Comparative Population Structure in Species of Bats Differing in Ecology and Morphology in the Andaman Islands, India

Chakravarty, Rohit; Chattopadhyay, Balaji; Ramakrishnan, Uma; Sivasundar, Arjun

doi:10.3161/15081109acc2018.20.1.006

Cited by 6 publications

(6 citation statements)

References 49 publications

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“…Our results on the haplotype distribution are comparable to a phylogeography study on Bat populations on the Andaman Islands; Middle Andaman Island houses maximum haplotype diversity and shared haplotypes with surrounding smaller islands reflecting the larger area and a potential source population ( Chakravarty et al, 2018 ).…”

Section: Discussionsupporting

confidence: 85%

Population structure in the Andaman keelback,Xenochrophis tytleri: geographical distance and oceanic barriers to dispersal influence genetic divergence on the Andaman archipelago

Swamy

Shanker

2018

PeerJ

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Limited gene flow between populations due to geographic distance, presence of barriers or inherent low dispersal ability leads to the formation of genetically structured populations. Strong population structure indicates lowered levels or absence of gene flow which might lead to inbreeding and loss of genetic capacity to recuperate from anthropogenic stress and natural calamities. Terrestrial reptiles are generally known to have low dispersal abilities and few studies have explored drivers of their population structure on continental islands, where both anthropogenic stress and natural calamities are relatively common. We investigated the population structure and drivers of diversification of the Andaman keelback (Xenochrophis tytleri), an endemic, terrestrial and freshwater snake species in the Andaman archipelago, a continental group of islands in the Bay of Bengal. Data was collected from 86 individuals from seven islands and 78 individuals were sequenced for the gene Nuclear Dehydrogenase subunit 4 to identify the number of populations and distribution of genetic diversity across populations. We found 11 haplotypes on seven islands and observed high genetic differentiation between seven populations defined island-wise (FST = 0.82). We further tested the number of populations by incorporating spatial data into Bayesian Clustering Analysis (GENELAND) and identified six populations of the Andaman keelback. We tested for the influence of Isolation-by-distance on these populations. While the overall trend showed a positive correlation between geographic and genetic distance, a correlogram revealed that the positive correlation disappears beyond ∼20–40 km. We also tested for the presence of geographical barriers to gene flow using Monmonier’s algorithm (SPADS), which identified five barriers to dispersal confirming that there are oceanic barriers to dispersal for some island populations of the Andaman keelback. As the Andaman Islands are arranged almost in a straight line from North to South, our data are insufficient to tease apart the roles of geographical distance and barriers to gene flow. We conclude that salt waters between near islands are weak barriers and as the geographical distance between islands increases, so does the strength of the barrier.

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Section: Discussionsupporting

confidence: 85%

Population structure in the Andaman keelback,Xenochrophis tytleri: geographical distance and oceanic barriers to dispersal influence genetic divergence on the Andaman archipelago

Swamy

Shanker

2018

PeerJ

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“…A recent haplotype network study [47] suggests that the populations of R . andamanensis from Little Andaman should be considered as distinct evolutionarily significant units.…”

Section: Discussionmentioning

confidence: 99%

Integrated approaches to identifying cryptic bat species in areas of high endemism: The case of Rhinolophus andamanensis in the Andaman Islands

Srinivasulu

Srinivasulu²,

Srinivasulu

et al. 2019

PLoS ONE

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The diversity of bats worldwide includes large numbers of cryptic species, partly because divergence in acoustic traits such as echolocation calls are under stronger selection than differences in visual appearance in these nocturnal mammals. Island faunas often contain disproportionate numbers of endemic species, and hence we might expect cryptic, endemic species to be discovered relatively frequently in bats inhabiting islands. Species are best defined when multiple lines of evidence supports their diagnosis. Here we use morphometric, acoustic, and molecular phylogenetic data to show that a horseshoe bat in the Andaman Islands is distinct in all three aspects, supporting its status as a distinct species. We recommend investigation into possible new and endemic bat species on islands by using integrated approaches that provide independent lines of evidence for taxonomic distinctiveness. We provide a formal redescription of the taxon newly raised to species level, Rhinolophus andamanensis Dobson, 1872.

