Wild Bee Visitation Rates Exceed Pollination Thresholds in Commercial Cucurbita Agroecosystems

2019 ◽  
Vol 113 (2) ◽  
pp. 562-574 ◽  
Author(s):  
C M McGrady ◽  
R Troyer ◽  
S J Fleischer

Abstract Wild bees supply sufficient pollination in Cucurbita agroecosystems in certain settings; however, some growers continue to stock fields with managed pollinators due to uncertainties of temporal and spatial variation on pollination services supplied by wild bees. Here, we evaluate wild bee pollination activity in wholesale, commercial pumpkin fields over 3 yr. We identified 37 species of bees foraging in commercial pumpkin fields. Honey bees (Apis mellifera L. [Hymenoptera: Apidae]), squash bees (Eucera (Peponapis) Say, Dorchin [Hymenoptera: Apidae]), and bumble bees (Bombus spp., primarily B. impatiens Cresson [Hymenoptera: Apidae]) were the most active pollinator taxa, responsible for over 95% of all pollination visits. Preference for female flowers decreased as distance from field edge increased for several bee taxa. Visitation rates from one key pollinator was negatively affected by field size. Visitation rates for multiple taxa exhibited a curvilinear response as the growing season progressed and responded positively to increasing floral density. We synthesized existing literature to estimate minimum ‘pollination thresholds’ per taxa and determined that each of the most active pollinator taxa exceeded these thresholds independently. Under current conditions, renting honey bee hives may be superfluous in this system. These results can aid growers when executing pollination management strategies and further highlights the importance of monitoring and conserving wild pollinator populations.

Author(s):  
Rachel A. Nalepa ◽  
Graham Epstein ◽  
Jeremy Pittman ◽  
Sheila R. Colla

Abstract Pollination services are critical for food production. Although domesticated honey bees are important pollinators in agriculture, there is growing interest in supporting naturally occurring wild bees. Diversifying pollination management strategies by encouraging healthy wild bee communities may be especially useful for growers of insect-pollinated crops, such as apples. Although research has identified several land management practices that can enhance local pollinator communities on farms, there are few studies on the factors that influence growers to adopt pollinator-supporting actions on their land. Here, we surveyed 75 Canadian apple growers and used regression models to explore the influence of farm characteristics and perceptions about bees on the likelihood of adopting 15 unique pollinator-supporting practices. We also provide a descriptive analysis of growers' pollination management practices and self-assessed resourcefulness on the ability to improve habitat for wild pollinators on the farm. We found that an increase in three variables: awareness of wild bees, perception of the severity of threats facing wild populations, and the perception of the benefits provided by wild bees is associated with more pollinator-supporting practices on the farm. Overall, growers were less likely to adopt pollinator-friendly practices as the fraction of rented land increased and as the perceived costs of implementing these practices rose. We found ‘low-hanging fruit’ (i.e., pollinator-supporting practices that could be easily and inexpensively implemented) were adopted by less than one-third of growers and that the majority of those surveyed had little to no knowledge on what actions to take if they wanted to improve their farms for wild bees or where to go for that knowledge. Our results suggest that policies and programs that focus on raising grower awareness of wild bees, increasing grower perception of their benefits, and reducing the perceived costs of implementing pollinator-supporting practices may positively affect their uptake. A deeper understanding of grower perceptions will provide essential insight into how growers may contribute to wild pollinator conservation while potentially increasing agricultural production and reducing vulnerability borne of heavy reliance on managed pollinators.


2021 ◽  
Vol 9 ◽  
Author(s):  
Panlong Wu ◽  
Piaopiao Dai ◽  
Meina Wang ◽  
Sijie Feng ◽  
Aruhan Olhnuud ◽  
...  

