Fine-scale population structure and sex-biased dispersal in bobcats (Lynx rufus) from southern Illinois

Abstract

In mammal populations, the spatial and genetic structure can be affected by dispersal, philopatry, and relatedness. Bobcats ( Lynx rufus (Schreber, 1777)) are thought to exhibit typical mammalian dispersal behaviour where males disperse and females are philopatric, potentially leading to higher relatedness among females compared with males. We used 10 microsatellite loci to examine population structure and sex-biased dispersal in 146 bobcats sampled in southern Illinois during 1993–2001 using population genetic descriptive statistics, a Bayesian clustering algorithm, relatedness (rxy), and autocorrelation analyses. A randomization test demonstrated that female dyads had significantly higher rxy values with respect to randomly selected dyads (rxy = 0.093 ± 0.222, P = 0.012) and spatial autocorrelation analyses determined that females in close proximity (<5 km) had a high probability of being related (P = 0.001). Conversely, rxy values for males were not different from the null distribution (rxy = 0.019 ± 0.122, P = 0.3158) and no significant relationships were found with spatial autocorrelation analysis. Additionally, it was demonstrated that bobcats in southern Illinois approximated a panmictic population with no obvious barriers to gene flow. The pattern of relatedness observed in this study confirmed that females were philopatric and males dispersed, corroborating existing observational data for this species.