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

Similarity of dispersal behavior among siblings is common invertebrates. However, little is known about the factors (genetic,prenatal, postnatal) generating this similarity. Here we analyzedpotential influences on the dispersal patterns of multiple familiesof hatchling fence lizards, Sceloporus occidentalis. We capturednear-term females from the field, incubated their eggs in thelaboratory, 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 measuredthe direct distance to the release site. Because we treatedhatchlings (from eggs to release) randomly with respect to sibship,we eliminated the possibility that any observed sibling similarityin dispersal is merely an artifact of common postnatal influences.To analyze dispersal, we developed a new method that does notmake an arbitrary choice of a threshold distance separatingdispersers from nondispersers. We found a significant familyeffect on dispersal. We suspect that this family effect originatesfrom genetic influences rather than from prenatal ones. Indeed,hatchling dispersal was remarkably unrelated to numerous traits(of clutches, mothers, or hatchlings) that might reflect prenataleffects. However, we did find that males were more likely todisperse than females, as predicted for polygynous species.Finally, characteristics of the release site did not appearto influence dispersal.