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Bumblebees are essential, efficient pollinators of numerous crops, and scientists are increasingly concerned about their global decline. Although several potential causes have been put forward, the concurrent modification of landscape structure and pesticide use by agriculture are often pointed out as the main drivers of the decline. Yet, the mechanisms through which these factors cause species to decline remain elusive. Most field studies have been conducted at the individual level and the few studies that addressed higher levels of organization only covered narrow ecological conditions. We undertook a field experiment in spring 2016 to overcome these limitations by placing four commercial Bombus impatiens colonies in each of 20 sites located along a gradient of agricultural intensity in Southern Québec, Canada. We hypothesized that landscape habitat composition and configuration, as well as local floral resources, would affect colony development. We expected colonies surrounded by low intensity and/or flowering crops in heterogeneous landscapes to develop better and live longer, partly linked to more abundant and diversified food resources, than colonies embedded in landscapes dominated by high intensity crops. Colonies were weighed once a week, and workers were captured to assess pollen load diversity. Final colony weight, queen production and presence of depredators (Aphomia sociella, Lepidoptera: Pyralidae) were also recorded. Landscape habitat composition and configuration were characterized within 1 km of colonies. Local availability of floral resources was assessed within 100 m of colonies every two weeks. As predicted, colony weigh and longevity decreased with the proportion of intensive crops and increased with the amount of flowering crops, but queen production and the occurrence of A. sociella were not affected by landscape composition. Contrary to our prediction, local availability of floral resources also did not affect colonies. The pollen richness br

The conservation of bee populations for pollination in agricultural landscapes has attracted a lot of recent research interest, especially for crop industries undergoing expansion to meet increased production demands. In Canada, much growth has been occurring with commercial cranberry production, a field crop which is largely dependent on bee pollination. Wild bee pollinators could be negatively impacted by losses of natural habitat surrounding cranberry fields to accommodate increased production, but growers have little insight on how to manage their lands to maximize the presence of wild bees. Here, we described a 2-yr study where bee diversity and species composition were investigated to better understand the dynamic between natural habitat and cranberry fields. Bees were sampled using pan-traps and hand netting both within cranberry fields and in one of the three adjacent natural habitat types once a week during the crop flowering period. We found that bee community composition among cranberry fields did not differ based on the respective adjacent habitat type, but fields bordered by meadows were marginally less diverse than fields bordered by forest. As one would expect, field and natural habitat communities differed in terms of species composition and species richness. There was no evidence that one type of natural habitat was more favorable for the bees than another. Future agrobiodiversity studies should simultaneously examine bee diversity comprised in both crop fields and adjacent natural environments to better understand the species dynamics essential to the preservation of pollination services.

Flower flies are one of the most important groups of pollinators worldwide. Unfortunately, little is known about their pollination capacity and the importance of their role for many crops grown commercially, such as cranberries. To address this information gap, 12 cranberry farms were sampled during the blooming periods of 2013 and 2014 in Quebec, Canada, to evaluate hoverfly diversity and pollen load. Moreover, the effects of the following three factors on community structure were investigated: farm management (organic vs conventional), edge mowing (mowed vs non-mowed), and type of adjacent natural habitat (forest vs meadow vs bog). Flower flies were captured using pan-traps and hand-netting once a week for 3 wk. In total 461 specimens of flower flies were captured and 33 species were identified. Among the three factors studied, edge mowing explained most of the variation among communities, followed by farm management. Natural habitat type did not appear to influence hoverfly communities, contrary to our expectations and reports from other studies. Pollen load analyses and interactive connectance plot showed that two flower fly species, Syrphus torvus Osten Sacken and Eristalis tenax L. (Diptera: Syrphidae), transported the most cranberry pollen, both in terms of quantity and proportion. To our knowledge, this study is the first to describe and provide a complete list of flower fly species found in cranberry crops. Our results also highlight the importance of floral resource diversity for these potential cranberry pollinators, since edge mowing was revealed to be the most influential of all factors we considered.

Flower flies are one of the most important groups of pollinators worldwide. Unfortunately, little is known about their pollination capacity and the importance of their role for many crops grown commercially, such as cranberries. To address this information gap, 12 cranberry farms were sampled during the blooming periods of 2013 and 2014 in Quebec, Canada, to evaluate hoverfly diversity and pollen load. Moreover, the effects of the following three factors on community structure were investigated: farm management (organic vs conventional), edge mowing (mowed vs non-mowed), and type of adjacent natural habitat (forest vs meadow vs bog). Flower flies were captured using pan-traps and hand-netting once a week for 3 wk. In total 461 specimens of flower flies were captured and 33 species were identified. Among the three factors studied, edge mowing explained most of the variation among communities, followed by farm management. Natural habitat type did not appear to influence hoverfly communities, contrary to our expectations and reports from other studies. Pollen load analyses and interactive connectance plot showed that two flower fly species, Syrphus torvus Osten Sacken and Eristalis tenax L. (Diptera: Syrphidae), transported the most cranberry pollen, both in terms of quantity and proportion. To our knowledge, this study is the first to describe and provide a complete list of flower fly species found in cranberry crops. Our results also highlight the importance of floral resource diversity for these potential cranberry pollinators, since edge mowing was revealed to be the most influential of all factors we considered.

The conservation of bee populations for pollination in agricultural landscapes has attracted a lot of recent research interest, especially for crop industries undergoing expansion to meet increased production demands. In Canada, much growth has been occurring with commercial cranberry production, a field crop which is largely dependent on bee pollination. Wild bee pollinators could be negatively impacted by losses of natural habitat surrounding cranberry fields to accommodate increased production, but growers have little insight on how to manage their lands to maximize the presence of wild bees. Here, we described a 2-yr study where bee diversity and species composition were investigated to better understand the dynamic between natural habitat and cranberry fields. Bees were sampled using pan-traps and hand netting both within cranberry fields and in one of the three adjacent natural habitat types once a week during the crop flowering period. We found that bee community composition among cranberry fields did not differ based on the respective adjacent habitat type, but fields bordered by meadows were marginally less diverse than fields bordered by forest. As one would expect, field and natural habitat communities differed in terms of species composition and species richness. There was no evidence that one type of natural habitat was more favorable for the bees than another. Future agrobiodiversity studies should simultaneously examine bee diversity comprised in both crop fields and adjacent natural environments to better understand the species dynamics essential to the preservation of pollination services.