Rescue specialists in Cataglyphis piliscapa ants: The nature and development of ant first responders

Previous research in our laboratories has demonstrated that, within each colony of Cataglyphis piliscapa (formerly C. cursor) ants, only some individuals are capable of performing a complex sequence of behavioral patterns to free trapped nestmates-a sequence that not only is memory-dependent but also is responsive to the particular circumstances of that entrapment and how the rescue operation unfolds. Additionally, this rescue behavior is inherited patrilineally from but a few of the many males that fertilize the eggs of the colony's single queen. Here, we describe three experiments to explore rescue behavior further-namely, whether rescuers are in any way selective about which nestmates they help, how the age of rescuers and the victims that they help affect the quantity and quality of the rescue operation, and when this complex behavior first emerges in an ant's development. Taken together with the previous heritability analysis, these behavioral experiments provide clear evidence that the ability to rescue nestmates in distress should be recognized as a specialization, which together with other specialized tasks in C. piliscapa, contributes to a division of labor that increases the efficiency of the colony as a whole and, thus increases its reproductive success.