The influence of density and sex on patterns of fine-scale genetic structure.
Natal philopatry is expected to limit gene flow and give rise to fine-scale spatial genetic structure (SGS). The banner-tailed kangaroo rat (Dipodomys spectabilis) is unusual among mammals because both sexes are philopatric. This provides an opportunity to study patterns of local SGS faced by philopatric and dispersing animals. We evaluated SGS using spatial genetic autocorrelation in two D. spectabilis populations (Rucker and Portal) over a 14-year temporal series that covered low, medium, and high population densities. Significantly positive autocorrelation values exist up to 800 m at Rucker and 400 m at Portal. Density was negatively associated with SGS (low >medium >high), and suggests that increases in density are accompanied by greater spatial overlap of kin clusters. With regard to sex-bias, we find a small but significant increase in the SGS level of males over females, which matches the greater dispersal distances observed in females. We observed variation in SGS over the ecological time scale of this study, indicating genetic structure is temporally labile. Our study is the first temporal exploration of the influence of density and sex on spatial genetic autocorrelation in vertebrate populations. Because few organisms maintain discreet kin clusters, we predict that density will be negatively associated with SGS in other species.
Busch
Joseph D
JD
Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, USA. joedbusch@gmail.com
Waser
Peter M
PM
DeWoody
J Andrew
JA
D025041:Animal Migration; D000818:Animals; D001130:Arizona; D004173:Dipodomys / Q000235:genetics*; D017753:Ecosystem; D005260:Female; D005819:Genetic Markers; D040342:Genetic Structures; D005828:Genetics, Population; D008297:Male; D011156:Population Density; D012737:Sex Factors
D005819:Genetic Markers