Color-Biased Dispersal Inferred by Fine-Scale Genetic Spatial Autocorrelation in a Color Polymorphic Salamander

Behavioral traits can be influenced by predation rates of color morphs, potentially leading to reduced boldness or increased escape behaviors in one color morph. The red-backed salamander, Plethodon cinereus, is a small terrestrial salamander whose color morphs have different diets and select different microhabitats, but little is known about potential differences in dispersal behaviors. We used fine-scale genetic spatial autocorrelation to examine 122 P. cinereus in a color-polymorphic population at 10 microsatellite loci in order to generate estimates of spatial genetic structure for each color morph. Differences in spatial genetic structure have been used extensively to infer within-population sex-biased dispersal but have never been used to test for dispersal differences between other groups within populations such as color morphs. We found evidence for color-biased dispersal, but not sex-biased dispersal. Striped salamanders had significant positive genetic structure in the shortest distance classes indicating philopatry. In contrast, unstriped salamanders showed a lack of spatial genetic structure at shorter distances and higher than expected genetic similarity at further distances, as expected if they are dispersing from their natal site. These results show that genetic methods typically used for sex-biased dispersal can be used to investigate differences in dispersal between morphs that vary discretely in polymorphic populations, such as color morphs.