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Effects of Introduced Bees on Native Ecosystems
Abstract
s Abstract Bees are generally regarded as beneficial insects for their role in pol-lination, 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 conse-quences 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 disrup-tion 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 or-ganisms. 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.
... However, to date, Russo (2016) recorded 80 bee species introduced out of their native range (Fig. 1). Among these, Apis mellifera (L.) and Bombus terrestris (L.) are the two species that have been the focus of attention (Geslin et al., 2017;Mallinger et al., 2017;Goulson, 2003). These two social and domesticated species have mostly been introduced either to produce honey (for Apis mellifera) or to improve pollination services to crops (Aizen et al., 2020), sometimes doing more harm than good (Aizen et al., , 2019Sáez et al., 2014). ...
... These two social and domesticated species have mostly been introduced either to produce honey (for Apis mellifera) or to improve pollination services to crops (Aizen et al., 2020), sometimes doing more harm than good (Aizen et al., , 2019Sáez et al., 2014). Of course, not all 80 alien species described by Russo (2016) have become invasive, but the literature report many examples of deleterious consequences of the introduction of bees outside their native range (Aizen et al., 2019(Aizen et al., , 2020Geslin et al., 2017;Mallinger et al., 2017;Traveset and Richardson, 2014;Goulson, 2003). ...
... For example, Russo (2016) determined that 11 out of 80 species could positively affect native ecosystems, but no review on these effects exists to date. Of course, fieldwork and experiments to estimate impacts are costly (Goulson, 2003), but they provide valuable information for estimating impacts (e.g. see Díaz et al., 2021;Geslin et al., 2020). ...
... two species that have been the focus of attention (Geslin et al., 2017;Mallinger et al., 2017;Goulson, 2003). These two social and domesticated species have mostly been introduced either to produce honey (for Apis mellifera) or to improve pollination services to crops (Aizen et al., 2020), sometimes doing more harm than good (Aizen et al., , 2019Sáez et al., 2014). ...
... These two social and domesticated species have mostly been introduced either to produce honey (for Apis mellifera) or to improve pollination services to crops (Aizen et al., 2020), sometimes doing more harm than good (Aizen et al., , 2019Sáez et al., 2014). Of course, not all 80 alien species described by Russo (2016) have become invasive, but the literature report many examples of deleterious consequences of the introduction of bees outside their native range (Aizen et al., 2019(Aizen et al., , 2020Geslin et al., 2017;Mallinger et al., 2017;Traveset and Richardson, 2014;Goulson, 2003). ...
... For example, Russo (2016) determined that 11 out of 80 species could positively affect native ecosystems, but no review on these effects exists to date. Of course, fieldwork and experiments to estimate impacts are costly (Goulson, 2003), but they provide valuabl e information for estimating impacts (e.g. see Díaz et al., 2021;Geslin et al., 2020). ...
Because of their importance as pollinators of wild and cultivated plants, little concern has been paid to alien bees when entering a new ecosystem. Hence, approximately 80 alien bee species worldwide have spread outside their native ranges. Here, we explored the main impacts of alien bees on native bees through competition for food or nesting resources, interference, pathogen spillover, and genetic contamination. Implications for native bee conservation are also discussed. In addition, in this chapter, we developed a particular focus on the first alien bee that colonised Europe, Megachile sculpturalis. We emphasised the main knowledge gaps and important trends for future research. Finally, avenues for managing alien bee species and preventing their introduction are provided.
... Several reviews of the interactions between managed and introduced bees and native bees have been produced in the last 20 years ( Geslin et al., 2017 ;Goulson, 2003 ;Mallinger et al., 2017 ;Paini, 2004 ;Wojcik et al., 2018 ). These reviews increasingly suggest that managed honey bees and bumblebees can have substantial impacts on wild bee fitness as a result of resource competition. ...
... As is typical in reviews on bees or pollinators, studies involving honey bees ( Apis mellifera ) dominate the literature ( Arena and Sgolastra, 2014 ;Goulson, 2003 ;Iwasaki and Hogendoorn, 2021a ;Mallinger et al., 2017 ), followed by bumblebees ( Bombus spp.). Studies with interactions that involved Apis composed 78% (n = 178) of all study outcomes. ...
... Similar to other reviews ( Dicks et al., 2021 ;Goulson, 2003 ;Mallinger et al., 2017 ;Paini, 2004 ), studies from North America and Europe dominated publications on bee competition. With respect to other regions, states in Oceania (Australia, New Zealand, New Caledonia, Hawaii, Pacific nations) and South America had significant representation, east and central Asian countries were under-represented, and Africa was the most under-represented continent. ...
Worldwide, the use of managed bees for crop pollination and honey production has increased dramatically. Concerns about the pressures of these increases on native ecosystems has resulted in a recent expansion in the literature on this subject. To collate and update current knowledge, we performed a systematic review of the literature on the effects of managed and introduced bees on native ecosystems, focusing on the effects on wild bees. To enable comparison over time, we used the same search terms and focused on the same impacts as earlier reviews. This review covers: (a) interference and resource competition between introduced or managed bees and native bees; (b) effects of introduced or managed bees on pollination of native plants and weeds; and (c) transmission and infectivity of pathogens; and classifies effects into positive, negative, or neutral. Compared to a 2017 review, we found that the number of papers on this issue has increased by 47%. The highest increase was seen in papers on pathogen spill-over, but in the last five years considerable additional information about competition between managed and wild bees has also become available. Records of negative effects have increased from 53% of papers reporting negative effects in 2017 to 66% at present. The majority of these studies investigated effects on visitation and foraging behaviour. While only a few studies experimentally assessed impacts on wild bee reproductive output, 78% of these demonstrated negative effects. Plant composition and pollination was negatively affected in 7% of studies, and 79% of studies on pathogens reported potential negative effects of managed or introduced bees on wild bees. Taken together, the evidence increasingly suggests that managed and introduced bees negatively affect wild bees, and this knowledge should inform actions to prevent further harm to native ecosystems.
... No positive or negative effects have been reported for either non-native species of Chelostoma in North America (Russo 2016). However, there are potential consequences that could result from these accidental introductions (Goulson 2003, Russo et al. 2021. One concern would be whether the non-native species harbor any pests or diseases that could spread to native Chelostoma, particularly given that eight of the nine native North American species of Chelostoma occur in the west . ...
... However, since both introduced bee species have only been found in residential areas so far in Montana, these potential effects may only be relevant in urban habitats and garden settings for now. Though a challenging topic to address (Goulson 2003), more empirical research is needed on whether and how the establishment of non-native bees impacts native plant and pollinator biodiversity. ...
The megachilid bees of the genus Chelostoma Latreille, 1809 in Montana, U.S.A., are reviewed. Two Palearctic species, Chelostoma (Foveosmia) campanularum (Kirby, 1802) and Chelostoma (Gyrodromella) rapunculi (Lepeletier, 1841), are reported for the first time from Montana. The Montana specimens represent a range expansion from southeastern Michigan for C. campanularum and from northeastern Illinois for C. rapunculi. These collections appear to represent an established local population for C. campanularum with specimens from multiple dates, years, and locations in Bozeman, Montana; specimens of C. rapunculi have only been found in one location and year. The habitat, distribution, and potential ecological impacts of establishment of these two non-native species in Montana are discussed. An identification key to the Chelostoma of Montana is provided.
... Invasion by non-native pollinators can significantly affect native pollinators and the plants they visit, both native and introduced (Goulson 2003;Winter et al. 2006). In this line of work, the bees (Apoidea) have attracted attention, because at least five possible effects are attributed to them: (a) competition with native floral visitors for the floral resource, (b) competition with native organisms for nesting sites, (c) (Muñoz and Cavieres 2008). ...
... Error bars are ±2 SE, and the asterisks represent significant differences (P < 0.05). RNE: relative neighbor effect index transmission of pathogens to native organisms, (d) changes in native plant seed production, and (e) weed pollination (Goulson 2003). ...
... In addition, North Dakota is the largest honey bee producer in the United States (US Department of Agriculture 2020). Native bumble bees are the most similar group of bees to European honey bees in morphology and life history and are most likely to be impacted by dense introductions of a competing species that may alter bumble bee production and behavior (Goulson andSparrow 2009, Thomson 2004). ...
... However, we find no evidence of investigations into direct honey bee relationships with native bees in the greater Northern Great Plains region. Evidence of competitive effects and transmission of parasites and pathogens from honey bees to wild bees warrants increased understanding of these relationships, particularly in this region of elevated honey bee colony density (Goulson 2003, Goulson and Sparrow 2009, Herbertsson et al. 2016, Thomson 2004). ...
... Algunos estudios mencionan que puede originarse un gran riego al introducirse especies de abejorros exóticos (Freitas et al., 2009;Goulson, 2003aGoulson, , 2010Morales, 2007), como transmisión de enfermedades, competencia por espacio, comida y establecimiento e hibridación. ...
En el presente trabajo de investigación se determinó la incidencia poblacional del abejorro Bombus ephippiatus en la comunidad de Agua del Sauco, en el municipio de Techaluta de Montenegro. Para ello, se colectaron 392 insectos, de los cuales 372 son abejorros de la especie Bombus ephippiatus y 20 corresponden a otro insecto. Todas las poblaciones de abejorros se encontraron pecoreando. La incidencia poblacional de reinas de abejorros aumentó en el mes de julio, con el mayor pico en los meses de agosto y marzo, lo que nos da una ventana más amplia para la reproducción de abejorros en cautiverio.
... For instance, Liang et al. found that urbanization selects for plants with radial flower morphology, which may particularly benefit from pollination provided by generalists. Additionally, generalists and managed bees' strong preference for exotic flowering plants may bring invading problems (Goulson 2003). In tropical cities, where pollinator diversity is habitually high and urbanization is heavily occurring, keystone pollination interactions and associated ecosystem functions would vanish if urbanization-driving decreases in richness continue to happen. ...
... Com evidência dos impactos da abelha exótica na comunidade nativa em vários estudos (Goulson, 2003;Traveset & Richardson, 2006) (Levine et al., 2003;MacDougall & Turkington, 2005). ...
A abelha exótica Apis mellifera L., conhecida por sua eficácia na polinização em climas tropicais, é amplamente utilizada em sistemas agrícolas de diversas culturas, bem como na produção de mel, geleia real e própolis, entre outros produtos. Essa espécie adaptou-se bem e está distribuída por todo o território nacional. O objetivo deste estudo foi comparar quantitativamente a espécie exótica Apis mellifera L. com outras espécies de abelhas nativas na mesma área de forrageio. As coletas foram realizadas na Fazenda Experimental de Ciências Agrárias da Universidade Federal da Grande Dourados/MS, em uma área que apresenta uma diversidade de paisagens, incluindo cultivares agrícolas e áreas em processo de restauração. As coletas foram feitas a cada 30 dias, entre as 8:00hs e as 16:15hs, no período de 12 meses, de forma ativa, utilizando redes entomológicas. As plantas com flores foram observadas e as abelhas visitantes foram capturadas, anestesiadas e sacrificadas em câmara mortífera contendo acetato de etila. Posteriormente, no laboratório, elas foram identificadas em relação ao menor nível taxonômico possível. Durante os 12 meses de avaliação, a espécie exótica Apis mellifera L. foi a mais frequente em 10 dos meses avaliados. Sua abundância geral acima de 70% reafirmou sua prevalência quantitativa em relação às abelhas nativas nas áreas avaliadas. Diversos fatores podem ter contribuído para esse resultado, como a interferência humana que altera o ambiente, favorecendo espécies generalistas; o cultivo de monoculturas que beneficiam abelhas com comportamento eusocial como a A. mellifera; um grande número de indivíduos coletores na colônia e um sistema eficiente de comunicação. Portanto, a abelha exótica pode suplantar as ações das abelhas nativas em determinadas regiões e, possivelmente, suprimi-las em outras, já que dominam por saturação a fonte de alimento na área de forrageio devido ao expressivo número de indivíduos.
