Developmental isolation and subsequent adult behavior of Drosophila paulistorum.: V.: Survey of six sibling species

In an investigation into the effects of developmental isolation from all conspecifics, the Drosophila willistoni group of six sibling species responded to differing degrees: all six are reproductively isolated from D, paulistorum, the tester species. Drosophila pavlovskiana, a narrow endemic, proved the most vulnerable, responding by reducing its adult sexual isolation, if eggs, any instar, and sometimes even pupae were socially isolated. To lesser degrees, D. tropicalis and D. willistoni both produced similar results only when their eggs were isolated, i.e., when from the moment of egg deposition on, there was absolutely no contact with other flies until testing for mating behavior. The remaining siblings, D. equinoxialis and D. insularis, were immovable.