Bumble bee communities are strongly disrupted worldwide through the population decline of many species; a phenomenon that has been generally attributed to landscape modification, pesticide use, pathogens, and climate change. The mechanisms by which these causes act on bumble bee colonies are, however, likely to be complex and to involve many levels of organization spanning from the community down to the least understood individual level. Here, we assessed how the morphology, weight and foraging behavior of individual workers are affected by their surrounding landscape. We hypothesized that colonies established in landscapes showing high cover of intensive crops and low cover of flowering crops, as well as low amounts of local floral resources, would produce smaller workers, which would perform fewer foraging trips and collect pollen loads less constant in species composition. We tested these predictions with 80 colonies of commercially reared Bombus impatiens Cresson placed in 20 landscapes spanning a gradient of agricultural intensification in southern Québec, Canada. We estimated weekly rate at which workers entered and exited colonies and captured eight workers per colony over a period of 14 weeks during the spring and summer of 2016. Captured workers had their wing, thorax, head, tibia, and dry weight measured, as well as their pollen load extracted and identified to the lowest possible taxonomic level. We did not detect any effect of landscape habitat composition on worker morphology or body weight, but found that foraging activity decreased with intensive crops. Moreover, higher diversity of local floral resources led to lower pollen constancy in intensively cultivated landscapes. Finally, we found a negative correlation between the size of workers and the diversity of their pollen load. Our results provide additional evidence that conservation actions regarding pollinators in arable landscapes should be made at the landscape rather than at the farm level.

While evidence of insect pollinator declines accumulates, little is known about the pollinator communities that are most vulnerable to population fluctuations and may require conservation actions. Among the main reasons for this lack of knowledge about the status and trends of native pollinators are the time, cost, and expertise required to collect and identify wild insect pollinators (bees, more specifically). Here, we discuss how leveraging the complementarity of community science and taxonomist expertise can help overcome these challenges and provide perspective and insights from launching the large‐scale monitoring program Abeilles citoyennes . The overall objective of this community science project is to monitor wild bee (Apoidea) and hover fly (Syrphidae) diversity in the province of Quebec, Canada, and study the effects of landscape composition on their communities. From 2019 to 2021, 131 volunteers collected insects at 161 sites across the province. A total of 13,558 bees and 2,486 hover flies were collected and identified to species. The project protocol and potential data uses are presented, along with a discussion of the benefits and challenges of using an expert‐assisted community science approach for pollinator monitoring and opportunities for improvement.

Bumble bees are among the most effective pollinators in orchards during the blooming period, yet they are often threatened by the high levels of pesticide use in apple production. This study aimed to evaluate the influence of landscape enhancements (e.g., hedgerows, flower strips) on bumble bee queens in apple orchards. Bumble bee queens from 12 orchards in southern Québec (Canada) were marked, released, and recaptured in the springs and falls of 2017 to 2019. Half of the 12 orchards had landscape enhancements. Apples were harvested in 2018 and 2019 to compare their quality (weight, diameter, sugar level, and seed number) in sites with and without landscape enhancements. Species richness, as well as the occurrence of three species out of eight, was higher in orchards with landscape enhancements than in orchards without such structures. The occurrence of Bombus ternarius was lower in orchards with high levels of pesticide use. Apples had fewer seeds when collected in orchards with landscape enhancements and were heavier in orchards that used more pesticides. Our work provides additional evidence that landscape enhancements improve bumble bee presence in apple orchards and should therefore be considered as a means to enhance pollination within farms.

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.

Bumble bees 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 weight 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 brought back to colonies decreased with the proportion of flowering crops and varied according to the proportion of intensive crops interacting with local floral resources. Our work contributes to generalize the more restrictive conclusion of local‐scale, crop‐specific studies that intensive crop farming undermines bumble bee colony development and that it may thus play a role in the large‐scale population decline of these insects.