Diet selection in rodents: An experimental test of the effect of dietary fiber and tannins on feeding behavior
Abstract
The individual effects of chemical plant defenses on food preferences in small mammals have been explored in many studies. However, the combined effects of dietary fiber and tannins on feeding preference have received considerably less attention. Here I search for differences in feeding behavior of alternative experimental diets differing in fiber (cellulose = F) and a secondary metabolite (the hydrolyzable tannin, tannic acid = TA) in two sympatric rodent species that live in the Mediterranean environments of central Chile. I used the herbivorous burrowing caviomorph rodent Octodon degus (specialist), and the granivorous Sigmodontine Phyllotis darwini (generalist). These species differ in their trophic niche, and likely in behavioral and physiological features to cope with plant defenses. In preference trials with isocaloric diets, both species prefered dietary items with low F and TA. I conclude that non-energetic dietary features influence feeding strategies, and that generalist and specialist species behave in the same way. Future studies dealing with the ecology of foraging on chemical plant defenses should focus more explicitly on the interactive effect of different plant defensive compounds instead of on the isolated effect of single factors.
Description
Keywords
feeding behavior, fiber, tannin, rodents