Sociality and genetics of a southeastern Arizona coati (Nasua narica) population
Abstract
White-nosed coatis (Nasua narica) are social carnivores that range from the neotropics into the southwestern United States. The majority of previous coati research has focused on tropical populations, where resources are plentiful and density of individuals is high. My study examined effects of differing ecological conditions on the behavior and genetics of coatis at their northern range terminus. The goal of my research was to determine whether the social system found in temperate zone coatis mirrors sociality described in tropical studies. Previous results have characterized coati females as social, living in large closely related matrilines. Adult males are thought to be solitary. Tropical research has shown a sex-bias in dispersal with males dispersing socially, but not spatially from their natal ranges. Inbreeding avoidance, if it occurs, is thought to occur via male forays from natal ranges during breeding. I used a combination of radio telemetry and microsatellite DNA analyses to examine coati behavior in Chiricahua National Monument, Arizona, from 1996-1999 and 2001-2004. I paid particular attention to the dynamic nature of individual associations and devised a novel use of a methodology first proposed by Doncaster (1990). Adult females in my population did not adhere to the previous characterization of "bands" as closely associating groups of individuals. While adult females were closely related to band members, and spent more time associating with these individuals, interactions between individuals were remarkably loose for a purportedly social species. Density of individuals influenced number of bands in Chiricahua, with more bands at higher densities. Number of females per band remained constant irrespective of density, suggesting an optimal group size. Although adult males in Chiricahua conform to the prediction of being solitary, they dispersed both socially and spatially from their natal ranges. Both females and males in my study area exhibited natal and secondary dispersal. Relatedness of males to their closest female band was relatively low during breeding and non-breeding seasons. Instead of using male forays to avoid inbreeding as is hypothesized in tropical populations, Chiricahua coatis appear to avoid inbreeding via dispersal.
Degree
Ph.D.
Advisors
Waser, Purdue University.
Subject Area
Ecology
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