Analysis of behavioural discrimination mechanisms in a contact zone between two metacentric races of the house mouse,Mus musculus domesticus, in central ItalyAnalisi dei meccanismi comportamentali di discriminazione in una zona di contatto tra due razze metacentriche del topolino domestico, Mus musculus domesticus,in Italia Centrale

We characterised the behavioural regimes of two chromosomal races ofMus musculus domesticus (ACR 2n=24 and CD 2n=22) in an area of parapatric contact in central Italy in order to check for behavioural differences related to race-specific mate recognition. The investigation involved the analysis of olfactory preferences and behavioural acts in dyadic encounters. The results demonstrate that mice from this contact zone do not show clearly different responses when subjected to olfactory stimuli belonging to their own race or to the other race. Analysis of the dyadic encounters indicates that ACR males have more sexual attention towards CD females than towards females of their own race. Moreover, the ACR males are more aggressive towards the CD males. We discuss these results in terms of a scenario explaining the reproductive isolation observed in the field.