Social isolation is associated with distinct cuticular chemistry in bumble bees

Abstract

Cuticular hydrocarbons (CHCs) support desiccation resistance and chemical communication in insects. Across social insects, CHCs also play a role in nestmate recognition, fertility signaling, and other aspects of social communication. Social experience heavily influences cuticular chemistry. Isolation can disrupt the social signals that are typically used to communicate with nestmates, though little is understood about how social experience intersects with reproductivity and dominance. Here, we examine the effects of early-life social experience on cuticular chemistry in the common eastern bumble bee, Bombus impatiens. We compared head and abdomen cuticular extracts of size-, colony-, and age-matched 7-day-old workers reared from eclosion in isolation or in small, social groups containing four workers. We identified 51 unique compounds and substantial differences between cuticular extracts of socially-reared and isolated workers in both tissues. Isolated bees also exhibited significantly less ovarian development, reduced egg laying, and minimal honeypot and egg-cell construction compared to their socially-reared counterparts. In B. impatiens, we found that CHCs are associated with both reproductive state and social signaling, but their effects are strongly context-dependent, particularly with respect to social environment. Together, these results demonstrate that early-life social environment plays a key role in shaping cuticular chemistry, reproductive physiology, and behavior, and highlights the importance of social context in shaping chemical phenotypes in social insects.