Hunting efficacy of workers from incipient colonies in the myrmicine ant Myrmicaria opaciventris (Formicidae : Myrmicinae)

We studied the predatory behavior of Myrmicaria opaciventris workers in thr ee situations: (A) foraging workers from mature colonies under natural cond itions; (B) young workers from parts of mature colonies in a situation of s ocial regulation; and (C) young workers from incipient colonies. Termite wo rkers, Microcerotermes fuscotibialis and Macrotermes bellicosus, were used as small and medium-sized prey, respectively, and grasshopper larvae as lar ge prey. Differences in prey capture concerned detection (from a distance o r by contact), with experienced workers from group A detecting termites by contact, while workers from both groups B and C detected them from a distan ce. Grasshoppers were detected from a distance in all cases. Small prey wer e captured and retrieved solitarily by all kinds of workers. Large and medi um-sized prey were captured either solitarily or in groups by workers from both groups B and C; and always solitarily by those from group A. The latte r, serving as reference, were always more successful than those fi-om both other groups. Workers from incipient colonies (C) were never handicapped by their small size as they were as successful as those from social regulatio n colonies (B) during termite capture and even more successful during grass hopper capture. We conclude that workers from incipient colonies are well a dapted to successfully provisioning the colonies by hunting when the queens ' reserves are lacking.