Activity Patterns and Age-dependent Changes in Behavior in the Clonal Ant Platythyrea punctata

Age-based polyethism, wherein young individuals perform tasks within the nest and later transition to outside activities, is common among many social insects. This division of labor ensures the safety of workers with longer residual lifespans, such as brood caring nurses, and exposes only old individuals to increased extrinsic mortality risks. It appears however, that lifespan in workers is also shaped by intrinsic factors, such as senescence. The transition from nurse to forager is accompanied by various physiological and behavioral changes and seems to represent a crucial step in determining the subsequent life history of the individual. Here we investigate the daily activity pattern and detailed division of labor in colonies of the clonal ant Platythyrea punctata to better understand the dynamics of age polyethism in this peculiar species. We found that P. punctata colonies were mostly active during the day. At night, few workers were observed out of their nests. Workers showed a decrease in brood care and aggressive behavior over time. With increasing age individuals spent more time outside the nest and were more frequently observed walking. However, the transition to outside tasks did not follow a consistent time pattern in all colonies. Workers transitioning at a younger age seemed to die earlier than workers that began to forage later in life.