Natal philopatry in the prairie vole, Microtus ochrogaster, in a low food habitat.

INTRODUCTION

Social organization of the prairie vole, Microtus ochrogaster, consists of communal groups formed primarily by addition of philopatric offspring to male-female pairs (Getz, et al., 1993). It has been proposed that prairie vole male-female pairs and communal groups evolved as an adaptation to a low-food habitat (Getz et al., 1992, 1993). In their "benefits of philopatry hypothesis" Stacey and Ligon (1987) predicted natal philopatry and communal nesting in birds and mammals to be adaptations to high-food habitats. These authors proposed that where food is abundant, offspring would have sufficient resources to be successful in rearing their own offspring while remaining within the natal home range. Such philopatric offspring would also avoid the risks of mortality associated with dispersing through unfamiliar sites in search of a suitable home range. Thus, there would be selection for philopatry in high-food habitats.

Most of the previous field data for He prairie vole were obtained from a high-food (alfalfa, Medicago sativa) habitat (Getz et al., 1993). Less extensive data from a medium-food habitat (bluegrass, Poa pratensis) were also indicative of a communal social organization and natal philopatry (Getz et al, 1992). Further, the …