Can alternative mating tactics facilitate introgression across a hybrid zone by circumventing female choice?

Reproductive barriers and divergence in species’ mate recognition systems underlie major models of speciation. However, hybridization between divergent species is common, and classic mechanisms to explain permeable reproductive barriers rarely consider how an individual may attain reproductive success. Alternative mating tactics exist in various forms across animal taxa. Such tactics may allow poorer quality individuals to gain mating opportunities and facilitate introgression either through asymmetrical positive selection, or by circumventing female choice altogether in areas of secondary contact. One such tactic is satellite behaviour in frogs, where silent males perch near advertisers in an attempt to intercept females. To test whether such satellite male tactics are context-dependent and favoured by hybrids, we genotyped and quantified the morphology of 80 male spring peeper (Pseudacris crucifer) individuals involved in caller-satellite associations from a secondary contact zone bet...