A POPULATION STUDY OF HOUSE MICE (MUS MUSCULUS CASTANEUS) INHABITING RICE GRANARIES IN TAIWAN

Samples of house mice (Mus musculus castaneus) were collected from ric e granaries in 5 townships in Taiwan to study the population biology o f the species, including population dynamics, reproductive biology, se x ratio, and age structures. The population sizes among granaries were highly variable and this is assumed to result from changes of rice st orage. House mice can breed year round, as expected by the species com mensal habits. Two methods for age determination, i.e., tooth wear pat terns and body weight criteria, were established and compared. Age str ucture of the populations seemed to have remained stable as a result o f continuous breeding activities. Sex ratio of the populations were 1: 1, but fewer males were represented among old mice than among young mi ce. Finally, we report on high rates of tapeworm infection and missing teeth in these mouse populations.