Foraging for Work and Age-Based Polyethism: The Roles of Age and Previous Experience on Task Choice in Ants

In social insects, colonies commonly show temporal polyethism in worker behavior, such that a worker follows a predictable pattern of changes between tasks as it ages. This pattern usually leads from workers first doing a safe task like brood care, to ending their lives doing the most dangerous tasks like foraging. Two mechanisms could potentially underlie this pattern: (1) age‐based task allocation, where the aging process itself predisposes workers to switch to more dangerous tasks; and (2) foraging for work, where ants switch to tasks that need doing from tasks which have too many associated workers. We tested the relative influence of these mechanisms by establishing nests of Camponotus floridanus with predetermined combinations of workers of known age and previous task specialization. The results supported both mechanisms. Nests composed of entirely brood‐tending workers had the oldest workers preferentially switching to foraging. However, in nests initially composed entirely of foragers, the final distribution of tenders and foragers was not different from random task‐switching and therefore supportive of foraging for work. Thus, it appears that in C. floridanus there is directionality to the mechanisms of task allocation. Switching to more dangerous tasks is age‐influenced, but switching to less dangerous tasks is age‐independent. The results also suggest that older workers are more flexible in their task choice behavior. Younger workers are more biased towards choosing within‐nest tasks. Finally, there are effects of previous experience that tend to keep ants in familiar tasks. Task allocation based on several mechanisms may balance between: (1) concentrating the most worn workers into the most dangerous tasks; (2) increasing task performance levels; and (3) maintaining behavioral flexibility to respond to demographic perturbations. The degree to which behavior is flexible may correlate to the frequency of such perturbations in a species.