Bees provide key pollination services for a wide range of crops. Accumulating evidence shows the effect of semi-natural habitats at the landscape level and local management practices on bee diversity in fields. However, most of the evidence is derived from studies in North America and Europe. Whether this paradigm is applicable in China, which is characterized by smallholder-dominated agricultural landscapes, has rarely been studied. In this study, we aimed to investigate how bee diversity affected apple production, and how landscape and local variables affected bee diversity and species composition on the Northern China Plain. The results showed that bees significantly increased apple fruit set compared to bagged controls. Wild bee diversity was positively related to apple seed numbers. Higher seed numbers reduced the proportion of deformed apples and thus increased fruit quality. Wild bee abundance was positively correlated with flowering ground cover, and both the abundance and species richness of wild bees were positively affected by the percentage of semi-natural habitats. We conclude that apple quality can benefit from ecological intensification comprising the augmentation of wild bees by semi-natural habitats and flowering ground cover. Future pollination management should therefore reduce the intensification level of management at both the local and landscape scales.


Data ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 98 ◽  
Author(s):  
Kathleen A Lewis ◽  
John Tzilivakis

Pollination services are vital for agriculture, food security and biodiversity. Although many insect species provide pollination services, honeybees are thought to be the major provider of this service to agriculture. However, the importance of wild bees in this respect should not be overlooked. Whilst regulatory risk assessment processes have, for a long time, included that for pollinators, using honeybees (Apis mellifera) as a protective surrogate, there are concerns that this approach may not be sufficiently adequate particularly because of global declines in pollinating insects. Consequently, risk assessments are now being expanded to include wild bee species such as bumblebees (Bombus spp.) and solitary bees (Osmia spp.). However, toxicity data for these species is scarce and are absent from the main pesticide reference resources. The aim of the study described here was to collate data relating to the acute toxicity of pesticides to wild bee species (both topical and dietary exposure) from published regulatory documents and peer reviewed literature, and to incorporate this into one of the main online resources for pesticide risk assessment data: The Pesticide Properties Database, thus ensuring that the data is maintained and continuously kept up to date. The outcome of this study is a dataset collated from 316 regulatory and peer reviewed articles that contains 178 records covering 120 different pesticides and their variants which includes 142 records for bumblebees and a further 115 records for other wild bee species.


2018 ◽  
Vol 3 (1) ◽  
pp. 393-403 ◽  
Author(s):  
E. M. Venturini ◽  
F. A. Drummond ◽  
A. K. Hoshide

Abstract Pollination reservoirs are pollen and nectar rich wildflower plantings intended to enhance pollination services in pollinator-dependent crops. Despite government assistance, plantings often fail to establish. Our focal crop, wild blueberries, is a unique cropping-system native to the U.S.A. It is never planted or cultivated, and typically exists in isolated fields within a mostly coniferous forest matrix. Our study takes place in Maine, U.S.A., where growers could economically benefit by switching reliance from rented honey bees to native bee pollination. Lowbush blueberry growers support wild bee enhancement efforts, but the low pH (4.0-5.0) of this agro-ecosystem presents unique challenges to wildflower establishment. We sought to identify methods that Organic certified growers can use to successfully establish pollination reservoirs in this system. We tested the effects of nurse crops and mowing on the success of a custom wildflower mixture over four years. Success was considered in terms of longevity, sown species diversity, above-ground biomass, and the number and weight of inflorescences. The authors present an economic analysis of cost versus projected planting longevity. In the fourth year of establishment, sown plant diversity significantly decreased, Solidago spp. weeds became dominant, and treatments were not a strong determinant of planting success. The economic analysis suggests that the high cost of pollination reservoir establishment may be a barrier to grower adoption. This study provides evidence and economic justification that weeds must be controlled prior to planting and represents one of the first studies to empirically test organic strategies for wildflower establishment in an agricultural context.


2015 ◽  
Vol 6 (1) ◽  
Author(s):  
David Kleijn ◽  
Rachael Winfree ◽  
Ignasi Bartomeus ◽  
Luísa G Carvalheiro ◽  
Mickaël Henry ◽  
...  

Abstract There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.


Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 499
Author(s):  
Rebecca M. Dew ◽  
Quinn S. McFrederick ◽  
Sandra M. Rehan

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.


