Facultative Mate Choice Drives Adaptive Hybridization
Karin S. Pfennig
Mating with another species (hybridization) is often maladaptive.
Consequently, females typically avoid heterospecifics as mates.
Contrary to these expectations, female spadefoot toads were
more likely to choose heterospecific males when exposed to environmental
conditions that favor hybridization. Indeed, those females with
phenotypic characteristics for which hybridization is most favorable
were most likely to switch from choosing conspecifics to heterospecifics.
Moreover, environmentally dependent mate choice has evolved
only in populations and species that risk engaging in, and can
potentially benefit from, hybridization. Thus, when the benefits
of mate choice vary, females may radically alter their mate
selection in response to their own phenotype and their environment,
even to the point of choosing males of other species.
