FOOD PREFERENCES OF VOLES RELATED TO POST-WEANING NUTRITION

Rodents can be grouped according to nutritive strategies in an array from pronounced granivores to pronounced folivores. The food choice is related to adaptations in digestive morphology and physiology, e.g. in intestinal size. A hypothesis that early food conditions affect food preferences was tested by examining food selection in animals that were given more and less coarse food for various periods. Wild animals taken from more and less fluctuating populations, and thus with different natural food supply, were also compared with regard to food selection. Pronounced differences between wild-caught and laboratory-bred animals indicated that effects on digestive physiology and food preferences occurred shortly after weaning. Coarser food at that time caused an increased interest in tree bark but also an increase in general storing behaviour. There was no trade-off between seed and bark selection as might have been expected from the alternative diet specializations. The interest in bark food increased in wild-caught but laboratory-acclimated animals according to the population phase in the original populations, indicating varying nutritive conditions during the post-weaning periods.