Barriers to gene exchange between closely related cricket species. II. Life cycle variation and temporal isolation.

Abstract

The closely related field crickets Gryllus firmus and G. pennsylvanicus hybridize in a zone of contact that extends over >800 km from the Blue Ridge in Virginia to S Connecticut. The extent of temporal reproductive isolation of the 2 cricket species varies along the length of the zone. Although G. firmus and G. pennsylvanicus are temporally isolated in Virginia, adults of the species do occur together. Examination of Esterase genotypes of field-inseminated females and their progeny from a mixed population on the Blue Ridge suggests that premating barriers other than temporal isolation are not effective in preventing gene exchange.-from Author