Do both sexes disperse and does one sex disperse further than the
other?
Our results indicate that both sexes dispersed. There were no
significant differences between adult females and males in mean mtDNA
haplotype diversity (0.945 in females, 0.924 in males, permutation test
p = 0.766), mtDNA nucleotide diversity (0.027 in females, 0.029 in
males, permutation test p = 0.699), mean relatedness r (-0.013 in
females, -0.056 in males, mean difference -0.040, lying within the 95%
confidence interval (-0.048 – 0.054) obtained by bootstrapping) or mean
heterozygosity HL (0.184 in females, 0.216 in males, paired t-test p =
0.438).
Dispersal was most likely opportunistic, as we did not find a spatial
genetic structure in our study population. The correlation between
genetic and spatial distances was not significant for neither sex, as
the 95 % CI of autocorrelation r values overlapped zero for all
distance classes (Supplementary Table 2, Fig. S1). The correlation
between mtDNA haplotype distances and spatial distances in females was
not significant either (Mantel correlation = 0.048, n = 91 dyads,
right-tailed p = 0.342). The direct observation of dispersal (see
below), the pattern of relatedness and the loose geographic clustering
of the mtDNA haplotype network (most of the closely related haplotypes
were sampled at nearby locations, Fig. 2) show that individuals often
disperse over short distances. In one observed case, a young male
dispersed to an unoccupied area adjacent to his natal group, and in five
more cases, close-range dispersal events in the past could be inferred
from the fact that adult first-degree kin occupied home ranges that were
either adjacent or separated by 1–2 home ranges (Fig. 1). At the same
time, the lack of spatial genetic structure or clear mtDNA haplotype
clustering indicates that individuals also migrate further.