Tracking the origin of the smearing behavior in long-nosed bats (Leptonycteris spp.)

A unique and novel stereotypic 'smearing' behavior and the formation of an odoriferous dorsal patch have been recently described in two species of long-nosed bats, Leptonycteris curasoae and L. yerbabuenae (Glossophaginae: Phyllostomidae). It has been hypothesized that this structure represents a mechanism involved in female mate choice mediated through odor, and that it has only evolved within the genus Leptonycteris. No evidence has been published indicating whether the smearing behavior and the dorsal patch occur in L. nivalis, the third extant species within the genus. We reviewed the available data on the mating behavior of L. nivalis and conducted four surveys on the only mating colony known for this species at Cueva del Diablo, Tepoztlan, Morelos, Mexico, searching for evidence of both the smearing behavior and the dorsal patch in reproductive males of this species. Our findings indicate that L. nivalis does not display the smearing behavior or the dorsal patch, suggesting that this trait and its role in mate choice by females must have evolved from a common ancestor of L. yerbabuenae and L. curasoae after it separated from L. nivalis, between 1.0 and 0.5 million years ago. We propose a possible hypothetical scenario for the evolution of the smearing behavior, based on differential levels of ectoparasitic pressure acting on bat populations established at locations with markedly different environmental temperatures.