Feeding strategy of two rodent species in a set-aside field and its influence on alimentary tract morphometry

摘要

We examined the feeding strategy of two dominant rodents, the common vole (Microtus arvalis) and the pygmy field mouse (Apodemus uralensis), in set-aside fields over a period of 1 year. Diet analysis revealed dominance of green plant shoots in common vole's diet and seeds in the diet of the pygmy field mouse. Food availability in the set-aside fields was strongly correlated with the diet of the herbivorous common vole, but not with that of the granivorous pygmy-field mouse. Both feeding strategies reflect specific morphological adaptations of the digestive tract of both species. A comparison of the gastrointestinal tract (GIT; length and mass without oesophagus; including contents) of the common vole and pygmy field mouse revealed a correlation between body size and length and the GIT weight in both species. The common vole had a proportionally heavier GIT with a larger of the common vole and pygmy field mouse relative proportion of caecum. The GIT length was proportionally greater in juvenile females, while the GIT weight was greater in adult females of both species. The GIT morphometry of both species varied with season and reproductive status, presumably as food consumed altered in line with vegetation phenology and the rodent's energy requirements.