Divergence of mate recognition in the African striped mouse (Rhabdomys)

Abstract

Mate recognition systems (MRSs) are complex signal-receiver traits. The present study addressed the roles of phylogeny, ecology, and geography in shaping the MRS of the African striped mouse (<it>Rhabdomys</it>), which has a wide distribution in southern Africa. Two putative species are recognized, which have different ecologies: <it>Rhabdomys pumilio</it> (arid) and <it>Rhabdomys dilectus</it> (mesic). The latter may be further subdivided into 2 subspecies (<it>R. dilectus dilectus</it> and <it>R. dilectus chakae</it>). Using 2 discrete populations per taxon, we investigated within- and between-taxon variations in male odor quality and female perception using habituation-discrimination and habituation-generalization tests, and female preference in 2-way choice tests. Our results indicate: 1) no within-taxon variation in odor quality, perception, or preference; 2) the 2 subspecies of <it>R. dilectus</it> carry signals of different qualities but share a common odor characteristic distinct from that of <it>R. pumilio</it>; 3) female <it>R. pumilio</it> did not show a preference when their own species and <it>R. d. chakae</it> odors were presented simultaneously but displayed assortative preference when the alternative was <it>R. d. dilectus</it>; 4) females of the 2 subspecies showed dissimilar preferences: <it>R. d. chakae</it> for the genetically more similar taxon and <it>R. d. dilectus</it> for the most different one. Although we could not rule out the influence of ecology, we concluded that phylogeny appeared a more parsimonious explanation for the pattern of divergence in <it>Rhabdomys</it>. Further, we discuss our results in light of current models on signal-receiver coevolution.