Influence of female cuticular hydrocarbon (CHC) profile on male courtship behavior in two hybridizing field crickets Gryllus firmus and Gryllus pennsylvanicus.

Background : The hybridizing field crickets, Gryllus firmus and Gryllus pennsylvanicus have several barriers that prevent gene flow between species. The behavioral pre-zygotic mating barrier, where males court conspecifics more intensely than heterospecifics, is important because by acting earlier in the life cycle it has the potential to prevent a larger fraction of hybridization. The mechanism behind such male mate preference is unknown. Here we investigate if the female cuticular hydrocarbon (CHC) profile could be the signal behind male courtship. Results : While males of the two species display nearly identical CHC profiles, females have different, albeit overlapping profiles and some females (between 15-45%) of both species display a male-like profile distinct from profiles of typical females. We classified CHC females profile into three categories: G. firmus -like (F; including mainly G. firmus females), G. pennsylvanicus -like (P; including mainly G. pennsylvanicus ...