Evaluating competition for forage plants between honey bees and wild bees in Denmark

A recurrent concern in nature conservation is the potential competition for forage plants between wild bees and managed honey bees. Specifically, that the highly sophisticated system of recruitment and large perennial colonies of honey bees quickly exhaust forage resources leading to the local extirpation of wild bees. However, different species of bees show different preferences for forage plants. We here summarize known forage plants for honey bees and wild bee species at national scale in Denmark. Our focus is on floral resources shared by honey bees and wild bees, with an emphasis on both threatened wild bee species and foraging specialist species. Across all 292 known bee species from Denmark, a total of 410 plant genera were recorded as forage plants. These included 294 plant genera visited by honey bees and 292 plant genera visited by different species of wild bees. Honey bees and wild bees share 176 plant genera in Denmark. Comparing the pairwise niche overlap for individual bee species, no significant relationship was found between their overlap and forage specialization or conservation status. Network analysis of the bee-plant interactions placed honey bees aside from most other bee species, specifically the module containing the honey bee had fewer links to any other modules, while the remaining modules were more highly inter-connected. Despite the lack of predictive relationship from the pairwise niche overlap, data for individual species could be summarized. Consequently, we have identified a set of operational parameters that, based on a high foraging overlap (>70%) and unfavorable conservation status (Vulnerable+Endangered+Critically Endangered), can guide both conservation actions and land management decisions in proximity to known or suspected populations of these species.

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Identity of mass-flowering crops moderates functional trait composition of pollinator communities

Landscape Ecology ◽

10.1007/s10980-021-01261-3 ◽

2021 ◽

Author(s):

Nicole Beyer ◽

Felix Kirsch ◽

Doreen Gabriel ◽

Catrin Westphal

Keyword(s):

Faba Bean ◽

Management Practices ◽

Functional Trait ◽

Flower Morphology ◽

Landscape Diversity ◽

Floral Resources ◽

Wild Bees ◽

Natural Habitats ◽

Mass Flowering ◽

Wild Bee

Abstract Context Pollinator declines and functional homogenization of farmland insect communities have been reported. Mass-flowering crops (MFC) can support pollinators by providing floral resources. Knowledge about how MFC with dissimilar flower morphology affect functional groups and functional trait compositions of wild bee communities is scarce. Objective We investigated how two morphologically different MFC, land cover and local flower cover of semi-natural habitats (SNH) and landscape diversity affect wild bees and their functional traits (body size, tongue length, sociality, foraging preferences). Methods We conducted landscape-level wild bee surveys in SNH of 30 paired study landscapes covering an oilseed rape (OSR) (Brassica napus L.) gradient. In 15 study landscapes faba beans (Vicia faba L.) were grown, paired with respective control landscapes without grain legumes. Results Faba bean cultivation promoted bumblebees (Bombus spp. Latreille), whereas non-Bombus densities were only driven by the local flower cover of SNH. High landscape diversity enhanced wild bee species richness. Faba bean cultivation enhanced the proportions of social wild bees, bees foraging on Fabaceae and slightly of long-tongued bumblebees. Solitary bee proportions increased with high covers of OSR. High local SNH flower covers mitigated changes of mean bee sizes caused by faba bean cultivation. Conclusions Our results show that MFC support specific functional bee groups adapted to their flower morphology and can alter pollinators` functional trait composition. We conclude that management practices need to target the cultivation of functionally diverse crops, combined with high local flower covers of diverse SNH to create heterogeneous landscapes, which sustain diverse pollinator communities.

