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

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 (Rhabdomys), which has a wide distribution in southern Africa. Two putative species are recognized, which have different ecologies: Rhabdomys pumilio (arid) and Rhabdomys dilectus (mesic). The latter may be further subdivided into 2 subspecies (R. dilectus dilectus and R. dilectus chakae). 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 R. dilectus carry signals of different qualities but share a common odor characteristic distinct from that of R. pumilio; 3) female R. pumilio did not show a preference when their own species and R. d. chakae odors were presented simultaneously but displayed assortative preference when the alternative was R. d. dilectus; 4) females of the 2 subspecies showed dissimilar preferences: R. d. chakae for the genetically more similar taxon and R. d. dilectus 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 Rhabdomys. Further, we discuss our results in light of current models on signal-receiver coevolution. Copyright 2006.