Can scent-mediated female mate preference explain an abrupt mtDNA cline in Lacerta schreiberi?

Divergence in female mate preferences can strongly influence the structure and dynamics of hybrid zones. We examined the potential role of female mate preferences in maintaining an abrupt west-east mtDNA cline between two deeply divergent genetic lineages of Lacerta schreiberi, a lizard endemic to the Iberian Peninsula. The lineages are largely morphologically cryptic but with respect to the mtDNA cline, western males tend to be less parasitized, in better body condition and more intensely coloured than eastern males, a pattern that cannot be explained by environmental variation alone. The lineages may also differ in unmeasured aspects such as physiology, behaviour and olfactory signals, which may influence mate choice. As female mate attraction has been found to vary with olfactory cues in lacertid lizards, we experimentally tested whether females were differentially attracted to femoral pore secretions of males from the two genetic backgrounds. Females did not prefer scents of 'higher quality' western males, nor did they prefer the scents of males belonging to their own genetic background. This suggests the abrupt mtDNA cline is unlikely to be explained by assortative mating of matrilineages that distinguish male genetic background based on scent.