Is space management of female meadow voles (Microtus pennsylvanicus) related to nutritive quality of plants?

It is thought by many (see Ims 1987 for review; Desy and Batzli 1989) that high quality food regulate population processes, territoriality and mating systems among small herbivores like meadow voles (Microtus pennsylvanicus). We thought that comparisons of nutritive components from selected plants eaten by sexually active and inactive voles, as well as between territorial and non territorial sexually active females would bring some light into these theoretical considerations. Sexually active females did have a higher diet quality over inactive ones and over active and inactive males. Nutritive components of selected species from territorial reproductive females did not vary significantly from those of the non territorial females the year of higher crowding conditions but they varied significantly the following year when population density of voles was much lower. This decline in food quality coincided with a switch in food selection. Since there were only eight plant species involved in such processes, we think that crowding condition and availability of high quality food are two factors involved concurrently in space management and territoriality among voles.