... Over 83 bee species have established outside of their native ranges worldwide and at least 40 species have established in North America alone (Cane 2003, Russo 2016, Gibbs and Dathe 2017, Martins et al. 2017). Non-native species can have detrimental effects on native ecosystems, yet the consequences of non-native bees are generally unknown, especially for unintentionally introduced species (Goulson 2003, Russo 2016. Some non-native bee species may be well-equipped to navigate harsh, urban landscapes, with a number of non-native species recorded exclusively in urban environments (Russo 2016, Portman et al. 2019. ...
... This phenomenon could be driven by species that are introduced into cities through human activities, for example international commerce and urban beekeeping (Egerer & Kowarik, 2020). Following an introduction, a species' diet breadth, nesting behaviour and thermal tolerance might further facilitate its establishment in cities. Generalist species with strong preferences for exotic flowering plants, cavity nesters, as well as species with thermal tolerance that matches the urban conditions, are usually good urban invaders (Goulson, 2003;Hamblin et al., 2017). However, it is worth noticing that non-native pollinators may exacerbate conservation risks to native wild species by competition for floral resources, nesting sites or transmission of parasites and pathogens (Fitch et al., 2019). ...
Urbanization is increasing worldwide, with major impacts on biodiversity, species interactions and ecosystem functioning. Pollination is an ecosystem function vital for terrestrial ecosystems and food security; however, the processes underlying the patterns of pollinator diversity and the ecosystem services they provide in cities have seldom been quantified. Here, we perform a comprehensive meta‐analysis of 133 studies examining the effects of urbanization on pollinators and pollination. Our results confirm the widespread negative impacts of urbanization on pollinator richness and abundance, with Lepidoptera being the most affected group. Furthermore, pollinator responses were found to be trait‐specific, with below‐ground nesting and solitary Hymenoptera, and spring flyers more severely affected by urbanization. Meanwhile, cities promote non‐native pollinators, which may exacerbate conservation risks to native species. Surprisingly, despite the negative effects of urbanization on pollinator diversity, pollination service measured as seed set is enhanced in non‐tropical cities likely due to abundant generalists and managed pollinators therein. We emphasize that the richness of local flowering plants could mitigate the negative impacts of urbanization on pollinator diversity. Overall, the results demonstrate the varying magnitudes of multiple moderators on urban pollinators and pollination services and could help guide conservation actions for biodiversity and ecosystem function for a sustainable future.
... Our results showed that most of flowering plant species were self-compatible in the alpine grasslands (Table S12) and the seed sets of fly-pollinated plant species (e. g. S. japonica ) increased in the plot close to the rapeseed (Fig. 4 and Table S12). Honey bees can appear as competitors when they are foraging, which can increase visitation fidelity of some pollinators, such as bumble bees and flies, which in turn causes decreased heterospecific pollen transfer and increased conspecific pollen transfer, resulting in When the pollinators of native plant species are transformed from more efficient bumble bees to less efficient honey bees, the reproductive success of these native plant species can be decreased (Goulson 2003). Thus, those bumble bee-pollinated plant species that have been visited frequently by honey bees (G. ...
The global expansion for massively introduced managed species has profoundly impacted biodiversity and ecosystem functions. However, it is unclear how introduced pollinators and mass-flowering crops simultaneously affect the structure and function of pollination networks. Here, we conducted field experiments to investigate the ecological impacts of introduced honey bee (Apis mellifera) during the flowering period of a mass-flowering crop (Brassica rapa var. oleifera) on plant-pollinator interaction networks and reproductive performance of wild plants in 48 alpine grasslands. We showed that the spillover of introduced honey bees had weak effects on the pollinator communities. In addition, honey bee spillover strengthened the pollination network structure’s stability and improved plant communities’ pollination function. These effects can be observed when the introduced honey bees and mass-flowering plants coexist in the alpine grasslands, highlighting the positive effects of honey bee spillover on the pollination-limitation alpine ecosystem.
... Some introduced bees though are now widely recognised to have negative impacts on the ecosystem that include the competition with native species for nesting sites and floral resources, and the introduction of foreign pathogens (Goulson, 2003;Russo, 2016). ...
The present study aimed to characterise the bacterial, fungal and parasite gut community of the invasive bee Megachile sculpturalis sampled from native (Japan) and invaded (USA and France) regions via 16S rRNA and ITS2 amplicon sequencing and PCR detection of bee microparasites. The bacterial and fungal gut microbiota communities in bees from invaded regions were highly similar and differed strongly from those obtained in Japan. Core amplicon sequence variants (ASVs) within each population represented environmental micro-organisms commonly present in bee-associated niches that likely provide beneficial functions to their host. Although the overall bacterial and fungal communities of the invasive M. sculpturalis in France and the co-foraging native bees Anthidium florentinum and Halictus scabiosae, were significantly different, five out of eight core ASVs were shared suggesting common environmental sources and potential transmission. None of the 46 M. sculpturalis bees analysed harboured known bee pathogens, while microparasite infections were common in A. florentinum, and rare in H. scabiosae. A common shift in the gut microbiota of M. sculpturalis in invaded regions as a response to changed environmental conditions, or a founder effect coupled to population re-establishment in the invaded regions may explain the observed microbial community profiles and the absence of parasites. While the role of pathogen pressure in shaping biological invasions is still debated, the absence of natural enemies may contribute to the invasion success of M. sculpturalis.
... al., 2009). In addition, the increasingly widespread use of managed bees may have negative effects on wild bee populations (Goulson, 2003;Paini, 2004). ...
Mutualisms between plants and their floral visitors sustain not only plant diversity, but also the diversity of an estimated 350, 000 animal species, mainly various insects, birds and mammals. Wild bees represent the most important group of pollinator insects because they play a key role in agriculture, pollinating almost all crop varieties. However, they are increasingly at risk of local and even global extinction. Climate change and habitat loss are affecting all major aspects of the biology of insects that pollinate plants in both natural and agricultural communities. Understanding network structure and its underlying causes are essential parts of any study of biodiversity and its responses to disturbances, yet it is a conceptual and methodological challenge to address these problems in highly diversified communities with thousands of interactions. Plant–pollinator communities are
typically composed of a high number of plant species and an even greater number of pollinator species.
... Thus, when revisiting Lopezaraiza-Mikel et al.'s (2007) dataset we found considerable intraspecific variation in the quantity of balsam pollen transported on the bodies of the two commonest pollinator species, A. mellifera and B. pascuorum. A. mellifera and B. pascuorum are well known as generalist species in plant-visitor networks (Goulson, 2003;Valido et al., 2019;Arroyo-Correa et al., 2020), and they visit many plant species. However, our results show that this generalization is not constant among individuals of the same species, rather there is substantial variation. ...
• Pollination networks have long been studied by quantifying plant-flower visitor species interactions. Despite making considerable contributions, this ignores important steps of pollen movement from anthers to receptive stigmas and neglects the intraspecific variation of the interacting partners. Addressing specialization and niche partitioning regarding heterospecific pollen transport and transfer, is fundamental to untangle the mechanisms behind contrasts seen in the impact of alien species on native communities. • We used two well-sampled datasets on pollen-transport and pollen-transfer networks to test how intraspecific variation in interaction specialisation affects invaded pollination networks. We considered different levels of biological organization: from species- to individual-based networks. • We found significant intraspecific variation in the pollen loads and pollen deposition of the invasive plant Impatiens glandulifera; thus only a few individual pollinators and plant stigmas carried large amounts of alien pollen grains, potentially functioning as super-spreaders driving the invading process. Consequently, most individuals carried only a few, or no alien pollen at all, possibly buffering the negative effects of invasive plants at the population and community levels. • Node and structural specialization were higher for individual-based and pollen-transfer networks, suggesting a lack of dominant, highly generalist links when downscaling from pollen-transport to pollen-transfer, and from species to individual-based networks. • The high specialization, selectiveness and niche partitioning of plants, pollinators and their interaction revealed at the different stages of the pollination process and across distinct levels of biological organization, suggest important mechanisms associated with the (re) organization of population niches. Moreover, these mechanisms provide a promising approach towards a more comprehensive understanding of the dynamics of invasion biology from population to community and ecosystem functioning.
... Attracting a greater amount and diversity of pollinators can be advantageous for plants that share them. The benefits would come from increased pollination stability, as reliance on one or few exclusive pollinator species implies greater risks of pollination limitation in case of environmental fluctuations affecting pollinator abundance or foraging behaviour (Goulson 2003). ...
Acknowledging species interactions is essential for managing diversity in complex agricultural systems. To understand the neighbouring plant effect on flower number and size, we performed a greenhouse experiment with paired pots in three treatments: focal plant (common bean/courgette) with conspecific neighbour, heterospecific neighbour or empty pot. Common beans without neighbours produced more flowers than when accompanied. Common bean with conspecific neighbours produced more flowers than with heterospecific neighbours, with larger standard petals. Courgettes with heterospecific neighbours had flowers with deeper corollas than with conspecific neighbours. To understand effects on visitation and production, we performed a field experiment comparing courgette monoculture, common bean monoculture and three intercroppings, varying the crop ratio. Species composition of floral visitors differed significantly between monoculture and intercropping. The six plots (6/21) with highest diversity were intercropping. Intercropping courgette and common bean can change floral morphology and alter plant–pollinator interactions in the agroecosystem, enhancing pollinator diversity.
... Article mellifera and many social stingless bees, there are differences in life-history traits that require characterization of the exposure and effects of pesticides in representative local stingless species (Almeida et al. 2021;Cham et al. 2019;Lima et al. 2016). This is especially relevant if we consider that A. mellifera represents a threat to native species in neotropical ecosystems where it has been introduced (Goulson 2003). ...
The decline of insect pollinators is a significant concern within the current biodiversity crisis. The paradox between the benefits that these animals represent to humans and the evidence of human activities driving their extinction calls for the urgent protection of bees. To address the role of chemical pollution in this scenario, we assessed the acute toxicity as well as four biomarker responses (cholinesterase, glutathione S‐transferase, catalase, and lipid peroxidation) elicited by dietary 24‐hour exposure to three insecticides (malathion, imidacloprid, and fipronil) on the stingless neotropical bee Tetragonisca angustula and the honeybee Apis mellifera. Malathion was the most toxic substance to both species, with 48‐hour LD50s of 0.25 ng/bee to A. mellifera and 0.02 ng/bee to T. angustula. Fipronil was also highly toxic and presented a similar toxicity to both species, with 48‐hour LD50s of 0.5 ng/bee (A. mellifera) and 0.4 ng/bee (T. angustula). Imidacloprid had the lowest acute toxicity with a 48‐hour LD50 of 29 ng/bee for A. mellifera, while T. angustula tolerated exposure higher than 35 ng/bee. Apparent biomarker responses were observed in bees of both species that survived exposure to higher concentrations of malathion (cholinesterase inhibition) and fipronil (increased lipid peroxidation). Our results suggest that specific sensitivity to insecticides varies greatly among compounds and pollinator species but the use of different representative species can facilitate the prioritization of substances regarding their risk to pollinators. Further research is necessary to better characterize the risk that pesticides represent in neotropical agricultural landscapes. This article is protected by copyright. All rights reserved. Environ Toxicol Chem 2023;00:0–0.
