Revista de la Sociedad Entomológica Argentina (Dec 2005)
Rasgos morfológicos asociados a la viabilidad de pupas en parasitoides del género Pseudacteon (Diptera: Phoridae) Morphological traits associated with pupae viability in Pseudacteon (Diptera: Phoridae) parasitoids
Abstract
RESUMEN. Fóridos del género Pseudacteon Coquillett oviponen en forrajeras del género Solenopsis Westwood y empupan en sus cabezas. Se evaluó la relación entre la viabilidad de los parasitoides, la presencia de cuernos respiratorios y el color en los opérculos de los puparios de cuatro especies de Pseudacteon criados sobre Solenopsis invicta Buren y Solenopsis richteri Forel. La presencia de cuernos respiratorios estuvo asociada a la viabilidad de las pupas para las especies consideradas (p 0,09); excepto cuando Pseudacteon cultellatus Borgmeier se desarrolló sobre hormigas de la reserva y niñeras de S. invicta (p ABSTRACT. Pseudacteon Coquillett phorid flies oviposit on Solenopsis Westwood ants and pupate within the ant's head. We have evaluated the relationship between pupae's viability, presence of respiratory horns and the operculum color in four species of Pseudacteon reared on Solenopsis invicta Buren and Solenopsis richteri Forel ants. The presence of respiratory horns was significantly associated with pupae's viability for all species considered (p 0,09), except (p < 0,01) when Pseudacteon cultellatus Borgmeier had developed on S. invicta nanitic and reserve workers. Pupae with light-colored opercula were more frequent in P. cultellatus, whereas brown opercula were more frequent for the other species that attack bigger ants. Mimetism can be invoked to explain the similarity in opercula color with that of the head of the parasitized ant as a way to avoid recognition by members of the colony. We conclude that the presence of respiratory horns is necessary for pupae survival of most of the pupae and we suggest to use the presence of respiratory horns as an indicator of the efficiency of rearing protocols for this group of parasitoids. We also recommend using forager ants because other casts do not seem to be appropriate hosts.