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Noncrop Habitat Use by Wild Bees (Hymenoptera: Apoidea) in a Mixed-Use Agricultural Landscape

Environmental Entomology ◽

10.1093/ee/nvaa001 ◽

2020 ◽

Vol 49 (2) ◽

pp. 502-515 ◽

Cited By ~ 1

Author(s):

Brianne Du Clos ◽

Francis A Drummond ◽

Cynthia S Loftin

Keyword(s):

United States ◽

Floral Resources ◽

Northeastern United States ◽

Wild Bees ◽

Wild Bee ◽

Lowbush Blueberry ◽

Mixed Use ◽

Abundance And Diversity ◽

Bee Communities ◽

Bee Abundance

Abstract Homogeneous, agriculturally intense landscapes have abundant records of pollinator community research, though similar studies in the forest-dominated, heterogeneous mixed-use landscape that dominates the northeastern United States are sparse. Trends of landscape effects on wild bees are consistent across homogeneous agricultural landscapes, whereas reported studies in the northeastern United States have not found this consistency. Additionally, the role of noncrop habitat in mixed-use landscapes is understudied. We assessed wild bee communities in the mixed-use lowbush blueberry (Vaccinium angustifolium Ait.) production landscape of Maine, United States at 56 sites in eight land cover types across two regional landscapes and analyzed effects of floral resources, landscape pattern, and spatial scale on bee abundance and species richness. Within survey sites, cover types with abundant floral resources, including lowbush blueberry fields and urban areas, promoted wild bee abundance and diversity. Cover types with few floral resources such as coniferous and deciduous/mixed forest reduced bee abundance and species richness. In the surrounding landscape, lowbush blueberry promoted bee abundance and diversity, while emergent wetland and forested land cover strongly decreased these measures. Our analysis of landscape configuration revealed that patch mixing can promote wild bee abundance and diversity; however, this was influenced by strong variation across our study landscape. More surveys at intra-regional scales may lead to better understanding of the influence of mixed-use landscapes on bee communities.

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Diversified Farming in a Monoculture Landscape: Effects on Honey Bee Health and Wild Bee Communities

Environmental Entomology ◽

10.1093/ee/nvaa031 ◽

2020 ◽

Vol 49 (3) ◽

pp. 753-764 ◽

Cited By ~ 1

Author(s):

Ashley L St. Clair ◽

Ge Zhang ◽

Adam G Dolezal ◽

Matthew E O’Neal ◽

Amy L Toth

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Natural Habitat ◽

Colony Growth ◽

Nutritional State ◽

Floral Resources ◽

Fruit And Vegetable ◽

Wild Bee ◽

Bee Conservation ◽

Bee Communities

Abstract In the last century, a global transformation of Earth’s surface has occurred due to human activity with extensive agriculture replacing natural ecosystems. Concomitant declines in wild and managed bees are occurring, largely due to a lack of floral resources and inadequate nutrition, caused by conversion to monoculture-based farming. Diversified fruit and vegetable farms may provide an enhanced variety of resources through crops and weedy plants, which have potential to sustain human and bee nutrition. We hypothesized fruit and vegetable farms can enhance honey bee (Hymenoptera: Apidae, Apis mellifera Linnaeus) colony growth and nutritional state over a soybean monoculture, as well as support a more diverse wild bee community. We tracked honey bee colony growth, nutritional state, and wild bee abundance, richness, and diversity in both farm types. Honey bees kept at diversified farms had increased colony weight and preoverwintering nutritional state. Regardless of colony location, precipitous declines in colony weight occurred during autumn and thus colonies were not completely buffered from the stressors of living in a matrix dominated with monocultures. Contrary to our hypothesis, wild bee diversity was greater in soybean, specifically in August, a time when fields are in bloom. These differences were largely driven by four common bee species that performed well in soybean. Overall, these results suggest fruit and vegetable farms provide some benefits for honey bees; however, they do not benefit wild bee communities. Thus, incorporation of natural habitat, rather than diversified farming, in these landscapes, may be a better choice for wild bee conservation efforts.

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Evaluation of Selected Ornamental Asteraceae as a Pollen Source for Urban Bees

Journal of Apicultural Science ◽

10.1515/jas-2016-0031 ◽

2016 ◽

Vol 60 (2) ◽

pp. 179-192 ◽

Cited By ~ 1

Author(s):

Anna Wróblewska ◽

Ernest Stawiarz ◽

Marzena Masierowska

Keyword(s):

