Male flat lizards prefer females with novel scents

Abstract

In lizards, pheromonal cues are important for mate recognition and are expected to diverge during the speciation process. We tested for divergence in pheromonal mate and species recognition between male flat lizards (Platysaurus broadleyi) belonging to the same population, a different population, and a sister species. Males were given a choice between two refuges, an odourless control and one of the following: a conspecific female from the same population (sympatric), a conspecific female from a distant population (allopatric), and a female from their sister species  (heterospecific), P. capensis. Males chose refuges treated with the scent of a
heterospecific over an odourless control refuge but showed no preference for refuges that were scented with female conspecific (allopatric or sympatric) cues over the control. These results were consistent in the breeding and non-breeding seasons. In a second experiment males were offered a choice of female scents between  sympatric and allopatric conspecifics; an allopatric conspecific and a  heterospecific; and a sympatric conspecific and a heterospecific. Males showed a trend of preferring heterospecific over conspecific refuges and allopatric over sympatric conspecific-scented refuges, but these results were not significant at alpha <0.05. Contrary to our original expectations, these experiments do not provide any evidence for a pheromonal pre-mating isolation mechanism within this species complex. However, our results suggest a preference for novel female scents by males, consistent with selection for genetic diversity.

Key words: lizard, pheromones, novel mate preference.