Spotted turtle dispersal microsatellite DNA sex and site data

Sex-biased dispersal is common in many animals, with male-biased dispersal
often found in studies of mammals and reptiles, including interpretations
of spatial genetic structure, ostensibly as a result of male-male
competition and a lack of male parental care. Few studies of sex-biased
dispersal have been conducted in turtles, but a handful of studies, in
saltwater turtles and in terrestrial turtles, have detected male-biased
dispersal as expected. We tested for sex-biased dispersal in the
endangered freshwater turtle, the spotted turtle (Clemmys guttata) by
investigating fine-scale genetic spatial structure of males and females.
We found significant spatial genetic structure in both sexes, but the
patterns mimicked each other. Both males and females typically had higher
than expected relatedness at distances < 25 km, and in many
distance classes greater than 25 km, less than expected relatedness.
Similar patterns were apparent whether we used only loci in Hardy-Weinberg
equilibrium (n = 7) or also included loci with potential null alleles (n =
5). We conclude that, contrary to expectations, sex-biased dispersal is
not occurring in this species, possibly related to the reverse sexual
dimorphism in this species, with females having brighter colors. We did,
however, detect significant spatial genetic structure in males and
females, separate and combined, showing philopatry within a genetic patch
size of < 25 km in C. guttata, which is concerning for an
endangered species whose populations are often separated by distances
greater than the genetic patch size.