Space use and juvenile recruitment in gray-tailed volves in response to intruder pressure and food abundance

Abstract

Wolff J. O. and Schauber E. M. 1996. Space use and juvenile recruitment in gray-tailed voles in response to intruder pressure and food abundance. Acta Theriologica 41: 35-43.We examined space use by female gray-tailed voles Microtus canicaudus (Miller, 1897) and recruitment of juveniles in response to relative abundance of food and increased intruder pressure following experimental removal of habitat. Our experiment indirectly tested the assumptions of the food-defense and pup-defense hypotheses for female territoriality. Following a 70% reduction in habitat, territories of females shrunk from -50 m to < 20 m with no significant difference in pregnancy rates or overall juvenile recruitment compared to controls. Juvenile recruitment was not adversely affected by overall density or the numbers of males sharing a patch, but decreased significantly as the number of unrelated adult females sharing a patch increased. We did not measure infanticide directly, but the decreased rate of juvenile recruitment in the presence of adult females but not males suggests that pup mortality rather than food limitation contributed to reduced juvenile recruitment. We conclude that at high densities, increased intruder pressure from adult females had a greater impact on juvenile recruitment than did food abundance. Thus, our results suggest that patterns of space use, reproductive rates, and juvenile recruitment were more consistent with the pup-defense than the food-defense hypothesis for female territoriality.

Social organization of the vole Clethrionomys rufocanus and its demographic and genetic consequences: A review

“…gapperi, Clulow et al 1982). Infanticide by unfamiliar females and/or males is also suggested in other small rodents (Wolff and Cicirello 1991;Lambin and Krebs 1993;Mappes et al 1995;Wolff and Schauber 1996;Wolff 1997;Lambin and Yoccoz 1998). However, the influence of dispersers on the reproduction and survival of resident individuals is unknown in the gray-sided vole.…”

Territorial behaviour in corn mice, Calomys musculinus (Muridae: Sigmodontinae), with regard to mating system

“…Consequently, the females' time available for mate choice should be highly constrained by the tradeoff between the time and energy spent on finding a new mate, nursing and protecting their offspring (Klemme et al 2006). In species with a promiscuous-polygynous mating system, females display intrasexual territorial behaviour to protect nestlings from infanticidal females, since males rarely commit infanticide (Wolff 1993;Wolff and Schauber 1996;Wolff and Peterson 1998;Bond and Wolff 1999;Getz et al 2005).…”

Social biology of rodents

“…Also, it has been difficult to demonstrate experimentally that food shortage is a sufficient factor in limiting reproduction or population growth in rodents. Studies with several species of Microtus in enclosures have shown that populations typically reach 2-10-times higher densities than in unenclosed populations (Wolff & Schauber 1996;Wolff & Sherman 2007). These results suggest that normal dispersal, predation and other factors limit population growth before food resources are exhausted.…”