FEEDING DIVERSITY IN DEER MICE

Compared the foraging behavior of 2 geographically isolated subspecies of deer mice. Laboratory-reared Peromyscus maniculatus borealis from the prairies of Alberta, Canada and P. m. blandus from the deserts of Arizona were studied in 3 tests emphasizing different aspects of foraging: approach, acquisition, and consumption. Two measures were used to compare feeding: diversity, an index of the breadth of the diet, and preference, an index of what Ss ate most. A consistent difference found between the 2 subspecies in individuals' feeding diversity suggests that this subspecific effect is due to genetic differences, as predicted by evolutionary theory. At the same time that individuals of each subspecies had roughly the same diversity, they had different preferences, which suggests that they are more variable or opportunistic in their foraging choices than predicted by theories of optimal foraging. (38 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1979 American Psychological Association.