... Early seasonal emergence, generalist or polylectic foraging strategies, high adaptability under adverse environmental conditions in a range of habitats, and their great phenological flexibility are the most critical invasive features. After its commercial introduction, it was determined that this species is invasive, can spread into new areas, and may disturb local ecology (Goulson, 2003;Dafni, Kevan, Gross, & Goka, 2010). Competition with native organisms for nest sites and floral resources (Hingston & McQuillan, 1998), the transportation of pathogens and parasites (Goka, Okabe, Yoneda, & Niwa, 2001), hybridization with wild species (Ings, Ings, Chittka, & Rasmont, 2010) and change of natural pollination systems (Hanley & Goulson, 2003) are major problems that caused by the invasion and the increase in the population of introduced bumblebee in the new locations. ...
... This phenomenon could be driven by species that are introduced into cities through human activities, for example international commerce and urban beekeeping (Egerer & Kowarik, 2020). Following an introduction, a species' diet breadth, nesting behaviour and thermal tolerance might further facilitate its establishment in cities. Generalist species with strong preferences for exotic flowering plants, cavity nesters, as well as species with thermal tolerance that matches the urban conditions, are usually good urban invaders (Goulson, 2003;Hamblin et al., 2017). However, it is worth noticing that non-native pollinators may exacerbate conservation risks to native wild species by competition for floral resources, nesting sites or transmission of parasites and pathogens (Fitch et al., 2019). ...
Urbanisation is increasing worldwide, with major impacts on biodiversity, species interactions and ecosystem functioning. Pollination is an ecosystem function vital for terrestrial ecosystems and food security, however, the processes underlying the patterns of pollinator diversity and the ecosystem services they provide in cities have seldom been quantified. Here, we present a comprehensive meta-analysis, using 133 studies, on the effects of urbanisation on pollinator diversity and pollination. Our results confirm the widespread negative effects of urbanisation on pollinator diversity, particularly of Lepidoptera. Additionally, pollinator responses were found to be trait-specific, with below ground nesting, solitary, and spring flyers more severely affected from urbanisation. Meanwhile, cities promote a greater diversity of non-native pollinators, which may exacerbate conservation risks to native ones. Surprisingly, despite the negative effects of urbanisation on pollinator diversity, pollination services in cities are enhanced and mediated by the high flower visitation rates of abundant generalists and managed pollinators. We highlight that the richness of local flowering plants could mitigate the negative effects of urbanisation on pollinator diversity. Overall, the results demonstrate the varying magnitudes of multiple moderators on urban pollinators and pollination service provision and could help guide conservation actions for biodiversity and ecosystem function for a sustainable future.
... Further studies are required to optimize management and targeted application of solitary bees, especially ground nesting species (Cane, 1997;Mader et al., 2010;Leonard and Harmon-Threatt, 2019;Nelson et al., 2022), for blueberry pollination. Precautions must be taken when considering honey bees and alternative managed bees outside of their native ranges, as they can become invasive and detrimental to native flora and/or entomofauna, or even for crop pollination (Goulson, 2003;Russo, 2016;Geslin et al., 2017b;Morales et al., 2017;Aizen et al., 2019Aizen et al., , 2020LeCroy et al., 2020;Russo et al., 2021). Managing bees within their native range can also be detrimental to wild entomofauna by competing for floral resources or nesting habitats, spreading pests and pathogens, eroding genetic diversity, and disrupting local adaptations by hybridization between native and commercial lines (Fürst et al., 2014;Lindström et al., 2016;Mallinger et al., 2017;Seabra et al., 2019;Bartomeus et al., 2020;Russo et al., 2021). ...
Highbush blueberry (Vaccinium spp.) is a globally important fruit crop that depends on insect-mediated pollination to produce quality fruit and commercially viable yields. Pollination success in blueberry is complex and impacted by multiple interacting factors including flower density, bee diversity and abundance, and weather conditions. Other factors, including floral traits, bee traits, and economics also contribute to pollination success at the farm level but are less well understood. As blueberry production continues to expand globally, decision-aid technologies are needed to optimize and enhance the sustainability of pollination strategies. The objective of this review is to highlight our current knowledge about blueberry pollination, where current research efforts are focused, and where future research should be directed to successfully implement a comprehensive blueberry pollination decision-making framework for modern production systems. Important knowledge gaps remain, including how to integrate wild and managed pollinators to optimize pollination, and how to provide predictable and stable crop pollination across variable environmental conditions. In addition, continued advances in pesticide stewardship are required to optimize pollinator health and crop outcomes. Integration of on- and off-farm data, statistical models, and software tools could distill complex scientific information into decision-aid systems that support sustainable, evidence-based pollination decisions at the farm level. Utility of these tools will require multi-disciplinary research and strategic deployment through effective extension and information-sharing networks of growers, beekeepers, and extension/crop advisors.
... Invasive Apis and Bombus species are appreciated for their pollinator services in both natural and managed ecosystems, but there is also a growing concern about their impact on native species. Invasive bees have the potential to compete with native species for floral resources and nest sites, disrupt plant-pollinator networks, reduce reproductive success for native plants, and displace native pollinators (Goulson 2003;Paini 2004;Aizen et al. 2009;Stout & Morales 2009;Russo 2016;Ackerman 2021, Garibaldi et al. 2021. In Puerto Rico, the Africanized honeybee Apis mellifera was first reported in 1994, and now all feral colonies on the island are classified as Africanized honeybees (Cox 1994;Rivera-Marchand et al. 2012;Galindo-Cardona et al. 2013). ...
Insular pollination systems are more extinction-prone and vulnerable to invasive species than mainland ones. They often have plants with reproductive mechanisms allowing for self-compatibility and low species-rich communities of pollinators. Here, we document different reproductive traits of the tropical tree Guaiacum sanctum on two insular populations with contrasting pollinator assemblages: Guánica in Puerto Rico with alien honeybees and Mona Island where honeybees do not occur. Using field observations and pollination experiments, we evaluated pollinator species richness, visitation rates, breeding system, and the fitness of selfed- vs. crossed-progenies. We found that flowers are pollinated by insects on both islands, but while the species richness of pollinators was higher on Mona, the visitation rates were considerably higher in Guánica where trees are almost exclusively visited by the introduced Apis mellifera. Flowers are not apomictic, and autogamy is negligible indicating that pollinators are required to set fruits. Outcrossing yielded nearly twice the number of fruits and seeds than selfing and these differences were consistent between populations, which might reflect early acting inbreeding depression, partial self-incompatibility, or differences in resource allocation between selfed and outcrossed fruits. Our combined results suggest that the substantial reduction in pollinator visitors in areas dominated by A. mellifera may add an additional level of vulnerability to these threatened populations. Although reproductive fitness is higher in Guánica, mostly due to the pollination services provided by A. mellifera, this population may be more susceptible to environmental changes and large-scale disturbances affecting pollinator abundance given the reduced diversity of flower visitors.
... The most notable of these orders is Hymenoptera, because it contains bees (Hymenoptera: Apoidea), which are considered the most abundant and proficient pollinators. All bee species require pollen as a source of protein and, with the exception of a few species, pollen is the only source of protein in a bee's diet (Goulson 2003, Michner 2007. Most bee species actively pollinate flowers with the exception of cleptoparasitic species. ...
... The Indian continent is home to a diverse range of medicinal plants, the majority of which may be found as wild plants in the forests of hills and plains [12]. Disruptions to the natural ecosystems of these plants as a result of anthropogenic behaviour and the introduction of invasive species have resulted in a dramatic reduction in the population of these valuable plant species, and many of these species are now classified as uncommon, critically rare, or endangered [15]. Also known as Safed Musli, Chlorophytum borivilianum Santapau and Fernandez is a common medicinal plant of assorted Ayurvedic value. ...
... Certain plants attracted proportionately more honey bees. Honey bees are not native to the US, are domesticated, and are managed for agricultural purposes (Goulson, 2003). Goals of pollinator conservation efforts can vary, and attention on efforts that focus on honey bees may undercut native bee conservation (Colla & MacIvor, 2017). ...
Growing public awareness of pollinator declines has led to an increase in gardening for pollinators, particularly bees. In most regions of the United States a better understanding of the plants that support abundant and species rich bee communities will help urban pollinator conservation programs. To address this, we compared the relative attractiveness of 23 native Pacific Northwest plant species to bees. We performed timed bee counts and vacuum‐sampled bee communities, weekly, when plots were in peak bloom. Across three field seasons, we found that Douglas' aster (Symphyotrichum subspicatum), California poppy (Eschscholzia californica), varileaf phacelia (Phacelia heterophylla), Canada goldenrod (Solidago canadensis), farewell‐to‐spring (Clarkia amoena), globe gilia (Gilia capitata), and Oregon sunshine (Eriophyllum lanatum) consistently harbored high bee abundance and species richness, and show great potential for garden pollinator plantings. These findings can be applied to residential and community gardens, municipal parks and other plantings, as well as by restoration professionals and policy makers interested in creating and supporting pollinator habitat. Across three field seasons, we compared the relative attractiveness of 23 native Pacific Northwest plant species to bees including 4 non‐native garden comparator plants. Several native plants were consistently more attractive to bees than the exotic comparator species. The bee communities associated with the study plants were significantly different, suggesting that informed plant community design in a garden setting could maximize a garden's ability to support bees.
... Although five species of bumblebees are reared commercially on a large scale, the Eurasian B.terrestris L. is the most reared subspecies for commercial pollination and has been used outside its natural distribution area. Very early after commercial introduction, it was recognized that this species is invasive and may disturb local ecosystems (Goulson, 2003). There are many invasive characteristics of B. terrestris such as high migration ability, early seasonal emergence, high adaptability under adverse climatic conditions in various habitat, polylectic foraging strategies and regulation of life cycle in a year in newly colonized area (Dafni et al., 2010). ...
Insufficient pollination due to low temperatures, high humidity, low light intensity and isolated atmosphere is one of the major problems in greenhouse vegetable production. These unsuitable conditions cause to insufficient production of fertile pollen, low pollen dynamism and finally serious pollination problems in greenhouses. Before 1990s, plant growth regulators which are also called as hormone spray were frequently used for greenhouse crop pollination. However, there is a worldwide interest to use the bumblebees as a pollinator of many crops in recent years. Due to their excellent pollinator behavior, bumblebees are indispensable element for especially greenhouse tomato production. Using of bumblebee also contribute to necessity of Good Agricultural Practices such as environmental sustainability, economic viability, social acceptability and food safety and quality. In this experiment, we aimed to evaluate the importance of commercially produced bumblebees in terms of environment friendly agriculture.
... In contrast, there is still no clear evidence regarding how resource availability affects honeybee abundance in urban ecosystems. It has been assumed that the densities of honeybees in urban ecosystems are more influenced by the distribution of the apiaries than by resource availability (Hennig & Ghazoul, 2011), due to honeybee foraging and movement traits (Goulson, 2003). In addition, most urban ecology studies do not include honeybees in their analyses (e.g., Braaker et al., 2014Braaker et al., , 2017Fortel et al., 2014) and the few that have included them found no effect of resource availability at any spatial scale (e.g., Wilson & Jamieson, 2019). ...
