Ecological and Demographic Effects on Intraspecific Variation in the Social System of Prairie Dogs

Abstract

Gunnison's prairie dogs (Cynomys gunnisoni) are social North American ground squirrels whose social system has been shown to vary with food resource distributions, as predicted by the habitat variability–mating system model. We expanded this model to include the effects of variations in population densities, in addition to resource distributions, on both the social system and the individual mating strategies of Gunnison's prairie dogs. Specifically, we predicted that monogamy would be associated with uniform resources, regardless of population density, giving way to polygyny with increasing resource patchiness at intermediate densities, and to multiple males and females at high population densities. In addition, we predicted inbreeding at low densities and outbreeding at high densities on the basis of naturally low levels of genetic eity in this species. We tested these predictions by comparing social systems and mating strategies at two prairie dog colonies near Flagstaff, Arizona, during a 3—yr period of population increase. We observed variations in sociality to vary in the predicted fashion at both colonies, providing support for the plant patchiness–population density model.

The response of tree squirrels to fragmentation: a review and synthesis

“…Density is frequently associated with changes in social organisation and space use (Lott, 1991;Travis, Slobodchikoff & Keim, 1995;Kjellander et al, 2004). Increased interaction rates (Zenuto, Vassallo & Busch, 2002), increased wounding (Boonstra & Boag, 1992;Zenuto et al, 2002;Macdonald et al, 2004), increased weight loss (Macdonald et al, 2002) and reduced frequency or age of first reproduction (Wolff, Schauber & Edge, 1997;Rodel et al, 2004) can occur in high density populations.…”

Estrus and Copulation of Gunnison's Prairie Dogs

“…5). As a result, multiple paternity, in which two or more males sire offspring of a single litter (Hanken and Sherman, 1981;Keane et al, 1994), is common (Travis et al, 1996; J. L. Hoogland et aI., in litt. ).…”

MHC class II DRB diversity, selection pattern and population structure in a neotropical bat species, Noctilio albiventris

“…Animals form social groups and colonies in response to cooperative interactions as well as mating tactics. Furthermore, patterns of genetic subdivision are also shaped by the extent and nature of philopatric behaviour (Travis et al, 1995;Sommer et al, 2002;Solomon, 2003;Cutrera and Lacey, 2006). We examined the genetic structure of three different levels of social formations or units (subpopulation, roosting colonies and sexes) in our population of N. albiventris.…”