Honey Bees ◽

Pollen Grains ◽

Bumble Bees ◽

Floral Resources ◽

Tagetes Patula ◽

Single Plant ◽

Calendula Officinalis ◽

Wild Bees ◽

Se Poland ◽

Urban Conditions

Abstract Offering more floral resources for urban bees can be achieved by growing ornamental bee plants. The aim of the present study was to evaluate selected Asteraceae (Calendula officinalis ‘Persimmon Beauty’ and ‘Santana’, Centaurea macrocephala, Cosmos sulphureus, Dahlia pinnata, Tagetes patula, Tithonia rotundifolia, and Zinnia elegans) as pollen sources for pollinators. Under urban conditions in Lublin, SE Poland, the investigated plants flowered from late June to the end of October. The mass of pollen produced in florets and capitula was found to be species-related. The highest pollen amounts per 10 florets (10.1 mg) as well as per capitulum (249.7 mg) were found for C. macrocephala. The mass of pollen yielded by a single plant depended on both the pollen mass delivered per disk florets and the proportion of disk florets in capitulum, and the flowering abundance of the plants. A single plant of D. pinnata and a single plant of T. rotundifolia each produced the largest pollen mass. Mean pollen yield per 1m2 of a plot ranged from 6.2 g (Z. elegans) to 60.7 g (D. pinnata). Pollen grains are tricolporate, with echinate exine, medium or small in size. They can be categorised as oblatespherical, spherical, and prolatespherical. The principal visitors to C. macrocephala, C. sulphureus, and C. officinalis were honey bees, whereas bumble bees dominated on T. rotundifolia and D. pinnata. A magnet plant for butterflies was Z. elegans. Among the investigated species, D. pinnata, C. macrocephala, and T. rotundifolia were found to be the most valuable sources of pollen flow for managed and wild bees.

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Bumble bees influence berry size in commercial Vaccinium spp. cultivation in British Columbia

The Canadian Entomologist ◽

10.4039/n07-065 ◽

2008 ◽

Vol 140 (3) ◽

pp. 348-363 ◽

Cited By ~ 23

Author(s):

Claudia M. Ratti ◽

Heather A. Higo ◽

Terry L. Griswold ◽

Mark L. Winston

Keyword(s):

British Columbia ◽

Honey Bees ◽

Vaccinium Corymbosum ◽

Bumble Bees ◽

Wild Bees ◽

Wild Bee ◽

Berry Size ◽

Dispersion Patterns ◽

Potential Alternative ◽

Fraser Valley

AbstractWe studied the abundance, diversity, and dispersion patterns of managed and wild bee (Hymenoptera: Apoidea) populations in commercial highbush blueberry and cranberry (Ericaceae: Vaccinium corymbosum L., Vaccinium macrocarpon Ait.) fields in the Fraser Valley of British Columbia, and assessed their potential as pollinators of these crops by determining which groups of bees had the greatest impact on percent yield and mass of berries. Bumble bees were evenly distributed within both crops. Other wild bee species were well distributed in blueberry fields but generally remained at edges of cranberry fields. Percent berry yield was not related to bee abundance for any group of bees, nor was species diversity correlated with berry mass. Blueberry mass and cranberry mass were related to abundance of bumble bees but not to that of honey bees or other wild bees. Bumble bees are recommended as potential alternative pollinators of these crops.

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Diverse Diets with Consistent Core Microbiome in Wild Bee Pollen Provisions

Insects ◽

10.3390/insects11080499 ◽

2020 ◽

Vol 11 (8) ◽

pp. 499

Author(s):

Rebecca M. Dew ◽

Quinn S. McFrederick ◽

Sandra M. Rehan

Keyword(s):

