Malagasy Ant Pheidole longispinosa (Forel, 1891) Behavior as Regionally Dominant Ant Predator in Rainforest Environment (Hymenoptera: Formicidae)

Abstract

Workers from colonies of Pheidole longispinosa (Forel, 1891) in primary forests of Ranomafana National Park in the Fianarantsoa province of Madagascar engaged in periodical predatory raids against neighboring nests of rival ants, most prevalently Pheidole oswaldi (Forel, 1891) and Paraparatrechina glabra (Emery, 1914). Pheidole longispinosa workers engaged in sporadic “hit and run” attacks against foraging lines of enemy ants, preying upon workers as they returned to their respective nests, as well as organized raids on nest entrances. These raids also targeted wood dwelling termite nests. Behavioral observations were made over a 14-day period, with both daylight and nocturnal observations occurring. P. longispinosa was active only during the day, and preyed upon P. glabra regularly, with consistent raids of their foraging columns, and by surprising workers leaving nest entrances. Predation of P. oswaldi only occurred while defending from raids, or from carrying out raids of their own. Individual termites were attacked on sight, and their nest was sporadically raided. Data were taken on types and numbers of prey consumed by P. longispinosa. Behavioral observations of predation, aggression, and communication were also taken. Behaviors such as worker rescue and group hunting were observed. Detailed notes on worker activity were maintained over a 14-day period. P. longispinosa exhibited a local dominance of the invertebrate fauna in the area surrounding their nest. Throughout the observation periods, conflicts with neighboring P. oswaldi were commonplace, with P. longisposa carrying out raids, consuming workers of neighboring ant species.