2015 ◽  
Vol 282 (1809) ◽  
pp. 20150299 ◽  
Author(s):  
Mia G. Park ◽  
E. J. Blitzer ◽  
Jason Gibbs ◽  
John E. Losey ◽  
Bryan N. Danforth

Wild bee communities provide underappreciated but critical agricultural pollination services. Given predicted global shortages in pollination services, managing agroecosystems to support thriving wild bee communities is, therefore, central to ensuring sustainable food production. Benefits of natural (including semi-natural) habitat for wild bee abundance and diversity on farms are well documented. By contrast, few studies have examined toxicity of pesticides on wild bees, let alone effects of farm-level pesticide exposure on entire bee communities. Whether beneficial natural areas could mediate effects of harmful pesticides on wild bees is also unknown. Here, we assess the effect of conventional pesticide use on the wild bee community visiting apple ( Malus domestica ) within a gradient of percentage natural area in the landscape. Wild bee community abundance and species richness decreased linearly with increasing pesticide use in orchards one year after application; however, pesticide effects on wild bees were buffered by increasing proportion of natural habitat in the surrounding landscape. A significant contribution of fungicides to observed pesticide effects suggests deleterious properties of a class of pesticides that was, until recently, considered benign to bees. Our results demonstrate extended benefits of natural areas for wild pollinators and highlight the importance of considering the landscape context when weighing up the costs of pest management on crop pollination services.


2019 ◽  
Vol 7 ◽  
Author(s):  
Casey Delphia ◽  
Terry Griswold ◽  
Elizabeth Reese ◽  
Kevin O'Neill ◽  
Laura Burkle

Over three years (2013-2015), we sampled bees using nets and bowl traps on four diversified vegetable farms in Gallatin County, Montana, USA, as part of a study evaluating the use of wildflower strips for supporting wild bees and crop pollination services on farmlands (Delphia et al. In prep). We document 202 species and morphospecies from 32 genera within five families, of which 25 species represent the first published state records for Montana. This study increases our overall understanding of the distribution of wild bee species associated with agroecosystems of the northern US Rockies, which is important for efforts aimed at conserving bee biodiversity and supporting sustainable crop pollination systems on farmlands.We provide a species list of wild bees associated with diversified farmlands in Montana and increase the number of published bee species records in the state from 374 to at least 399. The list includes new distributional records for 25 wild bee species, including two species that represent considerable expansions of their known ranges, Lasioglossum (Dialictus) clematisellum (Cockerell 1904) with previously published records from New Mexico, Arizona, California and Utah and Melissodes (Eumelissodes) niveus Robertson 1895 which was reported to range from New York to Minnesota and Kansas, south to North Carolina, Alabama and Mississippi.


Environments ◽  
2018 ◽  
Vol 5 (9) ◽  
pp. 98 ◽  
Author(s):  
Aaron Hoshide ◽  
Francis Drummond ◽  
Thomas Stevens ◽  
Eric Venturini ◽  
Samuel Hanes ◽  
...  

Pollinator conservation efforts and growing interest in wild bee pollination have increased markedly in the last decade, making it increasingly important to have clear and practical estimates of the value of pollinators to agriculture. We used agricultural statistics, socio-economic producer surveys, and agronomic field research data to estimate traditional pollination value metrics and create novel approaches to the valuation of the ecosystem services provided by wild pollinators. Using two regionally important United States (USA) crops—Maine wild blueberry and Massachusetts cranberry—as models, we present the perceived values of wild bee pollinators from the perspectives of both consumers and producers. The net income attributable to wild bees was similar for wild blueberry ($613/ha) and cranberry ($689/ha). Marginal profit from incrementally adding more hives per ha was greater from stocking a third/fourth hive for cranberry ($6206/ha) than stocking a ninth/10th hive for wild blueberry ($556/ha), given the greater initial responsiveness of yield, revenue, and profit using rented honey bee hives in cranberry compared with wild blueberry. Both crops’ producers were willing to annually invest only $140–188/ha in wild pollination enhancements on their farms, justifying government financial support. Consumers are willing to pay ≈6.7 times more to support wild bees than producers, which indicates a potential source for market-based subsidies for invertebrate conservation.


2015 ◽  
Vol 211 ◽  
pp. 51-56 ◽  
Author(s):  
Heather Connelly ◽  
Katja Poveda ◽  
Gregory Loeb

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