Mating Behaviour and Female Mate Choice in the Harvest Mouse

Though fairly common in the English countryside, and with a range reaching all the way to Japan, the harvest mouse  Micromys minutus is still an understudied animal. Rising concerns over its conservational status stresses the need to study various aspects of this species life. This study focuses on its mating behaviour and female mate choice.

Understanding the mating system of a species is crucial for the understanding of the species as a whole, especially when conservation attempts are involved. It is important when conducting captive breeding programs (as is already being done in harvest mice) or while studying a wild population, where the effective population size affects the species continued survival at a certain location. Studying the mating systems of a species can also provide a better understanding of its social interactions in a more general way, with different female preferences being linked to different social structures. So while studying harvest mice social interactions in the field is extremely difficult (due to its small size and mostly solitary life), learning more about their mating system in captivity could provide us with clues as to their social structure in natural conditions.

The study includes two sets of experiments in which a female is presented with two males, one familiar to her and one not.

1)    A more controlled experiment, where the female is free to move around the entire experimental arena and the males are confined to their own chamber. This allows studying female mate choice without the confounding effects of male-male competition.

2)    In more natural conditions, where all three individuals are free to move around. This setup allows the males to interact with each other, thus potentially influencing the female's choice.

Familiarity was chosen as the differing characteristic as it has been shown to be a factor in a female's choice of mate in many species. This choice is usually connected to the species social structure, so that species where females prefer to mate with unfamiliar males tend to be social (and this preference is – amongst other things – connected to in-breading avoidance) and a preference for a familiar male is more common in solitary species, where such a familiarity would be associated with a neighbouring male, rather than a relative.