Sociality is a key driver of foraging ranges in bees

Abstract

Bees are important pollinators of wild and agricultural plants1,2,3,4,5 and there is increasing evidence that many bee populations decline due to a combination of habitat loss, climate change, pesticides, and other anthropogenic effects.6,7,8,9,10,11 One trait that shapes both their role in plant reproduction12,13 and their exposure to anthropogenic stressors is the distance at which bees forage. It has been suggested that bee sociality14 and diet15 affect bee foraging ranges, but how these traits and their potential interactions drive foraging ranges remains unclear. We analyzed flight distance data from 90 bee species and developed an agent-based model to test how social, dietary, and environmental factors affect foraging ranges. We confirm that bee sociality is positively associated with foraging range, with average-sized social bees foraging up to 3 times farther from the nest than size-matched solitary bees. A comparative analysis of social bees and computer simulations shows that foraging distances increase with colony size, supporting the hypothesis that greater foraging distances are an emergent property of increasing colony sizes in a food-limited environment. Flower constancy and communication, two traits often found in social bees, synergistically increase foraging distances further in many simulated environments. Diet breadth (oligolectic versus polylectic diet), on the other hand, does not appear to affect foraging ranges in solitary bees. Our findings suggest that multiple traits linked to bee sociality explain why social bees have greater foraging ranges. This has implications for predicting pollination services and for developing effective conservation strategies for bees and isolated plant populations.15,16,17,18,19.