Cities are socio‐ecological systems that filter and select species, thus establishing unique species assemblages and biotic interactions. Urban ecosystems can host richer wild bee communities than highly intensified agricultural areas, specifically in resource‐rich urban green spaces such as allotment and family gardens. At the same time, urban beekeeping has boomed in many European cities, raising concerns that the fast addition of a large number of managed bees could deplete the existing floral resources, triggering competition between wild bees and honeybees. Here, we studied the interplay between resource availability and the number of honeybees at local and landscape scales and how this relationship influences wild bee diversity. We collected wild bees and honeybees in a pollination experiment using four standardized plant species with distinct floral morphologies. We performed the experiment in 23 urban gardens in the city of Zurich (Switzerland), distributed along gradients of urban and local management intensity, and measured functional traits related to resource use. At each site, we quantified the feeding niche partitioning (calculated as the average distance in the multidimensional trait space) between the wild bee community and the honeybee population. By using multilevel Structural Equation Models (SEM), we tested direct and indirect effects of resource availability, urban beekeeping and wild bees on the community niche partitioning. We found an increase in feeding niche partitioning with increasing wild bee species richness. Moreover, feeding niche partitioning tended to increase in experimental sites with lower resource availability at the landscape scale, which had lower abundances of honeybees. However, beekeeping intensity at the local and landscape scale did not directly influence community niche partitioning or wild bee species richness. In addition, wild bee species richness was positively influenced by local resource availability, while local honeybee abundance was positively affected by landscape resource availability. Overall, these results suggest that direct competition for resources was not a main driver of the wild bee community. Due to the key role of resource availability in maintaining a diverse bee community, our study encourages cities to monitor floral resources to better manage urban beekeeping and help support urban pollinators.
... This requirement to increasing foraging time, coupled with the narrower foraging windows imposed by increasing temperatures, is likely to have a compounding negative impact on bee populations (Corbet et al. 1993;Maia-Silva et al. 2020;Souza-Junior et al. 2020). Apis mellifera may also increasingly outcompete native bees for floral resources under climate change scenarios, given their broader activity temperatures (Goulson 2003). Conversely, bees like E. robusta with greater heat tolerance might do well under warming conditions, but additional data are required to understand this response. ...
The response of bees to changing environmental temperatures has implications for pollination in natural and agricultural systems, with rising average temperatures and increased environmental stochasticity predicted to cause pollinator population declines. A growing body of evidence for the role of native bees in crop pollination suggests that understanding the temperatures at which bees are active is important for maintaining agricultural productivity under climate change. This study used two methods to sample bees at strawberry farms in south‐eastern Australia, matching activity observations with microclimate temperature to understand how temperature impacts bee activity. Apart from Apis mellifera (introduced), two native bees were identified, Lasioglossum spp. and Exoneura robusta. Apis mellifera was the most abundant species across all environmental temperatures, and E. robusta the least. Visual and sweep‐netting survey results found activity temperature range was broader for A. mellifera (16.21–41.05°C) than Lasioglossum (16.49–38.91°C) and E. robusta (26–38.82°C). The results suggest that activity temperature varies among bee species, with potential implications for community composition and plant pollination under climate change.
... Some studies suggest that the introduction of honey bees (Apis spp.) may also have negative impacts, such as competition with the native pollinators for available floral resources, competition for nesting sites, co-introduction of nesting enemies, especially pathogens that infect the native organisms, disruption of pollination services of native plants and pollinating exotic weeds. Thus the ecological impacts of cavity occupancy by introduced honey bees (Apis spp.) gone feral is a subject that needs a complete review by itself (Goulson, 2003;Saunders et al., 2021). ...
Ecosystems are rapidly urbanizing at the global and regional scales, particularly in the tropics, which has deleterious effect on hymenopteran pollinators. Based on the literature spanning multiple disciplines including ecology, pollination, agriculture, agroecology and entomology, this review deliberates on the pollinators and their global decline. Also, it turns the focus on honey bees and their role in agroecosystem. Relevant information from melissopalynology is brought together and the gaps and directions of future research on conservation and management of honey bees in tropical peninsular India are discussed. Focus is on the two species of the hived native Apis cerana indica F., and Tetragonula iridipennis Smith (Hymenoptera: Apidae), as these play a major role in transforming existing agricultural landscapes into agroecosystems, benefitting the farmers and maintaining ecological balance in tropical peninsular India. This review brings to the fore the fact that there is a tangible gap in reports and long-term studies of many native pollinators and in particular the two hived honey bees. Most studies present in a thorough manner visual observations of pollinators (bees) on plants but rarely combine them with quantifying the resources gathered from the plants, especially pollen. This combined approach is especially important to understand the hymenopteran pollinators from the purview of the pollination service they provide. It can be concluded that there is a pressing requirement for long-term observations along these lines with quantifiable pollen and vegetation data to arrive at meaningful plant-pollinator networks that are essential for conservation and management of the native Asiatic honey bees as pollinators.
... Honeybees remain a popular and charismatic species for "save the bees" campaigns, and millions of farmers rely on their pollination services. However, there are very few studies assessing the role that introduced bees may play in limiting populations of native species (Fitch, Wilson, et al., 2019;Forup & Memmott, 2005;Henry & Rodet, 2018), and of those published, there are mixed results (Goulson, 2003;Paini & Roberts, 2005), even fewer have addressed this issue in urban landscapes, where highly patchy resources create higher pressure for resources, and likely greater rates of competition. In this review we highlight two papers that directly assess competitive behaviors between introduced species and native bee species. ...
Numerous animal species can survive in human-modified habitats, but often display behavioral, morphological, physiological or genetic plasticity compared to non-urban conspecifics. One group of organisms with a large urban presence are bees. Bee species have high diversity and abundance in cities, which has been empirically supported in numerous studies assessing community composition. Recent reviews of these articles reveal global patterns of high bee richness in cities, and the impact of urban landscape characteristics on bee populations. However, more specific information about how bees are able to be successful in cities, as have been studied in birds and mammals, has not been prioritized in any review thus far. These topics, though uncommon in much of the current published literature, are important for understanding how urban pollinating bees survive. Therefore, the goal of this paper is to review urban bee literature, focusing on topics that have yet to be examined in entirety, but are crucial for the plasticity observed, including foraging, nesting, competition, physiological adaptations, morphological shifts, genetics and gene flow. Additionally, we provide predictions and propose possible experimental directions based upon what is currently known about urban animal populations and bee life history. These predictions aim to inspire future multidisciplinary research to holistically evaluate urban bee populations. Expanding the knowledge base from primarily community composition studies to intricate assessments of behavior, genetics, and other important traits will aid in the creation of more targeted conservation policies, land development, and improve the capacity for pollination services in cities.
... It also applies both where honeybees are native (e.g., Brown et al., 2009) and where they are introduced (e.g., Celebrezze and Paton, 2004). The introduction of honeybees to continents and islands where they are not native has raised concerns about their effects on native pollinators and local flora (Goulson, 2003). The potential negative repercussions of honeybees on native plant fecundity include pollen theft, both from anthers and stigmas, and ovule and seed discounting (this study, Gross and Mackay, 1998;England et al., 2001), as well as disruption of other plant-pollinator interactions (e.g., Valido et al., 2019). ...
Premise:
Honeybees dominate the flower-visitor assemblages of many plant species, yet their efficiency in terms of the quality of pollen delivered to stigmas is largely unknown. We investigated why honeybees are poor pollinators of Aloe ferox, a self-incompatible succulent treelet with large numbers of flowers. Honeybees are very frequent visitors to flowers of this species, yet contribute very little to seed production.
Methods:
We assessed pollen loads on honeybees, studied their visitation behavior, selectively excluded birds from plants to determine direct effects of bees on pollen deposition, seed set, and ovule abortion, and used a novel "split-pollinator" method to test whether honeybees deposit mainly low-quality self pollen. For the latter, we captured honeybees, and with their existing pollen loads, used them to either pollinate virgin flowers on the plant on which they were caught or to pollinate virgin flowers on different plants.
Results:
Honeybees cumulatively deposit as much pollen on stigmas as do birds, but our experiments showed that the pollen deposited by honeybees is mostly low-quality self pollen that leads to substantial ovule discounting and depressed seed set.
Conclusions:
Lack of movement among A. ferox plants during individual honeybee foraging bouts is the most likely explanation for their deposition of low-quality self pollen on stigmas. The "split-pollinator" method is a simple and cost-effective technique to test the quality of pollination.
... Therefore, for the maintenance and conservation of native bee species in human-modified landscapes, it is essential to provide suitable nesting sites and materials for nest building, as well as constant food sources, for example nectar and pollen throughout the year Golubov et al. 2010;Hudewenz & Klein 2013;DiCarlo et al. 2019). Nevertheless, although shelter and food supplies can be guaranteed throughout the year in natural ecosystems, native bees may not necessarily succeed in modified landscapes when dominant bee species, such as the exotic honeybee, Apis mellifera C. Linnaeus, 1759 are present, primarily because native species can be very sensitive and outcompeted by honeybees (Goulson 2003;Magrach et al. 2017;Hachuy-Filho et al. 2020). This is especially problematic in fragmented ecosystems, such as the Brazilian Cerrado, where A. mellifera was introduced in the mid-twentieth century (Kerr 1957). ...
Nectar is the most common floral resource that mediates plant–pollinator interactions, and its spatiotemporal distribution is related to pollinator attraction and can influence pollinator activity through time. Therefore, assessing patterns of floral phenology of nectar‐producing plants can help better understand the pollinator assemblage's temporal dynamics. We used an area of afforested Brazilian Cerrado covered with a high‐density plantation of Inga vera, a mass‐flowering nectar‐producing tree, to investigate whether intra‐seasonal and daily variations in nectar availability provided by I. vera flowers affect the bee assemblage. We showed that bee abundance was positively related to intra‐seasonal patterns in floral phenology and daily changes in nectar production. Although bee species richness was also associated with intra‐seasonal changes in nectar availability, bee diversity (quantified using Simpson's diversity index) did not follow the same pattern. We suggest that the dominance of the invasive honeybee, Apis mellifera, on I. vera flowers may have affected the overall bee diversity over time due to an exacerbated increase in honeybee abundance. Therefore, by evaluating the temporal dynamics of nectar availability, an important floral attribute that influences plant–pollinator interactions, we suggest that planting high‐rewarding tree species at high densities in open ecosystems can affect the dynamics of native bee assemblages negatively due to the exacerbated recruitment of the dominant exotic honeybee.
... In this study, we analyzed 95 plant-floral visitor networks encompassing ca. 87 degrees of latitude and 227 degrees of longitude across the globe, and found that A. mellifera has a higher interactive role within plant-floral visitor networks in sites where it is exotic compared to those within its native range, which indicates a high capacity to tolerate environments outside its native range perhaps via phenotypic plasticity and to exploit efficiently the available resources in those sites (Goulson, 2003;Manfredini et al. 2019). At a global scale, we found that temperature and precipitation, individually, and latitude in conjunction with human influence have a direct influence on the interactive role of A. mellifera within plant-floral visitor networks. ...
Empirical evidence has shown that introduced honeybees, Apis mellifera L., can change the structural organization of ecological networks involving pollinators and flowering plants. In this case, studies have shown that A. mellifera is highly connected within networks (i.e., high interactive role) mainly due to its high abundances, long colony lifetime, generalist diet, and great capacity of spread and adaptation to new environments. However, there is little knowledge on how the interactive role of A. mellifera in these flower-visitor networks changes spatially and the potential correlates of such variation across ecological and geographical gradients worldwide. In this study, we evaluated how native and exotic distribution ranges, local climate, human influence (i.e., anthropogenic disturbance), and latitude shape the interactive role of the honeybee in plant-floral visitor networks globally. To achieve that, we compiled 95 weighted plant-floral visitor networks encompassing ca. 87 degrees of latitude and 227 degrees of longitude across the globe. We found that the interactive role of A. mellifera is higher in its exotic range than in the native distributional range and positively associated with mean annual temperature and precipitation. Further, the interactive role of A. mellifera was high at intermediate values of global human influence and increased with latitude. Our findings help us to understand how different drivers related to rapid global change could affect the capacity of A. mellifera to colonize and increase its impact on other pollinator species in different environments.
