Infanticide and Population Growth in the Bank Vole (Myodes glareolus): The Effect of Male Turnover and Density

One major intrinsic factor affecting recruitment of young into a population is infanticide, the killing of conspecific young by adult males. It occurs in most mammal species, like our study species the bank vole (Myodes glareolus), and is widely accepted as an adaptive behavior, which may increase male fitness via nutritional gain, decreased competition, or an increased access to mates. A turnover of males in a population increases the risk of infanticide owing to a disruption of social structures. In a controlled field study, we tested the effects of total male turnover and density on juvenile recruitment and female space use in experimental bank vole populations. Juvenile recruitment declined significantly in low-density populations with male turnover, while growth of high-density populations seemed unaffected. The females spatial behavior seemed unaffected by both male turnover and density. Our results suggest that male infanticide may considerably affect population growth and it is more likely to do so at lower densities.