Biological attributes of Argentinian phorid parasitoids (Insecta: Diptera: Phoridae) of leaf-cutting ants, Acromyrmex and Atta

Little is known about the natural history of phorid parasitoids of leaf-cutting ants, an important pest in the Neotropics. This is particularly so for phorids attacking Acromyrmex species. We searched for phorids ovipositing and reared them from ants collected in the field. We found that these phorids formed a guild. Acromyrmex phorids selected ants from all sizes available outside the nests, whereas Atta phorids did not parasitize the smallest workers and soldiers. Maximum parasitism by phorids was 12% for Acromyrmex and 35% for Atta hosts, percentages higher than any reported previously. Some phorid species coexisting in a site showed differences in developmental times. Only 1.1% of phorids collected over hosts were males; however, as the male : female ratios from parasitoid rearing did not differ from one, mating is suspected to occur elsewhere. Our results helped to increase the knowledge of the phorids of leaf-cutters, and highlighted their potential use for the biocontrol of these ants.