Barriers to Gene Exchange Between Closely Related Cricket Species. I. Laboratory Hybridization Studies
Harrison RG. 1983. Barriers to Gene Exchange Between Closely Related Cricket Species. I. Laboratory Hybridization Studies. Evolution. 37(2):245-251
SUMMARY: The field crickets Gryllus pennsyluanicus and Gryllus firmus hybridize and/or overlap in a narrow zone that stretches from the Blue Ridge Mountains in Virginia to southern Connecticut. This paper examines post-mating barriers to gene exchange between the two cricket species. Field-collected crickets from two sets of paired localities were used in laboratory hybridization studies. The paired localities represent G. pennsylvanicus and G. firmus populations adjacent to the zone of hybridization/overlap. Crosses between G. pennsylvanicus males and G. firmus females consistently failed to produce offspring. In contrast, the reciprocal cross resulted in viable and fertile F 1 hybrids. The outcome was not dependent on the locality from which the parents were obtained. Observations of spermatophore transfer demonstrated that the failure of the G. pennsylvanicus male X G. firmus female cross was indeed the result of a post-mating barrier. I evaluate the significance of these results for understanding both the origin of the hybrid zone and current patterns of gene exchange. I also consider possible explanations for the asymmetry in the outcome of the two reciprocal interspecific crosses.
- Type
- Journal Article
- Authors
- Harrison, Richard
- Units
- BLRI
- Keywords
- APHN, Appalachian Highlands Network, BLRI, Blue Ridge Parkway, field cricket, gene flow, Gryllus firmus, Gryllus pennsylvanicus, hybridization, Insecta, Orthoptera, SER, Southeast Region