Population Genetic Structure of Eonycteris robusta from Luzon Island

Abstract

Population genetics has been widely employed in conservation studies to assess genetic diversity, gene flow, and population structure. This information can be used to understand the population’s fitness. The Philippine dawn bat Eonycteris robusta is a nectarivorous fruit bat that is ecologically important because of its capability to pollinate trees. It is categorized as “Vulnerable” in the Philippine Red List and the IUCN (International Union on the Conservation of Nature) Red List. Fragmentation and loss of forest habitats along with biogeographical factors might impact gene flow and affect the genetic diversity of this species. Thus, a population genetic study was done to assess gene flow and population structure of this species from two sites in the island of Luzon: Palanan, Isabela and Puning Cave, Doña Remedios Trinidad, Bulacan. Ten (10) microsatellite markers were developed from the whole genome of E. robusta and these were used for genotyping individuals. Observed heterozygosity (Ho) was generally lower than the expected (He), suggesting loss of heterozygosity. The inbreeding coefficient values (F) across all loci were greater than 0.5, which meant that mating between closely related individuals was frequent. A low level of gene flow was detected between Palanan and Puning Cave with the presence of structuring (Fst = 0.190 ± 0.003; Nm = 1.068 ± 0.020). Deviations from the Hardy-Weinberg equilibrium (HWE) were also observed for most of the loci tested. Clustering was also evident in the principal coordinates analysis (PCoA) plots, showing a distinct cluster of Puning Cave samples separate from Palanan, Isabela. This study has shown that within island clustering is possible, which may be driven by ecological factors such as discontinuity of available habitats for E. robusta or by biogeographical features like distance and topography.