Amplicon Sequencing ◽

Floral Resources ◽

Wild Bees ◽

Pollination Services ◽

Core Microbiome ◽

Carpenter Bee ◽

Wild Bee ◽

Ceratina Calcarata ◽

Plant Pollen ◽

Small Carpenter Bee

Bees collect pollen from flowers for their offspring, and by doing so contribute critical pollination services for our crops and ecosystems. Unlike many managed bee species, wild bees are thought to obtain much of their microbiome from the environment. However, we know surprisingly little about what plant species bees visit and the microbes associated with the collected pollen. Here, we addressed the hypothesis that the pollen and microbial components of bee diets would change across the range of the bee, by amplicon sequencing pollen provisions of a widespread small carpenter bee, Ceratina calcarata, across three populations. Ceratina calcarata was found to use a diversity of floral resources across its range, but the bacterial genera associated with pollen provisions were very consistent. Acinetobacter, Erwinia, Lactobacillus, Sodalis, Sphingomonas and Wolbachia were among the top ten bacterial genera across all sites. Ceratina calcarata uses both raspberry (Rubus) and sumac (Rhus) stems as nesting substrates, however nests within these plants showed no preference for host plant pollen. Significant correlations in plant and bacterial co-occurrence differed between sites, indicating that many of the most common bacterial genera have either regional or transitory floral associations. This range-wide study suggests microbes present in brood provisions are conserved within a bee species, rather than mediated by climate or pollen composition. Moving forward, this has important implications for how these core bacteria affect larval health and whether these functions vary across space and diet. These data increase our understanding of how pollinators interact with and adjust to their changing environment.

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Are Bumblebees Relevant Models for Understanding Wild Bee Decline?

Frontiers in Conservation Science ◽

10.3389/fcosc.2021.752213 ◽

2021 ◽

Vol 2 ◽

Author(s):

Guillaume Ghisbain

Keyword(s):

Environmental Changes ◽

Conservation Status ◽

Diet Breadth ◽

Activity Period ◽

Population Declines ◽

Wild Bees ◽

Wild Bee ◽

Conservation Actions ◽

Level Of Understanding ◽

Bee Decline

The unsustainable use of ecosystems by human societies has put global biodiversity in peril. Bees are, in this context, a popular example of a highly diversified group of pollinators whose collapse is a major concern given the invaluable ecosystem services they provide. Amongst them, bumblebees (Bombus) have increasingly drawn the attention of scientists due to their dramatic population declines globally. This regression has converted them into popular conservation entities, making them the second most studied group of bees worldwide. However, in addition to have become relevant models in the fields of ecology, evolution and biogeography, bumblebees have also been used as models for studying wild bee decline and conservation worldwide. Integrating evidence from the comparative ecology and resilience of bumblebees and wild bees, I discuss the relevance of using Bombus as radars for wild bee decline worldwide. Responses of bumblebees to environmental changes are generally not comparable with those of wild bees because of their relatively long activity period, their inherent sensitivity to high temperatures, their relatively generalist diet breadth and many aspects arising from their eusocial behavior. Moreover, important differences in the available historical data between bumblebees and other bees make comparisons of conservation status even more arduous. Overall, these results reinforce the need for conservation actions that consider a higher level of understanding of ecological diversity in wild bees, highlight the need for an updated and more extensive sampling of these organisms, and emphasize that more caution is required when extrapolating trends from model species.

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Possible Spillover of Pathogens between Bee Communities Foraging on the Same Floral Resource

Insects ◽

10.3390/insects12020122 ◽

2021 ◽

Vol 12 (2) ◽

pp. 122

Author(s):

Anne Dalmon ◽

Virgine Diévart ◽

Maxime Thomasson ◽

Romain Fouque ◽

Bernard E. Vaissière ◽

...

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Population Decline ◽

Virus Transmission ◽

Wild Bees ◽

Deformed Wing Virus ◽

Wild Bee ◽

Pollinator Community ◽

Floral Resource ◽

Paralysis Virus

Viruses are known to contribute to bee population decline. Possible spillover is suspected from the co-occurrence of viruses in wild bees and honey bees. In order to study the risk of virus transmission between wild and managed bee species sharing the same floral resource, we tried to maximize the possible cross-infections using Phacelia tanacetifolia, which is highly attractive to honey bees and a broad range of wild bee species. Virus prevalence was compared over two years in Southern France. A total of 1137 wild bees from 29 wild bee species (based on COI barcoding) and 920 honey bees (Apis mellifera) were checked for the seven most common honey bee RNA viruses. Halictid bees were the most abundant. Co-infections were frequent, and Sacbrood virus (SBV), Black queen cell virus (BQCV), Acute bee paralysis virus (ABPV) and Israeli acute paralysis virus (IAPV) were widespread in the hymenopteran pollinator community. Conversely, Deformed wing virus (DWV) was detected at low levels in wild bees, whereas it was highly prevalent in honey bees (78.3% of the samples). Both wild bee and honey bee virus isolates were sequenced to look for possible host-specificity or geographical structuring. ABPV phylogeny suggested a specific cluster for Eucera bees, while isolates of DWV from bumble bees (Bombus spp.) clustered together with honey bee isolates, suggesting a possible spillover.

