The effects of heterozygosity on home range size and inbreeding depression in a salamander with limited dispersal

Background/Question/Methods

Inbreeding depression is often detectable as heterozygosity-fitness correlations (HFCs). These HFCs are typically small in magnitude, a result often attributed to power of the analyses and markers’ representation of global heterozygosity. Animal behaviors often affect fitness and are affected by genetics, at least in part. We hypothesized that heterozygosity influences behavior, which ultimately results in HFCs after dilution by environmental plasticity of behavior. Specifically, in red-backed salamanders, Plethodon cinereus, which have limited dispersal and the potential for inbreeding, we use a mark-recapture study and experimental enclosures combined with heterozygosity estimates from microsatellite DNA to test whether heterozygosity affected foraging behavior (home range size) and fitness (juvenile growth and survival). 

Results/Conclusions

We found that salamanders with higher heterozygosity had larger home ranges. Salamanders with higher heterozygosity also grew faster in the wild and in enclosures. However, we found no effects of heterozygosity on survival, likely because of a tradeoff between foraging activity and predation risk in P. cinereus. We conclude that, because foraging behavior in P. cinereus is tightly linked to food uptake and mass gain, heterozygosity influences growth via effects on foraging behavior. Future research should investigate how the relationship between heterozygosity, behavior, and fitness may be affected or mediated by endocrine or immune systems.