Cross-fostering by foreign conspecific queens and slave-making workers influences individual- and colony-level personality

Abstract

Recent studies of inter-individual variation in behavior have focused primarily on its environmental causation and adaptive consequences, but commonly ignore questions regarding its proximate development. Here, we explore the effects of the late natal environment on the development of individual- and colony-level personalities in the acorn ant, Temnothorax longispinosus. This species is commonly parasitized by the slave-making ant Protomognathus americanus, and we predicted that rearing T. longispinosus with its brood parasite would alter the behavior of individual ants and the collective, colony-level personality of groups. Using a split-brood design (where brood from a single source colony is split equally across different rearing environments), we reared T. longispinosus in four conditions: their maternal queen, an unrelated conspecific queen, a slave-making queen, and a slave-making worker. Although individual aggressiveness and exploratory behavior did not differ between ants raised by their maternal queen or slave-making ants, ants raised by an unrelated conspecific queen showed increased aggressiveness 60 days after emergence. Further, groups of ants raised by slave-making workers were faster at locating new nest sites, a collective behavior, relative to groups reared by their maternal queen. Lastly, colonies containing T. longispinosus and their maternal queen had the greatest brood production at 60 days. Our results demonstrate that differences in individuals’ rearing environment can influence both individual- and colony-level personality in multi-level societies.