The Neotropical orchid bee Euglossa dilemma was found to be naturalized in southern Florida in 2003, and, by 2022, it had colonized the southern half of Florida. Observations of the bee’s collection of plant resources, primarily flowers, were made from 2003 through to 2022 to document its plant usage and understand the patterns of its plant usage. The bee utilized 259 plant taxa, 237 species, and 22 horticultural forms, in 156 genera and 56 families in 263 total uses. Of 247 taxa of flowers, 120 were visited primarily for nectar, 46 for both nectar and pollen, 60 for pollen, including 42 buzz-pollinated flowers, 15 for fragrance chemicals for the males, and 5 for resin rewards by females for nesting. Fragrance chemicals were also collected by males from the leaves of 12 plant species. These extensive resource use data allowed the following predictions to be made. (1) The bee’s presence in Florida, distant from its native region of Mexico and Central America and the geographical ranges of other orchid bees, would result the usage of many new taxa of plants. True, half, 74/148 (50%), of the genera and one third, 16/51(31%), of the plant families of the plants with flowers used by the bee were not previously recorded as being utilized by Euglossine bees. (2) Like other naturalized bees, it would use relatively more plants from its native range or congeners of these plants. True, 113/148 (76%) of genera with species bearing collected floral rewards are native or congeners with species native to the bee’s native range. (3) Given the bee’s long tongue, ability to buzz pollen from poricidal anthers, and ability to collect and use specialized rewards, it would disproportionately use plants with protected or highly specialized floral rewards. True, 180/247 (72%) utilized species bear rewards which were protected and unavailable to, or of no interest to, most other flower visitors.
Invasive insects pose a significant threat to native plant species and ecosystems, particularly in the context of changing climates. Understanding these interactions is crucial for effective conservation and management strategies aimed at mitigating the adverse effects of invasive species on native plant communities. Invasive insects often establish and proliferate in new habitats due to the absence of natural enemies and the availability of suitable resources. As climate change alters the distribution and phenology of plants, it can influence the susceptibility and resilience of native plant species to invasive insects. In some cases, rising temperatures and altered precipitation patterns may favour the spread and population growth of invasive insects, leading to increased herbivory, reduced plant fitness, and ultimately, altered community dynamics. Furthermore, changing climates can disrupt the synchrony between native plants and their pollinators or beneficial insect populations, further exacerbating the impacts of invasive insects. As native plants and pollinators respond differently to shifting climatic conditions, their interactions may become disrupted, potentially reducing the reproductive success and long-term survival of native plant populations. However, it is important to note that climate change can also create novel opportunities for both invasive insects and native plant species. In certain instances, invasive insects may benefit from warmer temperatures and expanded ranges, while some native plants may exhibit adaptive responses and resilience to changing climatic conditions. These complex interactions highlight the need for a comprehensive understanding of the ecological dynamics between invasive insects and native plant species under various climate scenarios. The ecological interactions between invasive insects and native plant species in changing climates have far-reaching consequences for biodiversity conservation and ecosystem functioning. As climates continue to evolve, it is imperative to further investigate these interactions and develop adaptive strategies to mitigate the impacts of invasive insects on native plant communities. By doing so, we can strive to preserve and restore ecological balance in the face of ongoing environmental change.
Native pollinators are crucial to local ecosystems but are under threat with the introduction of managed pollinators, e.g., honeybees (Apis mellifera). We explored the feasibility of employing the entomological lidar technique in native pollinator abundance studies. This study included individuals of both genders of three common solitary bee species, Osmia californica, Osmia lignaria, and Osmia ribifloris, native to North America. Properties including optical cross-section, degree of linear polarization, and wingbeat power spectra at all three wavelengths have been extracted from the insect signals collected by a compact stand-off sensing system. These properties are then used in the classification analysis. For species with temporal and spatial overlapping, the highest accuracies of our method exceed 96% (O. ribifloris & O. lignaria) and 93% (O. lignaria & O. californica). The benefit of employing the seasonal activity and foraging preference information in enhancing identification accuracy has been emphasized.
Invasive insects pose a significant threat to native plant species and ecosystems, particularly in the context of changing climates. Understanding these interactions is crucial for effective conservation and management strategies aimed at mitigating the adverse effects of invasive species on native plant communities. Invasive insects often establish and proliferate in new habitats due to the absence of natural enemies and the availability of suitable resources. As climate change alters the distribution and phenology of plants, it can influence the susceptibility and resilience of native plant species to invasive insects. In some cases, rising temperatures and altered precipitation patterns may favour the spread and population growth of invasive insects, leading to increased herbivory, reduced plant fitness, and ultimately, altered community dynamics. Furthermore, changing climates can disrupt the synchrony between native plants and their pollinators or beneficial insect populations, further exacerbating the impacts of invasive insects. As native plants and pollinators respond differently to shifting climatic conditions, their interactions may become disrupted, potentially reducing the reproductive success and long-term survival of native plant populations. However, it is important to note that climate change can also create novel opportunities for both invasive insects and native plant species. In certain instances, invasive insects may benefit from warmer temperatures and expanded ranges, while some native plants may exhibit adaptive responses and resilience to changing climatic conditions. These complex interactions highlight the need for a comprehensive understanding of the ecological dynamics between invasive insects and native plant species under various climate scenarios. The ecological interactions between invasive insects and native plant species in changing climates have far-reaching consequences for biodiversity conservation and ecosystem functioning. As climates continue to evolve, it is imperative to further investigate these interactions and develop adaptive strategies to mitigate the impacts of invasive insects on native plant communities. By doing so, we can strive to preserve and restore ecological balance in the face of ongoing environmental change.
Insect pollinators, such as bees, butterflies, and flies, play a critical role in plant reproduction and the functioning of ecosystems. Their diversity is vital for efficient pollination, genetic variability in plants, and maintaining ecosystem resilience. However, these pollinators are under threat due to habitat loss, climate change, and pesticide use, resulting in population declines. To safeguard pollinators, it is imperative to take actions like creating pollinator-friendly gardens, avoiding pesticides, and promoting sustainable agriculture practices. The diversity of insect pollinators contributes to ecosystem resilience by preserving plant diversity and productivity. It also plays a significant role in global food security by enhancing crop yield, quality, and diversity. Challenges faced in pollinator-dependent agriculture include habitat loss, pesticide use, climate change, invasive species, and diseases. The decline in pollinator diversity has far-reaching consequences, including reduced crop yields and compromised ecosystem resilience. Conservation strategies focus on preserving diverse habitats, implementing agroecological practices, and raising public awareness about the importance of pollinators. Protecting and enhancing insect pollinator diversity is crucial for the overall health of ecosystems, agricultural systems, and the well-being of humans and the planet. Introduction Insect pollinators, including bees, butterflies, flies, beetles, and moths, play a fundamental role in plant reproduction and the functioning of ecosystems. The diversity of insect pollinators is essential for maintaining ecosystem resilience, promoting genetic diversity in plants, and ensuring global food security. Each type of pollinator has its own unique way of transferring pollen. For example, bees use their fuzzy bodies to collect pollen, while butterflies use their long tongues to reach into the depths of flowers. Insect pollinators are essential for the health of ecosystems and agriculture. Without them, many plants would not be able to reproduce, and we would have a much smaller variety of fruits, vegetables, and seeds to eat. However, insect pollinators are facing a number of threats, including habitat loss, climate change, and pesticide use. These threats are causing the populations of many insect pollinators to decline. It is important to take steps to protect insect pollinators. We can do this by planting pollinator-friendly gardens, avoiding the use of pesticides, and supporting sustainable agriculture practices. This article explores the significance of insect pollinator diversity, its drivers, and the potential consequences of its decline.
Los pesticidas utilizados en la agricultura, las áreas urbanas y los jardines están generando preocupaciones sobre su impacto en los polinizadores. La exposición a pesticidas por contacto directo, ingestión y acumulación puede dañar a los polinizadores. Las altas concentraciones causan daños inmediatos, mientras que la exposición crónica debilita sus sistemas inmunológicos, perjudica la reproducción y conduce a la disminución de la población. Los neonicotinoides, un tipo de insecticida, son especialmente problemáticos. Son absorbidos por las plantas y se propagan al néctar y al polen, lo que afecta la capacidad de búsqueda de alimento, la navegación, la inmunidad y el éxito reproductivo de los polinizadores. Pesticidas Se están realizando esfuerzos para proteger a los polinizadores a través de estrategias alternativas de manejo de plagas. El manejo integrado de plagas y polinizadores (IPPM), las prácticas de agricultura sostenible y las zonas libres de pesticidas tienen como objetivo mantener el equilibrio ecológico y reducir el uso de productos químicos. Crear conciencia sobre la importancia de los polinizadores y los impactos de los pesticidas es crucial para la conservación, y al equilibrar el control de plagas con la protección de los polinizadores, se puede garantizar la sostenibilidad a largo plazo de la agricultura y los ecosistemas naturales que dependen de los servicios de polinización. Introducción La toxicidad de los pesticidas para los insectos polinizadores es una preocupación importante debido al papel vital que desempeñan estos insectos en la polinización de las plantas con flores, incluidos muchos cultivos importantes. Si bien los pesticidas son herramientas esenciales para controlar las plagas y garantizar la producción de alimentos, sus posibles efectos adversos sobre los polinizadores requieren una cuidadosa consideración para proteger estas valiosas especies. Comprender la toxicidad de los pesticidas para los polinizadores implica examinar los tipos de pesticidas, sus modos de acción y los impactos que pueden tener en la salud y las poblaciones de los polinizadores. Los plaguicidas pueden tener efectos perjudiciales sobre los insectos polinizadores, incluidas las abejas, las mariposas y otros insectos beneficiosos que intervienen en el proceso de polinización. Si bien los pesticidas son esenciales para controlar las plagas y garantizar la productividad de los cultivos, su uso requiere una consideración cuidadosa para minimizar el daño a los polinizadores, que desempeñan un papel crucial en la salud del ecosistema y la producción de alimentos.
Pesticides used in agriculture, urban areas, and gardens are raising concerns about their impact on pollinators. Exposure to pesticides through direct contact, ingestion, and accumulation can harm pollinators. High pesticide concentrations cause immediate harm, while chronic exposure weakens their immune systems, impairs reproduction, and leads to population declines. Neonicotinoids, a type of insecticide, are especially problematic. They are absorbed by plants and spread to nectar and pollen, affecting foraging abilities, navigation, immunity, and reproductive success in pollinators. Efforts are underway to protect pollinators through alternative pest management strategies. Integrated pest and pollinator management (IPPM), sustainable agriculture practices, and pesticide-free zones aim to maintain ecological balance and reduce chemical use. Raising awareness about pollinator importance and pesticide impacts is crucial for conservation, and by balancing pest control with pollinator protection, long-term sustainability of agriculture and natural ecosystems dependent on pollination services can be ensured. Introduction The widespread use of pesticides has emerged as a major concern for pollinator populations. Insecticides, herbicides, and fungicides are commonly used in agricultural practices, urban settings, and even home gardens to control pests and weeds. However, the unintended consequences of pesticide use on pollinators have become increasingly apparent. Exposure to pesticides can occur through various routes, including direct contact with sprayed surfaces, ingestion of contaminated pollen and nectar, and the accumulation of pesticide residues in soil and water sources. These chemicals can have detrimental effects on pollinators, both in the short term and over extended periods.Acute toxicity can occur when pollinators are exposed to high concentrations of pesticides, leading to immediate adverse effects such as disorientation, paralysis, and even death. For example, certain insecticides target the nervous systems of insects, disrupting their ability to navigate, forage, and communicate effectively. This can result in pollinators being unable to find food sources or return to their hives or nests, ultimately impacting their survival. Furthermore, chronic exposure to sublethal doses of pesticides can have subtle but significant impacts on pollinators. Prolonged exposure weakens their immune systems, making them more susceptible to diseases and parasites. It can also impair their reproductive capabilities, including reduced fertility, altered mating behaviors, and decreased brood production. Over time, these effects can lead to population declines and ecological imbalances.
