Variation in individual worker honey bee behavior shows hallmarks of personality

The existence of personalities has been explored in various invertebrates, but a comprehensive investigation of personality differences across individuals in a eusocial insect has not yet been conducted. The study of personality differences across individuals within the same behavioral caste may contribute to an understanding of how social insects divide labor within the nest. Here, we define and investigate three dimensions of personality within the worker caste of a model social insect, the honey bee Apis mellifera, as follows: (1) consistent individual behavioral differences over time, (2) consistent individual behavioral differences across contexts, and (3) the presence of correlated suites of behaviors. To test whether honey bee workers exhibit dimensions 1 and 2, we repeatedly assessed responses of groups of same-age bees in cages to stimuli that are relevant to bee life history. To test for dimension 3, we examined behavior within a colony context by using observation hives to record the behaviors of individual bees across their lifetimes. Our results provide some evidence for all three dimensions of personality in honey bee workers. In particular, our data suggest some individuals may be more likely to be highly interactive with other workers (e.g., engaging in food sharing), while other individuals are consistently less interactive. These findings expand upon and contribute to previous models for the organization of worker division of labor in honey bees, suggesting that consistent behavioral differences (personalities) of workers within a behavioral caste have the potential to contribute to subcaste division of labor. Significance statement Behavioral ecologists have become increasingly interested in animal personalities, individual behavioral differences that are consistent over time and in different contexts, with recent focus on understanding the occurrence of personalities across taxa and their adaptive value. The existence and function of personality differences among individuals in complex societies, such as eusocial insects, remain understudied. Here, we provide the first comprehensive investigation of whether workers of the highly eusocial honey bee show hallmarks of personality. Although these workers demonstrate well-documented behavioral changes as they age, we uncovered some aspects of their behavior, in particular, their tendency to physically interact with other bees, remain somewhat consistent even as they age and change roles within the colony. We suggest that individual-level personality differences have the potential to contribute to colony division of labor by creating variation in individual tendencies to perform different tasks.