Baby Killers: Documentation and Evolution of Scuttle Fly (Diptera: Phoridae) Parasitism of Ant (Hymenoptera: Formicidae) Brood.

Background: Numerous well-documented associations occur among species of scuttle flies (Diptera: Phoridae) and ants (Hymenoptera: Formicidae), but examples of brood parasitism are rare and the mechanisms of parasitism often remain unsubstantiated.

New Information: We present two video-documented examples of ant brood (larvae and pupae) parasitism by scuttle flies. In footage from Estação Biológica de Boracéia in Brazil, adult females of Borgmeier can be seen attacking workers of (Mayr) species group while they are carrying brood, and ovipositing directly onto brood in the nest. In another remarkable example, footage from the Soltis Center, near Peñas Blancas in Costa Rica, shows adult females of an unidentified species of the Borgmeier group mounting Westwood brood upside-down and ovipositing while the brood are being transported by workers. Analysis of evolutionary relationships (in preparation) among Coquillett species shows that this is a newly derived behavior within the genus, as the group arises within a group of adult ant parasitoids. In contrast, relationships of Borgmeier have not been studied, and the lifestyles of the other species in the genus are largely unknown.