Due to declines in pollinator populations, many people are now interested in learning about which annual flowers they can plant in their garden to better support pollinators. However, reports of experimental evaluation of cultivars of annual flowers for attraction to pollinators are scarce. We sampled pollinators visiting six cultivars of marigold (Tagetes erecta and T. patula), ten cultivars of bidens (Bidens ferulifolia and B. aurea), and eight cultivars of portulaca (Portulaca oleracea and P. grandiflora) for two years to compare pollinator visitation rates among cultivars within each flower type. Pollinators collected on flowers in research plots were categorized into four groups, honey bees (Apis mellifera), common eastern bumble bees (Bombus impatiens), wild bees, and syrphids, to show the proportion of different pollinator visitors to each cultivar. Pollinator visitation rates varied significantly among cultivars of marigold, bidens, and portulaca, with some cultivars having as much as 10-fold the visitation rate of other cultivars of the same flower type. In the second year we also evaluated nectar production and nectar quality of the most and least visited cultivars of portulaca and bidens. Our results show that pollinators have a strong preference for cultivars that produce the most nectar or nectar with the highest sugar content. This research will better inform entomologists, growers, educators, and plant breeders, about which cultivars of marigold, portulaca, and bidens are visited the most by pollinators, and how to accurately determine this at the cultivar level.
Bees are important pollinators and are essential for the reproduction of many plants in natural and agricultural ecosystems. However, bees can have adverse ecological effects when introduced to areas outside of their native geographic ranges. Dozens of non-native bee species are currently found in North America and have raised concerns about their potential role in the decline of native bee populations. Osmia taurus Smith (Hymenoptera: Megachilidae) is a mason bee native to eastern Asia that was first reported in the United States in 2002. Since then, this species has rapidly expanded throughout the eastern part of North America. Here, we present a comprehensive review of the natural history of O. taurus, document its recent history of spread through the United States and Canada, and discuss the evidence suggesting its potential for invasiveness. In addition, we compare the biology and history of colonization of O. taurus to O. cornifrons (Radoszkowski), another non-native mason bee species now widespread in North America. We highlight gaps of knowledge and future research directions to better characterize the role of O. taurus in the decline of native Osmia spp. Panzer and the facilitation of in-vasive plant-pollinator mutualisms.
Socio-environmental issues become evident in countries with megadiversity. Brazil finds itself in this context, adding to the fact that it has severe socioeconomic inequalities, of which we highlight the lack of environmental justice. The present study has education for citizenship and biodiversity as its principles, considering that this interface empowers the students to emerge from socio-political perspectives to overcome environmental injustices. The objective is, therefore, to identify concepts of biodiversity and citizenship present in arguments developed by high school students in a socioscientific discussion. The research participants were nine students from a rural and public school in Brazil. We designed and implemented a Focus Group on the disappearance of bees and its consequences. The participants’ speeches were structured in arguments and analyzed from categories regarding the dimensions of citizenship and biodiversity. We identified the relationship among all categories in the arguments listed. However, we observed that these students are not full citizens since they identify several obstacles to active participation in social transformation actions. This study aims to contribute to research and science education strategies to promote active citizenship and critical perspectives on biodiversity.
Understanding the structural diversity of honeybee-infecting viruses is critical to maintain pollinator health and manage the spread of diseases in ecology and agriculture. We determine cryo-EM structures of T = 4 and T = 3 capsids of virus-like particles (VLPs) of Lake Sinai virus (LSV) 2 and delta-N48 LSV1, belonging to tetraviruses, at resolutions of 2.3–2.6 Å in various pH environments. Structural analysis shows that the LSV2 capsid protein (CP) structural features, particularly the protruding domain and C-arm, differ from those of other tetraviruses. The anchor loop on the central β-barrel domain interacts with the neighboring subunit to stabilize homo-trimeric capsomeres during assembly. Delta-N48 LSV1 CP interacts with ssRNA via the rigid helix α1’, α1’–α1 loop, β-barrel domain, and C-arm. Cryo-EM reconstructions, combined with X-ray crystallographic and small-angle scattering analyses, indicate that pH affects capsid conformations by regulating reversible dynamic particle motions and sizes of LSV2 VLPs. C-arms exist in all LSV2 and delta-N48 LSV1 VLPs across varied pH conditions, indicating that autoproteolysis cleavage is not required for LSV maturation. The observed linear domino-scaffold structures of various lengths, made up of trapezoid-shape capsomeres, provide a basis for icosahedral T = 4 and T = 3 architecture assemblies. These findings advance understanding of honeybee-infecting viruses that can cause Colony Collapse Disorder.
Biological diversity of bee - the genetic resource in Russia, which enables maintaining homeostasis of ecosystems through pollination entomophilies plants. The biodiversity of bees in human life has ecological, social, economic and aesthetic significance. Of particular interest in the preservation of biodiversity are taxonomically isolated species and populations, not resemble others and therefore unique in their genetic constitution. These species are often endemic, that is limited to the dissemination of one area. Their extinction of will mean the loss of biodiversity. Uncontrolled introduction of bees of different species breeds and populations leads to the spread of diseases and hidden genetic defects. In the process of mass introduction of not adapted breeds of honey bees there is a loss of breed diversity of endemic populations, accompanied by a narrowing of breeding opportunities and a reduction in pollinators. Using modern methods of monitoring with the use of microsatellite analysis to improve the efficiency study of the gene pool of honeybees. Biotechnological methods of artificial insemination of Queens and cryopreservation of drone sperm in liquid nitrogen allow preserving the gene pool of endangered native breeds of honeybees. The use of these methods makes it possible to avoid polyandry and conduct controlled mating in breeding and genetic studies. Obtaining a culture of honeybee cells is promising for a more in-depth study of the interaction with intracellular infectious agents, genomic and epigenetic mechanisms of variability of this unique object.
Introduced species often benefit from escaping their enemies when they are transported to a new range, an idea commonly expressed as the enemy release hypothesis. However, species might shed mutualists as well as enemies when they colonize a new range. Loss of mutualists might reduce the success of introduced populations, or even cause failure to establish. We provide the first quantitative synthesis testing this natural but often overlooked parallel of the enemy release hypothesis, which is known as the missed mutualist hypothesis. Meta-analysis showed that plants interact with 1.9 times more mutualist species, and have 2.3 times more interactions with mutualists per unit time in their native range than in their introduced range. Species may mitigate the negative effects of missed mutualists. For instance, selection arising from missed mutualists could cause introduced species to evolve either to facilitate interactions with a new suite of species or to exist without mutualisms. Just as enemy release can allow introduced populations to redirect energy from defence to growth, potentially evolving increased competitive ability, species that shift to strategies without mutualists may be able to reallocate energy from mutualism toward increased competitive ability or seed production. The missed mutualist hypothesis advances understanding of the selective forces and filters that act on plant species in the early stages of introduction and establishment and thus could inform the management of introduced species.
There is an ongoing debate if and to what extend honey bees (Apis mellifera) might present competition against other pollinators, particularly other species of bees. In our comment we reanalyze data from Weekers et al. (2022) on bee pollinators of apple, collected in an impressive large-scale study in Western Europe. We challenge one of their findings related to competition as we disagree with correlating [bee] species richness (# species in a sample) and honey bee dominance (the percentage of honey bees in the same sample). We show that according to this way of data transformation even computed datasets without any correlations inevitably result in a negative relationship. As honey bee dominance increases towards 100%, the species richness will approach one. Only one species will be present, that is the honey bee, because the values for wild bee and honey bee values are not independent. This explains why they report a negative relationship, though we found no correlation reanalysing their raw data. We hope this comment facilitates our understanding of this important topic and advances future research, as well as supports informed decisions for policy makers.
Plant species that are alien and invasive represent an important threat to biodiversity and ecosystem function. These plants compete with native flora for resources and pollinator services. Although most invasive plant species do not depend on pollinators for reproduction and can reproduce uniparentally, some depend on pollinator-assisted reproduction and therefore rely on recruitment of pollinators in the new habitat. Here, we studied Solanum rostratum, a high-risk invasive weed widely distributed around the world that depends on buzz-pollination. It has a floral morphology that depends on medium and large-sized buzzing bees for pollination. The main aim of this study is to model the distribution of an invasive plant, Solanum rostratum, using ecological niches based on its buzz-pollinator distribution. Thus, we hypothesized that S. rostratum is more likely to establish successfully in geographic regions where the appropriate buzz pollinators are also found. We considered the realized and potential distribution of S. rostratum and its pollinators based on occurrence data and ecological niche models combining both abiotic (climatic conditions) and biotic (potential pollinator distribution) factors using the MaxEnt algorithm. Five climatic variables related to temperature and precipitation were important in determining the realized distribution of S. rostratum, while seasonal temperature was the most important variable in determining pollinator distribution. The distributions of the bumblebees (Bombus fraternus, B. griseocollis, and B. impatiens) were closely related to the realized distribution of S. rostratum. However, the potential distribution of S. rostratum is wider than that of the pollinator included here, suggesting that other factors such as modifications in the reproductive system or recruitment of other buzzing and non-buzzing bees might be occurring in some invasive populations. We also found that S. rostratum has the potential to expand to unoccupied regions in South America, South Africa, Eastern Europe, and the Middle East. In conclusion, modeling of niches used by invasive species considering both climatic variables and biological interactions such as pollination would be very useful to study and predict the distribution of invasive plants which depend on pollinators to reproduce and establish in new habitats.
The decline of pollinators is a widespread problem in today's agriculture, affecting the yield of many crops. Improved pollination management is therefore essential, and honey bee colonies are often used to improve pollination levels. In this work, we applied a spatially explicit agent-based model for the simulation of crop pollination by honey bees under different management scenarios and landscape configurations. The model includes 1) a representation of honey bee social dynamics; 2) an explicit representation of resource dynamics; 3) a probabilistic approach to the foraging site search process; and 4) a mechanism of competition for limited resources. We selected 60 sample units from the rural landscape of the Chilean region with the largest apple-growing area and evaluated the effectiveness of different pollination strategies in terms of number of visits and number of pollinated flowers per hectare of apple crops. Finally, we analyzed how the effects of these practices depended on the structure of adjacent landscapes. Higher colony density per hectare in the focal crop increased the number of honey bee visits to apple inflorescences; however, the effects were nonlinear for rates of pollinated flowers, suggesting that there is an optimum beyond which a greater number of honey bees does not signify increased levels of crop pollination. Furthermore, high relative proportions of mass flowering crops and natural habitats in the landscape led to a decrease in honey bee densities in apple fields in landscapes with high relative cover of apple orchards (dilution effect). Our results indicate that for optimal crop pollination, strategies for management of pollinator species should consider the modulating effects of the surrounding landscape on pollination effectiveness. This model could thus be a useful tool to help farmers, beekeepers, and policy-makers plan the provision of pollination services, while also promoting the biodiversity and sustainability of agroecosystems.
Surveys of nesting sites of feral honey bees {Apis mellifera) and regent parrots {Polytelis anthopeplus) were made in the red gutn/black box woodlands of Wyperfeld National Park, Victoria, Australia. Data on tree species and size, and number of hollows were collected from all trees within seven 500 x 100 m plots. Nest site characteristics were quantified for both bees and parrots. We found 27 feral honey bee colonies, suggesting a density of 77.1 colonies per km^. The average occupation rate for bees was 1.3% of trees and 0.7% of available hollows. The height, aspect and entrance characteristics of honey bee nests at Wyperfeld were not qualitatively different to those reported elsewhere. We found 15 pairs of nesting regent parrots. Nest sites chosen by these birds overlapped those chosen by honey bees, but 52% of bee nests were in cavities unsuitable for regent parrots. We suggest that honey bee population growth may be limited in the park by a lack of water.
