Branch-cutting behavior by the vole (Microtus pennsylvanicus) : A mechanism to decrease toxicity of secondary metabolites in conifers.

While investigating the preferences of meadow voles (Microtus pennsylvanicus) toward various coniferous species, we noted they often cut the branches of young trees, and then left them lying on the snow for two days or more before eating them completely. We tested whether this "behavioral manipulation" of a potential food resource resulted in a decrease in the level of secondary metabolites in branches. We found that after being cut for more than three days, the branches of young conifers had significantly less phenolics and condensed tannins. These postmanipulation levels of secondary metabolites were similar to those found in preferred summer food resources. Voles were thus capable of transforming a low-quality resource into one that was more compatible with their feeding patterns and detoxification mechanisms.