Dispersal, Mating Events and Fine-Scale Genetic Structure in the Lesser Flat-Headed Bats

<div><p>Population genetic structure has important consequences in evolutionary processes and conservation genetics in animals. Fine-scale population genetic structure depends on the pattern of landscape, the permanent movement of individuals, and the dispersal of their genes during temporary mating events. The lesser flat-headed bat (<em>Tylonycteris pachypus</em>) is a nonmigratory Asian bat species that roosts in small groups within the internodes of bamboo stems and the habitats are fragmented. Our previous parentage analyses revealed considerable extra-group mating in this species. To assess the spatial limits and sex-biased nature of gene flow in the same population, we used 20 microsatellite loci and mtDNA sequencing of the ND2 gene to quantify genetic structure among 54 groups of adult flat-headed bats, at nine localities in South China. AMOVA and <em>F</em>_ST estimates revealed significant genetic differentiation among localities. Alternatively, the pairwise <em>F</em>_ST values among roosting groups appeared to be related to the incidence of associated extra-group breeding, suggesting the impact of mating events on fine-scale genetic structure. Global spatial autocorrelation analyses showed positive genetic correlation for up to 3 km, indicating the role of fragmented habitat and the specialized social organization as a barrier in the movement of individuals among bamboo forests. The male-biased dispersal pattern resulted in weaker spatial genetic structure between localities among males than among females, and fine-scale analyses supported that relatedness levels within internodes were higher among females than among males. Finally, only females were more related to their same sex roost mates than to individuals from neighbouring roosts, suggestive of natal philopatry in females.</p> </div

Correlogram plots of the genetic autocorrelation coefficient (<i>r</i>) as a function of distance.

<p>Upper (U) and lower (L) confidence limits (two red lines) bind the 95% confidence interval about the null hypothesis of no spatial structure for the combined data set as determined by 1000 permutations. (A) all individuals (n = 296), (B) females (n = 227), (C) males (n = 69).</p

Distribution of the nine sampled localities of <i>Tylonycteris pachypus</i> from Chongzuo District, Guangxi Province, China.

<p>The left part shows the sampled roosting groups as dark dots in each locality (some dots are overlapped, given some groups coming from the same bamboo clusters).</p

Global spatial autocorrelation analysis of all 296 individuals.

<p>N: number of pairwise comparisons; <i>r</i>: correlation coefficient; U and L: upper and lower bounds for the 95% confidence interval about the null hypothesis of no spatial structure, U<i>r</i> and L<i>r</i>: 95% error bounds about r as determined by bootstrap resampling. The probability <i>P</i> of a one-tailed test for positive autocorrelation, permutated <i>r</i> and bootstrapped <i>r</i> are also shown.</p

Hierarchical analyses of molecular variance (AMOVA) from microsatellite data and mtDNA data (in parenthesis), separately.

<p><i>F</i>_CT indicates the degree of differentiation among two regions (Longzhou region vs. Ningmin region); <i>F</i>_SC indicates the degree of differentiation among localities within regions; <i>F</i>_ST indicates the degree of differentiation within localities.</p

Distribution of pairwise <i>F</i>_ST among roosting groups within localities (from microsatellite data).

<p>Distribution of pairwise <i>F</i>_ST among roosting groups within localities (from microsatellite data).</p

Distributions of pairwise relatedness values within internodes in each locality from microsatellite data.

<p>(A) females within internodes (locality numbers = 8), (B) males within internodes (locality numbers = 3), (C) females between internodes (locality numbers = 8), (D) males between internodes (locality numbers = 6). NA, missing plot because of less than five comparisons within localities. Values within each plot stand for mean±SD.</p

Pairwise <i>F</i>_ST estimates for genetic differentiation among localities.

<p>Below the diagonal for microsatellite data and above the diagonal for mtDNA data. KC locality was deleted because of less than five samples within it.</p><p>Significance level:</p>*<p><i>P</i><0.05,</p>**<p><i>P</i><0.01.</p

Occurrence_data

GPS coordinates of the occurrence records used in building MaxEnt models of the four Taiwanese bat species

Bioclimatic_layers_current

The eight selected bioclimatic layers for current conditions used in building MaxEnt models of the four Taiwanese bat species. An additional layer where Taiwan is masked (119.9-122.1ºE, 21.8-25.5ºN) is provided