MOVEMENT OF MEADOW VOLES IN RESPONSE TO FOOD AND DENSITY MANIPULATIONS - A TEST OF THE FOOD-DEFENSE AND PUP-DEFENSE HYPOTHESES

The space-use patterns of female voles are believed widely to be drive n by food availability, whereas male voles respond primarily to availa bility of receptive females. Alternatively, female voles may maintain exclusive territories to prevent infanticide. We manipulated populatio n densities and levels of food availability in replicate populations o f the meadow vole, Microtus pennsylvanicus, to determine the impact of each on movement distances. Sex differences occurred in the responses of voles to food and density treatments. Adult male voles responded t o food supplementation by decreasing movement distances, irrespective of density. Adult female voles only contracted movement distances unde r high densities. Male voles may respond to changes in food availabili ty when female voles are dispersed widely and do not constitute a defe nsible resource. Female voles may retain fairly constant home ranges i n the face of increased food availability to prevent infanticide. Our data suggest that habitat characteristics are important in the spacing behavior of male voles and food abundance is not the primary determin ant of the spacing behavior of female voles.