Genetic, prenatal, and postnatal correlates of dispersal in hatchling fence lizards (Sceloporus occidentalis)

Similarity of dispersal behavior among siblings is common in vertebrates. However, little is known about the factors (genetic, prenatal, postnatal) generating this similarity. Here we analyzed potential influences on the dispersal patterns of multiple families of hatchling fence lizards, Sceloporus occidentalis. We captured near-term females from the field, incubated their eggs in the laboratory, measured various traits of the hatchlings and dams, and then released the hatchlings at a number of sites in nature. We recaptured hatchlings 5-6 weeks later and measured the direct distance to the release site. Because we treated hatchlings (from eggs to release) randomly with respect to sibship, we eliminated the possibility that any observed sibling similarity in dispersal is merely an artifact of common postnatal influences. To analyze dispersal, we developed a new method that does not make an arbitrary choice of a threshold distance separating dispersers from nondispersers. We found a significant family effect on dispersal. We suspect that this family effect originates from genetic influences rather than from prenatal ones. Indeed, hatchling dispersal was remarkably unrelated to numerous traits (of clutches, mothers, or hatchlings) that might reflect prenatal effects. However, we did find that males were more likely to disperse than females, as predicted for polygynous species. Finally, characteristics of the release site did not appear to influence dispersal.