Prey chain transfer behaviour in the African stink ant, Pachycondyla tarsata Fabr.

Summary:

Pachycondyla tarsata workers display individual searching and hunting activities. Small groups of isolated individuals act as "patrollers", searching for food in the foraging territories around the nests. Finder ants returning laden with prey to the nest can transfer them to unladen nestmates if they are encountered. A prey can be transferred several times, even within the nest, before it finally reaches a nest chamber. In a series of experiments on this prey chain transfer behaviour (PCTB), prey were exchanged in half of the encounters. After prey retrieval, ants involved in PCTB returned preferentially to prey discovery or transfer areas, according to their role in the previous transport chain. The different tasks of PCTB seem to be interchangeable among individuals in the colonies, although ants from inside the nest have a stronger tendency to remain inside while outside ants do the opposite. Contacts between nestmates without transfer also encourage P. tarsata workers to forage, because they increase the number or the activity level of ants engaged in foraging labors, through the outbreak of an indirect recruitment process. It is hypothesized that PCTB works as a transport chain that ensures the quick retrieval of prey, enabling searching and hunting activities to continue simultaneously.