DISRUPTION OF THE STRUCTURE OF LARVAL FORAGING BEHAVIOR IN INTERSPECIFIC HYBRIDS IN DROSOPHILA

Larval foraging behaviour in two sibling species, Drosophila pavani an d Drosophila gaucha belonging to the mesophragmatica species group, is described. Interspecific hybrid larvae derived from both reciprocal c rosses of the parent species show disruption in the organization of th eir behaviour, leading to lower mean feeding rates. This, together wit h interactions involving biotic residues, described elsewhere, is like ly under competitive conditions to contribute to reduced fitness of th e hybrids relative to the parent species.