Social influences on intergroup transfer by pine voles (Microtus pinetorum)

Abstract

Selection to obtain mating opportunities is hypothesized to be a major factor in dispersal. Thus, if individuals move to another group or switch nests to maximize their reproductive opportunities, they should move to groups or sites where they minimize competition for resources or mates and where they can find potential mates. We examined movement of pine voles (Microtus pinetorum) in an orchard habitat. Males dispersed later than females, but the two sexes showed similar patterns of movement with respect to conspecifics. Males and females immigrated to territories that contained some opposite-sex conspecifics; they also immigrated to territories without same-sex conspecifics. The latter suggests that they may avoid competitors and move to territories where an opening exists. When female breeders were removed from a social group, a replacement female arrived and began to breed relatively rapidly. In control groups where breeding females were not removed, no replacement females appeared. These results suggest that pine voles, at least females, may monitor vacancies and immigrate if a vacancy appears.

Activity, range areas, and nesting patterns in the viscacha rat, Octomys mimax

“…We found no signs (e.g., mounds of fresh dirt or rocks) that O. mimax in our study population use digging to modify these resting places. Although we did not break into these locations to confirm the presence of bedding, food remnants, or other items indicative of a nest, the tendency for animals to co-occur at a rather limited number of sites is consistent with these signs recorded in other rodents (e.g., Armitage and Gurri-Glass, 1994;Lacey et al, 1997;Solomon et al, 1998;Tristiani et al, 2003;Wilkinson and Baker, 1988;Wolton, 1985) and is suggestive that these localities function as nests in viscacha rats. Overall then, these results are in agreement with Mares (1980) who labelled O. mimax as a rock-dwelling species based on the presence of indirect signs of these animals.…”

A review of the evolutionary causes of rodent group-living

“…Evidence generally supports that resource availability influences philopatry of rodents (Garrett and Franklin 1988, Jones et al 1988, Keane 1990, Boutin et al 1993, Ribble 1992, Lambin 1994, Lurz et al 1997, Gundersen and Andreassen 1998, Byrom and Krebs 1999, Solomon et al 1999. However, evidence for a more specific connection between availability of burrows and philopatry (and sociality) is much more limited.…”

Breeding characteristics of the Lusitanian pine vole, Microtus lusitanicus

“…Likewise, Fitzgerald and Madison ( 1983 ) found in a population of M. pinetorum that the principal mating system was monogamy but that polygyny and promiscuity also occurred. In fact, although monogamy may be the principal mating system in this species, polygyny and promiscuity may occur depending on the size and degree of relatedness among group members (Marfori et al 1997 ;Solomon et al 1998 ). Furthermore, it is well documented in other Microtus species with a small relative testis size that monogamy is the most common mating system but not the unique one (see Waterman, 2007 , for review).…”