Data from: Competitive behavior in house mice

Background: House mice are commensal animals with a nearly global
distribution, structured into well-differentiated local populations.
Besides genetic differences between the populations, they have also
diverged behaviorally over time, whereby it remains open how fast general
behavioral characteristics can change. Here we study the competitive
potential of two very recently separated populations of the Western house
mouse (Mus musculus domesticus) by using two different approaches – one
under controlled cage conditions, the other under more natural conditions
in enclosures mimicking a secondary encounter condition. Results: We
observe a clear bias in the competitive ability towards one of the
populations for both tests. The measured behavioral bias is also reflected
in the number of hybrid offspring produced in the enclosures. Conclusion:
Our data suggest that key behavioral characteristics with a direct
influence on relative fitness can quickly change during the evolution of
populations. It seems possible that the colonization situation in Western
Europe, with a rapid spread of the mice after their arrival, would have
favored more competitive populations on the expansion front. The study
shows the possible impact of behavioral changes on the evolution of
populations.