Contrary to traditional thinking, Bombus jonellus (Kirby) is not the only bumble bee in Iceland. An ecological study of the species in 1979 revealed the presence of B. hortorum (L.), B. lucorum (L.) and B. jonellus.
B. hortorum was found in the Rekjavik area in habitats supporting introduced flowers, and was unrepresented prior to 1959 in collections dating back to 1913. B. hortorum has probably become established since the 1950's, and B. lucorum may also be a recent introduction.
Purple loosestrife is a serious weed of wetlands in Canada, particularly in Ontario and Quebec. Lythrum is a heterostylous species and clones by means of root buds. Despite its tristylous breeding system, it is a successful colonizer, and can produce prodigious numbers of seeds. Control can be achieved by hand-pulling in low-density populations, but once the species is established it generally becomes abundant and often approaches a monoculture. This species is particularly difficult to control because of its strong competitive ability, the extreme sensitivity of wetland habitats, and the likelihood of serious repercussions for wetland wildlife and fisheries if herbicides are used to control it. Better possibilities for control exist through cultural techniques (eg manipulation of water levels to favour native species), enhancement of North American herbivores, and, possibly, the introduction of biological control agents from Europe and Asia. -from Authors
Ants of Formica neorufibarbus gelida are nectar thieves of Polemonium viscosum. Ants interfere with seed production by severing the base of the style or chewing through the ovary during nectar foraging, rather than by lowering reward levels available to pollinators. During the summers of 1979 and 1981 flowers of >25% of P. viscosum plants censused in the krummholz of the Colorado alpine were damaged by nectar thieving ants. The frequency of ant visitation decreased at higher altitudes. Individual P. viscosum have a predominant floral scent that is either sweet or skunky. Ants visited considerably more individuals with sweet flowers than expected from local morph abundance, and undervisited plants with skunky flowers.-from Author
Several diversity-related measures (richness, H′, hierarchical information, species abundance distributions) are used to examine the hypothesis that members of the bee guild of high-altitude, shortgrass prairie compete for limited floral resources. Data on bee and flower populations was collected for two years at two sites. We reasoned that competition should be reflected by: (1) similar species abundances distributions for bees and flowers; (2) strong positive correlations between the total flower abundance of a species and the number of bee visitors; (3) strong positive correlations between bees and flowers in diversity and abundance when samples were taken at frequent intervals. Results are generally inconsistent with the hypothesis that either bees continuously compete for floral resources or vice-versa. Instead, the data support the hypothesis that competition is intermittent due to (1) a spatiotemporally unpredictable resource base, (2) the fact that adult bees are the products of the previous years resource supply rather than that available in the year of emergence. /// Несколько величин, определяющих разнообразне (богатсво, Н́, иерархическая информация, распределение обилия внодов) использованы для проверки гипотезы о том, что пеелы в сообществе высотной низкотравной прерии конкурируют за лимитированные флорнстические ресурсы. Данные по характеристике популяций пчел и цветковых растений собраны в течение 2-х лет в 2-х местообитаниях. Мы предполагаем, что конкуренция зависнт от следующих факторов: 1. сходное распределение обилия определенных вндов у пчел и цветковых; 2. тесная положнтельная межцу общим обилием цветов у одного вида и числом посещений пчел. 3. тесная положительная корреляция величин, характеризующих разнообразие и обилие у пчел и цветов, при взятии проб через короткие интерваы. Пезультаты в целом не сообразуютчя с гнпотезой о наличии у пчел постоянной конкуренции за флорнстические ресурсы, либо ее отсутствии. Вместо этого данные поддерживают гипотезу о наличии прерывнстой конкуренции в пезультате: 1. пространственно-временной нелредсказуемой омене ресурсов и 2. того факта, что наличне взросных пчел отражает скорее величину ресурсов прощых лет, чем их доступность в род выпета имаго.
In experimental plots, E. asimillima showed: increased adult emigration, increased brood rearing success, and/or relatively later colony founding, compared to controls. The possibility of resource competition with Apis mellifera causing the observed changes is discussed. -Authors
1. Flower nectar robbers which extract flower rewards to pollinators but do not pollinate, may reduce the fitness of the plant. In this study we combined field observations and experimental manipulations to assess the role of a primary nectar robber, the bird Diglossa baritula, on flower nectar secretion and reproductive output of two hummingbird-pollinated plant species with contrasting breeding systems. We used the hermaphroditic Salvia mexicana and the androdioecious Fuchsia microphylla. In addition, because the distinction between pollinators and robbers is not so sharp, we compared the pollination efficiencies of D. baritula and of five species of humming-birds visiting the flowers of the same plant species. 2. Flowers of the two plant species were frequently robbed (92 and 37% of the flowers in Salvia mexicana and Fuchsia microphylla respectively). For both species, field censuses of robbed and unrobbed flowers showed no differences in fruit set. Experimentally induced nectar robbery did not affect the cumulative production of nectar in both plant species. However, in S. mexicana, but not in F. microphylla, intact flowers produced more concentrated nectar. 3. The role of D. baritula and hummingbirds on seed production per flower, was assessed by exposing individual flowers to different schedules of visitation by caged flower visitors. In S. mexicana, the number of seeds produced by flowers visited by the robber only was similar to that of flowers visited by the least efficient pollinator but lower than that of those visited by the other pollinators. 4. In F. microphylla, seed production by flowers visited by the robber only was lower than that of flowers visited by all other pollinators. 5. For both plant species visitation by the robber plus hummingbirds yielded a similar number of seeds as flowers visited by the more effective pollinator. 6. There was no field evidence that nectar robbery by D. baritula damages nectaries or ovules and, since under natural conditions flower visitation by the robber only was very rare, we conclude that for these two plant species D. baritula may be regarded as a commensal or even a low-efficiency pollinator.
Bombus terrestris is the first species of bumble bee to become established in Australia. Populations are successfully spreading throughout the island state of Tasmania, following an introduction in the early 1990s. However, there is considerable concern about the possible negative impacts bumble bees may have on Australian ecosystems.
Bee colonies in lowland forest in Panama were monitored for pollen and nectar harvest, pollen species utilization and nectar quality and quantity per returning forager. Despite sharing most pollen resources and nectar of the same quality with 20 introduced colonies of the African honey bee ( Apis mellifera ), native stingless bees of 12 species were largely unaffected by its activity. Pollen and nectar harvested by the honey bees were 10–200 times that procured by 17 stingless bee colonies. This discrepancy in total harvest and general lack of competitive effect is explained by a honey bee foraging area over 10 times that of the native bees, and apparent foraging shifts to escape competition with honey bees, thus reduced potential overlap in foraging sites.
Seven cases of direct resource competition for pollen or nectar were documented, out of 31 tests. Rare periods of intensive harvest were diminished by competing African honey bees. Such harvest peaks lasted for only a few hours in 13 days of observation. Despite average duration of 4% foraging time for each species, peaks included as much as 51% total harvest. Calculations based upon colony populations, food stores and flight range show that if African honey bees persist at a density of 1 colony per km ² , colonies of some stingless bee species may disappear after 10 years. Their chances of escaping food competition by taxonomic specialization on flowers seem slight.
Yield of lucerne seed in New Zealand is very low-less than onetenth that from areas of North America where pollinators are abundant, New Zealand lacks pollinators for lucerne and up to 90% of the florets are not tripped. Two species of bee are cultured in North America exclusively for lucerne pollination, the alkali bee, Nomia melanderi Cockerell, and the lucerne leafcutter bee, Megachile pacifica Panzer. Both species are now established in New Zealand and bee numbers are increasing. For the first time lucerne seed growers in New Zealand can begin to look forward to adequate pollination of their crops.
A leaf-cutter bee, Osmia coerulescens, was able to increase its population when solely on red clover, and so pollinate this important crop plant. Seed yields from Osmia-pollinated plants averaged 440 kg/ha. Data on the sex ratio and the average number of cells produced are given. Mortality of overwintering adults was high.
The introduction and establishment in the United States of species of Eutricharaea (an Old World subgenus of Megachile) are reviewed. A comparison was made by field-cage studies of American and Spanish populations of M. pacifica and an American population of M. concinna. Significant differences included the following. Spanish pacifica showed the lowest mortality in immature stages (9%). M. concinna built about 4 times as many cells as the other bees, and was the most successful in rearing second-generation adults; seed production was also highest in the M. concinna cages. It is important on economic grounds that the possibilities of rearing other alfalfa pollinators than M. pacifica should be explored further.
Megachile (Callomegachile) sculpturalis Smith is recorded from the continental United States for the first time. Presently it is only known in North Carolina where it was presumably introduced from its native range in Japan and China.
Observations on three species of bees showed that, in both red clover and lucerne, there was a significant positive correlation between the temperature and the number of honeybees foraging. The number of B. terrestris foraging was not significantly affected by temperature (11–33°C); on lucerne, there was a highly significant correlation between numbers of honeybees and of B. terrestris, the one robbing nectar and the other collecting pollen. On red clover, pollen foraging by B. ruderatus decreased with increasing temperature, because of increased competition from honeybees. Results are discussed in relation to the pollinating effectiveness of the different groups of foraging bees.
The floral sources of pollen and nectar used by honey bees in Ireland were studied during 1991-1994 by regular two-weekly sampling of pollen pellets from three colonies at a single site, and pollen and nectar samples from four individual colonies at different sites located in mid-western Ireland. Samples were analysed using dry weight and pollen analysis; relative abundance of pollen types was expressed as a percentage of the total number of pollen grains counted and presented as dominance-diversity curves. At the single site, 76 pollen types were identified and a seasonal variation in the dominance of species was apparent. The diversity of species being foraged reached a maximum during June and July. Native nectariferous species were the most important pollen sources, while pollen was also gathered from introduced and entomophilous/anemophilous species especially during spring and early summer. Trees and shrubs were important pollen sources early in the year while herbs and shrubs increased in importance during summer and autumn. A total of 92 pollen types were identified in the pollen and nectar samples at four different sites and this indicates the diversity of plant species foraged by honey bees and the importance of different species as pollen sources, nectar sources or pollen and nectar sources. Honey bee preferences for certain species and individual colony preferences are discussed.
Honey Bee, Apis mellifera, pollen pellets were collected for five days each week for 16 weeks at the University of Guelph. They were sorted by color, the dispersed pollen cleaned by acetolysis and identified under a light microscope. Over 99% of pollen in each pellet was of one pollen type. Twenty-five pollen types were identified. Over 75% of the pellets were pollen from introduced taxa. The pattern of pollen collection by the bees reflected the blooming period of the plants.
We conducted an intensive survey of the bee fauna of Everglades National Park (ENP), Florida. We identified bees (Apoidea) from our field collections (1995-1997) and reviewed published records and collections in regional museums. Sixty-six species of bees occurred in ENP. Thirty-eight additional species were recorded from outside of ENP in Dade and Monroe Counties (total of 104 sp.). The most diverse site in ENP was the Long Pine Key region. Peak diversity was observed from March-April. The numbers of species per family in ENP were: Megachilidae (30), Apidae (17), Halictidae (13), and Colletidae (6). The most diverse genus was Megachile (Megachilidae), with 17 sp. in ENP. Three endemic, two introduced, and twelve parasitic species occurred in ENP. The most diverse parasitic group was Coelioxys (Megachilidae), with 7 sp. present in ENP. The bee fauna is distinct from adjacent tropical areas of the Bahamas, Cuba, and the Yucatan, sharing only a few species with them. Most species in ENP and the region are Nearctic. Compared to northern Florida, the fauna lacks numerous genera and species in the Andrenidae and Apidae. Local and regional differences in bee species composition may reflect lack of suitable ground nesting habitat in ENP.
