significantly positive (+0.165), equivalent to 44% of matings being among full sibs (predicted DMP of 0.11). We hypothesize three non-mutually exclusive explanations to account for the large difference between the low observed (in males) and high expected (derived from f for females) DMP: (i) multilocus CSD, (ii) «sex allele signalling» tied to mate selection, and (iii) sperm selection within mated females. The costs of inbreeding through DMP are apparently low in A. scotica.
This study examines the species richness of bees and flower visiting wasps in seasonal neotropical habitats in Costa Rica. A total of 9231 individuals were netted at flowers. These represented 192 species of bees and 138 species of wasps. Over 50% of the bee individuals were eusocial Apidae, but there were only 12% of the bee species. There was less dominance among the wasp families. Most of the species in both groups were uncommon: 50% of the bee species were represented by fewer than 8 individuals, and over 50% of the wasp species had only 1 or 2 individuals. Previous comparisons of the species richness of bees in tropical and temperature areas have been complicated by different sample sizes and a lack of distinguishing within- and between-habitat diversity components. Here, comparisons are made of within-habitat species richness for structurally similar habitats. The within-habitat species richness of bees was higher in tropical forests than in the temperate forests previously described. The tropical grassland had lower bee species richness, and it is postulated that the coevolutionary history of a habitat is an important component of bee diversity. The higher species richness of tropical forests was correlated with the abundance and diversity of animal-pollinated plants. Tropical bees were not more temporally specialized despite the longer flowering seasons, so diversity and temporal specialization were not correlated. The average flight season of tropical species was 3 times longer than that reported for bees in most temperate areas, and the turnover in species was also similar. Seasonality was correlated with the degree of species' sociality: eusocial bees were essentially aseasonal. Most seasonal bee species were encountered in the dry season. Flower visiting wasps were much more diverse in the tropical habitats than reported for temperate habitats, and they overlap with bees in resource use. Many other taxa also fed at flowers, and such diversity among competitors may be a factor in limiting bee diversity in the tropics.
Conversion of land to grow crops, raise animals, obtain timber, and build cities is one of the foundations of human civilization. While land use provides these essential ecosystem goods, it alters a range of other ecosystem functions, such as the provisioning of freshwater, regulation of climate and biogeochemical cycles, and maintenance of soil fertility. It also alters habitat for biological diversity. Balancing the inherent trade-offs between satisfying immediate human needs and maintaining other ecosystem functions requires quantitative knowledge about ecosystem responses to land use. These responses vary according to the type of land-use change and the ecological setting, and have local, short-term as well as global, long-term effects. Land-use decisions ultimately weigh the need to satisfy human demands and the unintended ecosystem responses based on societal values, but ecological knowledge can provide a basis for assessing the trade-offs.
Bees are most abundant and diverse in certain warm temperate, xeric regions of the world, especially the Mediterranean basin, the Californian region, and coniguous desertic areas. Other warm temperate xeric areas, like central Chile or the western part of southern Africa, have less rich faunas. Arid tropical regions, as well as tropical savannas, have poor bee faunas. For example, the southern margin of the Sahara and northern Australia are not rich in bees, in spite of the nearness of the former to the Mediterranean basin with past nondesert connections to the Mediterranean and the contiguity of the latter with the large warm temperate Australian faunal area. Equatorial savannas like those of east Africa are rather poor in bees. Warm temperate, mesic areas, such as those of eastern North America, Europe, or the southern Brazilian to Argentina region of South America, also have rich faunas, although less so than do the Mediterranean basin and southwestern United States. Perhaps because of its small area, the climatically equivalent region in South Africa (largely in Natal) has a fauna that is best described as depauperate tropical, with certain temperate elements, but without great richness. The moist tropics vary considerably in abundance and diversity of bees. In the Americas, they are almost or quite as rich as are the warm temperate mesic areas, but in Africa the fauna is far poorer, although richer than that of the Oriental region. There is a single Paleotropical bee fauna, richest in Africa and progessively smaller as one goes eastward across southern Asia to New Guinea, the Solomon Islands, and northeastern Australia. The poverty of the Oriental faunal region is shown by the number of genera and subgenera--89 compared to 175 in sub-Saharan Africa and 315 in the Neotropics (including temperate areas). Thus unlike many groups which abound in the tropics, bees attain their greatest abundance in warm temperate areas. It is especially in such areas, principally xeric ones, that certain presumably archaic groups of bees have survived, and it is likely that various groups originated in such areas.
This book is based on the proceedings of a symposium with the theme 'Conserving Europe's bees', organized by the International Bee Research Association and the Linnean Society and held in London, UK, on 6-7 April 1995. The first 5 chapters consider the environmental requirements of bees (Apoidea) and how these can be provided by conservation efforts. Man-made habitats may provide substitutes for threatened or destroyed natural habitats; for example, sand and gravel pits may provide habitats originally found within the floodplains of wild river systems.