Optimal diet models and rodent food consumption

Abstract

Generalizations derived from simple optimal diet models were field-tested at forest feeding stations where a choice of two foods was offered. The relationship between food availability and consumption by three species of rodents ( Peromyscus maniculatus, Clethrionomys gapperi and Napaeozapus insignis) was examined in five separate experiments. In all five cases rodents preferred the food which yielded the highest caloric gain per unit handling time, as predicted by the simple models. However, in all five cases, less preferred items were sampled even when they were not part of the optimal diet. In three cases the consumption of the non-preferred food type varied with its abundance and in one case food preference changed with its availability. The latter three results indicate that these rodents do not use simple optimal diet strategies.