Olfactory preferences in two strains of wild mice, Mus musculus musculus and Mus musculus domesticus, and their hybrids

We studied olfactory preferences of two strains of mice, Mus musculus musculus and Mus musculus domesticus (considered here to be subspecies), and their hybrids, to examine the possible role of odours as a behavioural, premating mechanism that could explain the characteristics of their natural hybrid zone. We used a choice test with the bedding material of animals of the opposite sex from the animal tested and from both subspecies. Male and. female M. m. domesticus showed no preference either for their own subspecies' odours or for the other subspecies' odours. In contrast, M. m. musculus individuals and three types of hybrids (all the female hybrids and males from crosses between an M. m. musculus female and an M. m. domesticus male) sniffed for longer at materials from the musculus source than from the domesticus source. We interpreted the results asa preference for musculus odours. Differences between the two subspecies in their response towards consubspecific and heterosubspecific odours could explain the asymmetrical introgression observed in the hybrid zone. (C) 1998 The Association for the Study of Animal Behaviour.