Utilization of floral resources in native shrublands in the Northern Sandplain of Western Australia by the introduced Apis mellifera was examined. Honey bees used 30% of the 413 species recorded as a source of pollen and/or nectar, preferentially foraging on the most common species. Native bees also favoured species with high relative cover values and foraged on 70% of the 51 plant species visited by honey bees in the same period. Although only 30% of the regional flora are post-fire seed regenerators, these species were preferentially used by both the honey bee and native bee foragers. Fire, especially close-interval recurrent fire, can have a deleterious effect on the major melliferous species. Perennial reseeding species had a higher projective foliage cover than perennial sprouting species, but had lower cover at sites with shorter intervals between fires. A short interval between fires which decreases the local abundance of reseeding species may reduce the ability of a population to attract pollinators and, combined with the effect of a short interval between fires, may lead to the decline and eventual extinction of the population. -from Authors
Previous studies of introduced honey bees foraging at Agave schottii flowers suggest that Apis mellifera preferentially exploits the most productive patches of flowers and thereby reduces the standing crop of available nectar and the utilization of these sites by native bees. Results of experiments undertaken to evaluate this hypothesis are given and discussed using Apis, Bombus and Xylocopa. -Authors
Flower visiting insects were monitored on angiosperm trees in an Araucaria forest in Rio Grande do Sul, Brazil. The most abundant flower visitors were workers of the introduced honey bee, Apis mellifera, followed by stingless bees which were represented by 8 species. Together with other bees, they provide the main guild of foragers on flowering trees. The stingless bee fauna of the study area is similar to that of other regions of the Mata Atlântica, especially of former Araucaria forests, but also of montane coastal rain forests.
Flowers of two neotropical wet lowland forest species, Aphelandra golfodulcensis and Justicia aurea (both Acanthaceae), were visited by both pollinators and floral parasites. Both species were pollinated by the larger hermit hummingbirds and pierced by other bird species and insects (bees and ants). In addition, Trigona sp. bees took pollen from Aphelandra flowers without effecting pollination. The effect of parasitism depends upon a number of factors including frequency of parasitism, impact of parasites on the availability of floral rewards and the response of pollinators to parasitized flowers. Nectar and pollen parasites affected the vast majority of flowers produced in the two study populations: over 90% of flowers of both species had been pierced by noon and more than 90% of Aphelandra flowers had been visited by pollen collecting bees by mid-morning. Pollen parasites frequently caused severe damage to the style as well: about 40% of Aphelandra flowers daily were damaged in this way. Flowers which had been pierced contained less nectar than flowers which had been visited only by pollinators if at all. Visits by nectar parasites left an average 3.5 μ l of nectar more than visits by long-billed hummingbird pollinators. Nectar removed by flower visitors was never fully replaced nor did nectar depletion stimulate subsequent production. Pierced flowers subsequently produced less nectar than legitimately visited flowers such that visits by nectar parasites had the two-fold effect of removing nectar and reducing total nectar secretion. In response to decreased nectar availability due to parasitism, pollinators may partially or completely avoid visits to these populations or may visit more such nectar-poor flowers in order to satisfy their energy requirements. These two very different responses would result in decreased or increased reproductive success, respectively Pollen parasitism of Aphelandra flowers may be of particular significance since if pollen is limiting, even increased visits by pollinators would not result in greater reproductive success. Circumstantial evidence suggests that in both populations floral parasitism has adverse effects on fruit and seed set levels. A result of the explosion of successional communities due to human disturbance may be rather significant changes in the biotic interactions which are especially important in animal-pollinated plant species.
In the evening primrose (Oenothera fruticosa) measurements of the number of pollen grains deposited by each honeybee visit, the number of visits a flower receives and the number of pollen grains necessary to achieve a certain level of seed set allow the prediction that pollinator service is adequate to accomplish complete seed set. The lower than predicted seed set observed in the field may be explained by the transfer of high levels of incompatible pollen.
In an abandoned field near Ithaca, New York, bee species partitioned the available flower resources, primarily by foraging at different times of the season and by visiting different flower species. Honey bees Apis mellifera concentrated on different flower species than did native bees. Spring-flying native bees included many species adapted to forage on native flower species that bloom before the tree canopy closes. Apis mellifera outcompeted native bees at large clusters of attractive flower species such as apple and the crucifer Barbarea vulgaris. Halictus ligatus was the most common early summer halictine. This species concentrated its foraging on different flowers than did other early summer bees, probably because of differences in innate flower preferences. A profuse bloom of native goldenrods Solidago in late summer was the seasonal peak of resource abundance. Native bees must complete their seasonal cycles and enter diapause before the killing frost. They therefore foraged on early-blooming goldenrod species such as S. juncea. In contrast, honey bees overwinter as active bees within their hives. They were most common on later-blooming goldenrods, where they collected much of the nectar required for overwintering. Competition among foraging bees was probably most important in the spring at this site. Partitioning of flower species and differences in seasonal flight times resulted primarily from differences in innate flower preferences, number of generations per season, and means of overwintering.-Author
Competition among three species of bees (Apis mellifera, Bombus sonorus, and Xylocopa arizonensis) visiting Agave schottii was studied. Honeybees were found to predominate in the most productive habitats, Xylocopa in the least; Bombus as most abundant in patches of intermediate quality. It is suggested that these observations are consistent with a simple graphical model relating the standing crop of available nectar to foraging energetics and the additional costs of colonial life (cost of sociality). Temporal variations in foraging behavior were also observed, with Apis again preferring to forage at those times of day (early morning and late afernoon) when resources were most abundant. Bombus was less crepuscular than Apis, and carpenter bees foraged without obvious regard to variation in standing crop. Several factors which may account for this pattern are discussed.
To understand the foraging strategy of honeybee colonies, we measured certain temporal and spatial patterns in the foraging activities of a colony living in a temperate deciduous forest. We monitored foraging activities by housing the colony in an observation hive and reading its recruitment dances to map its food source patches. We found that the colony routinely foraged several kilometres from its nest (median 1.7 km, 95% of foraging within 6.0 km), frequently (at least daily) adjusted its distribution of foragers on its patches, and worked relatively few patches each day (mean of 9.7 patches accounted for 90% of each day's forage). These foraging patterns, together with prior studies on the mechanisms of honeybee recruitment communication, indicate that the foraging strategy of a honeybee colony involves surveying the food source patches within a vast area around its nest, pooling the reconnaissance of its many foragers, and using this information to focus its forager force on a few high-quality patches within its foraging area.
Spatial variation involved differences in reward value among plant species and differences in nectar availability among patches of flowers of a single species. Temporal variation involved changes in nectar availability over a season and between years. Response of bees to different plant species was determined by the density of foraging bees on the flowers of each species at a given time. If bees are optimal foragers, preference should reflect the per- flower reward value of species, characterized by nectar production rates (NPR's). The bees' preference for species was very similar to the relative magnitudes of their NPR's. In general, seasonal floral production and utilization were closely matched, indicating no major change in nectar resource limitation. -from Author
1. Some observations on the interspecific relations between two species of honeybees inhabiting Japan, Apis mellifera L. (introduced) and A. cerana cerana Fabr. (endemic), are described. 2. In general, A. cerana is more tolerant and less aggressive than A. mellifera. 3. It is suggested that robbery by A. mellifera plays an important role in the decrease of A. cerana.
Species flowering during the dry season (late December to early April) form three main pollinator groups, namely, butterfly, solitary bee, and hummingbird flowers. The animal vectors present match these three flower syndromes. The daily and seasonal rhythms of flower opening and pollination activity are synchronized. Butterflies and solitary bees, active chiefly in the morning, visit flowers blooming only half a day. The number of seeds per fruit and the pollen-carrying capacity of the pollen vector are correlated. Butterflies, carrying few pollen grains, chiefly pollinate flowers with one to four seeds. Solitary bees, carrying many grains, chiefly pollinate flowers with many seeds per flower. These close links between the flowers and their visitors result in a high degree of successful pollination and a high percentage fruit set. A group of species, attracting no visitors, was characterized by a very narrow 'pollination gap,' making self-pollination almost inevitable. Heavy fruiting indicated self-fertility. Heterocorollary in Cordia sebestena, a double keel in Stylosanthes hamata, and several examples of andromonoecy are recorded for the first time. The presence of the adventive honeybee, Apis mellifera, in the association appeared detrimental to the native pollinators when forage was scarce. The whole scrub association appears balanced with a distinctive pattern of floral ecology. This circumstance, in terms of pollinators, is designated a Butterfly-Solitary bee-Hummingbird association.
1. Three major determinants of bees' nectar-foraging patterns are the maximum depth at which nectar is accessible (dependent on bee tongue length); the minimum profitable energy content per flower (dependent on foraging costs and hence on bee body mass); and the minimum threshold temperature for flight. These form the axes of a three-dimensional template, the competition box. 2. Thresholds of depth, cost and temperature can be identified for each species of bee, delimiting domains within the box compatible with foraging by each bee species. 3. Changes through a day in temperature and in the depth and sugar content of nectar define the nectar trajectory through the box for a flower species in relation to microclimate and bee activity. 4. This approach allows systematic appraisal of the roles of accessibility, energy content and temperature in interspecific competition among bees for nectar, and draws attention to situations in which additional factors may be important. 5. By superimposing a bee-species-specific template on a representative nectar trajectory for a given flower species in a given situation, it is possible to make reasoned guesses about the expected interactions of foraging bee species with a novel flower species and with each other in a novel situation. Such guesses are required for evaluating the expected impact of honey-bees and other introduced pollinators on the pollination system of crops and natural vegetation. 6. Use of the competition box is illustrated in relation to dawn-to-dusk studies involving measurements of nectar concentration and volume, microclimate, flower form, and the tongue lengths and foraging activity of bees of different species.
Although mutualisms are often viewed as fragile constructs, subject to invasion by ”cheaters” that gain from the mutualism without providing compensating benefits, few studies have explored whether or not apparent cheating behavior by one player actually denies benefits to the other species. Panicled bluebells (Mertensia paniculata) experience high rates of nectar robbery by bumble bees (Bombus mixtus and B. frigidus) in the Wrangell Mountains of southcentral Alaska. Nevertheless, experimental prevention of nectar larceny in two seasons did not enhance components of female reproductive success (nutlet initiation, seed-set, and seed mass) or male success (pollen removal). Observational data show that the absence of a negative impact of nectar robbery is a consequence of bumble bee behaviors; the two bee species that rob mature flowers buzz-pollinate the same flowers at an earlier stage in floral development. The shift in bee behavior is driven by the presentation of different rewards at different times in the flowering period; young flowers contain pollen and older flowers produce nectar. Although flowers typically receive and donate pollen before most nectar is produced, the mature flowers producing a robbed nectar reward may nonetheless contribute to the reproductive success of bluebell plants. Flowers sequestered from pollinators in the early stage were still capable of initiating nutlets, demonstrating that older flowers can enhance female reproduction if pollinators are rare (when many early-stage flowers may go unvisited). Moreover, the removal of mature flowers reduced the visitation rate to early- stage flowers on the same plant. Because individual bumble bees switch frequently between nectar robbing and pollen collection, the nectar reward in mature flowers may act as a key enticement to pollinators, which then enhance plant reproduction by legitimately visiting early-stage flowers. Rather than representing a case of cheating behavior, nectar robbery may be an integral part of this plant-pollinator mutualism.