Infanticide effects on behavior of the bank vole (Myodes glareolus) in the fragmented breeding habitat

Abstract

Habitat fragmentation affects individual movements between favorable resource patches. In many small mammal species, an important intrinsic factor affecting recruitment of young is infanticide, committed especially by males. We predict that habitat fragmentation hinders movements of males between patches due to predation risk in the open areas. Thus, fragmentation reduces the number of males to which young litters are exposed to and decreases risk of infanticide in isolated habitat patches. Nonfragmented habitat provides not only breeding possibilities for more females but also safe movements to mate or commit infanticide for males. In a replicated enclosure experiment, we tested how infanticidal status of male bank voles (Myodes glareolus) affects their movements in fragmented vs. nonfragmented habitats with same total area and how this affects female spacing and offspring recruitment into population. We found no difference in the number of offspring recruited per female between infanticidal and fragmentation treatments. Females in the fragmented enclosures had smaller movement areas and stayed closer to their nests, suggesting better protection of pups against intruders. Infanticidal males moved more in general but especially in fragmented enclosures, whilst noninfanticidal males were moving more in nonfragmented enclosures. Our results suggest that behavior of females is affected by the habitat fragmentation, as we expected, but males searching for mates move similarly in safe and risky habitats. Thus, the threat of infanticide was not reflected in the recruitment of young into the population as probably the male–female interactions and effective nest protection by the mothers remained similar in both habitats.