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Reduced nest development of reared Bombus terrestris within apiary dense human-modified landscapes

Scientific Reports ◽

10.1038/s41598-021-82540-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ivan Meeus ◽

Laurian Parmentier ◽

Matti Pisman ◽

Dirk C. de Graaf ◽

Guy Smagghe

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Bombus Terrestris ◽

Global Scale ◽

Bumble Bees ◽

Wild Bees ◽

Wild Bee ◽

Important Trait ◽

Competition For Resources ◽

Biomass Increase

AbstractWild bees are in decline on a local to global scale. The presence of managed honey bees can lead to competition for resources with wild bee species, which has not been investigated so far for human-modified landscapes. In this study we assess if managed honey bee hive density influence nest development (biomass) of bumble bees, an important trait affecting fitness. We hypothesize that domesticated honey bees can negatively affect Bombus terrestris nest development in human-modified landscapes. In Flanders, Belgium, where such landscapes are dominantly present, we selected 11 locations with landscape metrics ranging from urban to agricultural. The bee hive locations were mapped and each location contained one apiary dense (AD) and one apiary sparse (AS) study site (mean density of 7.6 ± 5.7 managed honey bee hives per km2 in AD sites). We assessed the effect of apiary density on the reproduction of reared B. terrestris nests. Reared B. terrestris nests had more biomass increase over 8 weeks in apiary sparse (AS) sites compared to nests located in apiary dense (AD) sites. This effect was mainly visible in urban locations, where nest in AS sites have 99.25 ± 60.99 g more biomass increase compared to nest in urban AD sites. Additionally, we found that managed bumble bee nests had higher biomass increase in urban locations. We conclude that the density of bee hives is a factor to consider in regard to interspecific competition between domesticated honey bees and bumble bees.

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Novel data support model linking floral resources and honey bee competition with bumble bee abundances in coastal scrub

Journal of Pollination Ecology ◽

10.26786/1920-7603(2021)625 ◽

2021 ◽

Vol 27 ◽

Author(s):

Diane M Thomson

Keyword(s):

Apis Mellifera ◽

Statistical Model ◽

Honey Bees ◽

Floral Resources ◽

Bumble Bee ◽

Mechanistic Models ◽

Pollination Services ◽

Forage Plants ◽

Time Period ◽

Floral Resource

Growing evidence supports that many bee populations are declining, with potentially serious consequences for pollination services. Mechanistic models that predict bee abundances from drivers like floral resource availability can be a powerful way to understand and address declines, but remain rare and largely unvalidated. I used temporally and spatially novel data to validate previous analyses linking bumble bee (Bombus spp.) declines in California coastal scrub with loss of floral resources, mediated by drought and competition with non-native honey bees (Apis mellifera). New observations from 2015-2018 were combined with data from 1999-2014 to further test these mechanistic hypotheses and evaluate predictions of a statistical model for Bombus abundances. As predicted, positive associations between spring rainfall and floral abundances and between Bombus and key forage plants were consistent between time periods. Increased A. mellifera abundance corresponded with reduced Bombus use of the most abundant forage plant and lower Bombus abundances in the following year. Quantitative predictions from the Bombus statistical model previously developed for 1999-2014 were relatively unbiased and strongly rank correlated with either spatially or temporally novel data. However, the model consistently underpredicted Bombus abundances when both flower patch and time period were novel. Overall, four new years of data further strengthen evidence that loss of floral resources due to drought and competition with feral Apis mellifera is an important cause of Bombus decline in this habitat. These findings reinforce the value of even simple models that are mechanistically framed, both in understanding past patterns of change and for qualitative prediction.

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