Meeting Abstract
Ants are one of the few organisms that exhibit efficient social behavior involving a division of labor among nestmates. Pheidole dentata worker task performance patterns are variable. As in most ants, young workers are usually found in the nest caring for brood and sharing food, transitioning to riskier outside-nest tasks like foraging and defending the nest when they are older and physiologically mature. This flexible process of behavioral maturation is known to be affected by environmental factors like colony demography and task demand, as well as innate physiological mechanisms such as maturation of neuromodulatory biogenic amine systems in the brain. It has been suggested that injured ants could maximize colony fitness by assisting with dangerous tasks earlier than normal, similar to the behavior of older, uninjured ants. The physiological basis of this phenomenon has never been investigated. By injuring some ants by amputating an antenna or hind leg and comparing them to control ants of the same age, we observed differences in aggression level and propensity to leave the nest between each group. After being lesioned on the day of eclosion, ants were more likely to be outside of the nest 13, 14, and 15 days later when compared with same-aged control ants. Injured ants were also more aggressive in encounters with dead non-nestmate workers (competitors) and live fruit flies (prey items). Lastly, injured workers had increased brain biogenic amine levels. Since aminergic signalling has been shown to affect behavioral maturation in social insects, these changes could be causally related to the observed behavioral differences. Our study supports the growing consensus that physiological and environmental influences interact to influence worker task performance in insect societies.
