北美田鼠亚科啮齿动物营养生态学研究进展

PROGRESS IN THE STUDIES ON THE NUTRITIONAL ECOLOGY OF MICROTINE RODENTS IN NORTH AMERICA

This paper introduced progresses in the studies on the nutritional ecology of micro-tine rodents in north America, and mainly reviewed the dietary pattern, food selection, nutrient requirement, forage quality and the role of nutrition in population dynamics for the microtines. Several characteristics of the molars and the gastro-intestinal tracts of microtine rodents appear to be adaptations for use of high-fiber , low-protein , and low-mineral diets, which are consistent with the observation that most microtine species eat primarily the vegetative parts of plants. The exact compositions of diets are a function of the availability of food items and the nutritional adaptations of thespecies; the most accurate estimates of diet composition for microtine rodents seem to be volumetric estimates based upon microscopic exmination of stomach contents. The same species in different habitats and different species in the same habitat eat different food items. Food item preference seems to depend upon a combination of the positive and negative characteristics of the item , and different speeies have different tolerance for different plant secondary compounds.Performances of the microtine rodents on particular food items parallel their food preferences as measured by food intake and body growth. The nutrient requirements of the microtine rodents seem to require lower concentrations of digestible energy and protein in their diets. Mineral requirements are similar to laboratory rodents. Increased intake can compensate for the food of low digestibility and nutrient content so that requirements for energy and nutrients are met.Some evidences indicate that the quality of available forage can explain differences in the densities of microtine populations on time and space.