Social Behavior in American Sweat Bees: A comparative analysis of conspecific interactions in the solitary Augochlora pura and the eusocial Augochlorella aurata

Abstract

The Halictidae (Sweat Bee) family contains some of the greatest variety of social behavior in insects across the globe, making it an excellent model clade for comparative behavioral research. This study aims to characterize social behavior differences between two closely related halictid species: the solitary Augochlora pura, and the facultatively eusocial Augochlorella aurata. It also looks at whether bees that are strangers behave differently than bees with previous smell familiarity with one another. My predictions going in were that these bees would exhibit different conspecific social behaviors, between both strangers and familiar individuals, with the solitary A. pura being more avoidant and aggressive overall, and the social A. aurata being more tolerant. Behavioral assays were conducted by observing bee interactions in Petri dishes. For the two treatment groups, bees were either placed directly into a petri dish together for a trial with no previous acquaintance, or bees were first placed together into a compartmented petri dish that allowed for gaseous exchange, to gain smell familiarity before their trial. The metrics measured were behavior frequencies and durations, and distance between the two bees. The results show that these two species do display different social patterns, with the social species being unexpectedly more spatially avoidant than the solitary species. Comparative studies of this kind can complement research in other fields, such as sociogenomics, by showing what specific social behavior variations can come as a result of genetic and physiological differences.