FEMALE MATE PREFERENCE AND REPRODUCTIVE ISOLATION IN POPULATIONS OF THE STRIPED MOUSE RHABDOMYS PUMILIO

Laboratory experiments were conducted to study female mate preference in three allopatric populations of the striped mouse Rhabdomys pumilio, an African murid rodent. The three populations (Alice, Goegap, Irene) represent the extremes of the distribution range of the species in South Africa. Using two-way choice tests, virgin females were exposed to: (i) males of the same population (homotype) and those of another population (heterotype) in whole animal choice tests, or (ii) the odiferous bedding of homotype and heterotype males. Generally, females significantly preferred homotype stimulus males or their odour. This preference was only evident when females were in oestrus, suggesting that females were choosing potential mates. In addition, prior association with males is not needed for the establishment of female mate preference, since females were never exposed to adult males of any of the populations prior to testing. The only exception was receptive Goegap females which showed equal preference for homotype and Alice heterotype males. Mate preference in these two populations is asymmetric since Alice females showed strong preference for homotype males over Goegap males. The results indicate that divergence has occurred in allopatry, resulting in populationspecific communication signals and in particular olfactory cues, assortative mate choice, and pre-mating reproductive isolation.