FEMALE AGGRESSION IN MICROTUS-PENNSYLVANICUS - ARENA TRIALS IN THE FIELD

The relative importance of site- and individual-specific aggression be tween resident and nonresident adult female Microtus pennsylvanicus wa s investigated using encounter trials in the field. Residents within t heir home range exhibited significantly greater aggression when paired with nonresident females and a trend towards greater aggression when paired with resident females that were removed from their home range. Nonresident females exhibited significantly more aggression than resid ents when the trial was conducted at a neutral site. These results sug gested a dual basis for female aggression with evidence for both site- and individual-specificity.