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“…5). A study on bats of the Andaman Islands also found unique mitochondrial haplotypes on Little Andaman Island in three species 12 . However, considering the microsatellite allelic diversity and distribution in island populations of the Andaman day gecko, we speculate that haplotypes from other islands could be present in Little Andaman and could be detected through more extensive sampling.…”

Section: Discussionmentioning

confidence: 93%

“…There are just a handful of studies attempting to understand the effects of relatively recent island separation on populations of endemic terrestrial fauna in the Andaman Islands. Phylogeographic studies on four bat species 12 and the Andaman keelback snake (Fowlea tytleri (Blyth, 1863)) 13 showed substantial levels of genetic diversity, structure and varying degrees of inter-island population differentiation in mitochondrial DNA.…”

mentioning

confidence: 99%

The Andaman day gecko paradox: an ancient endemic without pronounced phylogeographic structure

Orozco‐terWengel

Shanker

Vences³

2020

Sci Rep

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the Andaman day gecko (Phelsuma andamanensis) is endemic to the Andaman Archipelago, located ~ 6000 km away from Madagascar where the genus Phelsuma likely evolved. We complemented existing phylogenetic data with additional markers to show that this species consistently branches off early in the evolution of the genus Phelsuma, and this early origin led us to hypothesize that island populations within the Andaman Archipelago could have further diversified. We sampled the Andaman day gecko from all major islands in the Andamans, developed new microsatellite markers and amplified mitochondrial markers to study population diversification. We detected high allelic diversity in microsatellites, but surprisingly poor geographical structuring. This study demonstrates that the Andaman day gecko has a panmictic population (K = 1), but with weak signals for two clusters that we name 'North' (North Andaman, Middle Andaman, Interview, Baratang, Neil, and Long Islands) and 'South' (Havelock, South Andaman, Little Andaman Islands). the mitochondrial coi gene uncovered wide haplotype sharing across islands with the presence of several private haplotypes (except for the Little Andaman Island, which only had an exclusive private haplotype) signalling ongoing admixture. This species differs from two other Andaman endemic geckos for which we provide comparative mitochondrial data, where haplotypes show a distinct phylogeographic structure. Testing population history scenarios for the Andaman day gecko using Approximate Bayesian Computation (ABC) supports two possible scenarios but fails to tease apart whether admixture or divergence produced the two weak clusters. Both scenarios agree that admixture and/or divergence prior to the onset of the last glacial maximum shaped the genetic diversity and structure detected in this study. ABC supports population expansion, possibly explained by anthropogenic food subsidies via plantations of cash crops, potentially coupled with human mediated dispersal resulting in the observed panmictic population. The Andaman day gecko may thus be a rare example of an island endemic reptile benefiting from habitat modification and increased movement in its native range. Populations evolve as a result of changing demographic characteristics influenced by habitat components and structure, seasonal availability of resources, individual interactions, and other species-specific variables. While vicariance biogeography posits stable species communities on islands over long periods, island biogeography theory predicts high species turnover as a result of colonization and extinctions, but most empirical studies fall in the intermediate zone with varying levels of geneflow and dispersal across neighbouring islands 1. The resultant complex demographic histories leave signatures in the genetic makeup of organisms 2 , where the genome functions as an evolutionary memory of populations. Phylogeographic studies, especially on different co-distributed species, can provide insights into historical and contemporary dispers...

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Comparative Population Structure in Species of Bats Differing in Ecology and Morphology in the Andaman Islands, India

Cited by 6 publications

References 49 publications

Population structure in the Andaman keelback,Xenochrophis tytleri: geographical distance and oceanic barriers to dispersal influence genetic divergence on the Andaman archipelago

Population structure in the Andaman keelback,Xenochrophis tytleri: geographical distance and oceanic barriers to dispersal influence genetic divergence on the Andaman archipelago

Integrated approaches to identifying cryptic bat species in areas of high endemism: The case of Rhinolophus andamanensis in the Andaman Islands

The Andaman day gecko paradox: an ancient endemic without pronounced phylogeographic structure

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