Phylogeography of the black fly Simulium tani (Diptera: Simuliidae) from Thailand as inferred from mtDNA sequences

Abstract

Intraspecific phylogeography has been used widely as a tool to infer population history. However, little attention has been paid to Southeast Asia despite its importance in terms of biodiversity. Here we used the cytochrome oxidase I gene of mitochondrial DNA (mtDNA) for a phylogeographic study of 147 individuals of the black fly Simulium tani from Thailand. The mtDNA revealed high genetic differentiation between the major geographical regions of north, east and central/south Thailand. Mismatch distributions indicate population expansions during the mid-Pleistocene and the late Pleistocene suggesting that current population structure and diversity may be due in part to the species' response to Pleistocene climatic fluctuations. The genealogical structure of the haplotypes, high northern diversity and maximum-likelihood inference of historical migration rates, suggest that the eastern and central/southern populations originated from northern populations in the mid-Pleistocene. Subsequently, the eastern region had had a largely independent history but the central/southern population may be largely the result of recent (c. 100,000 years ago) expansion, either from the north again, or from a relictual population in the central region. Cytological investigation revealed that populations from the south and east have two overlapping fixed chromosomal inversions. Since these populations also share ecological characteristics it suggests that inversions are involved in ecological adaptation. In conclusion both contemporary and historical ecological conditions are playing an important role in determining population genetic structure and diversity.

Mitochondrial DNA variation in the malaria vector Anopheles minimus across China, Thailand and Vietnam: evolutionary hypothesis, population structure and population history

“…Signals of expansion from multiple forest species are most likely to be a response to a common factor. As we have suggested previously, this factor seems most likely to be the spread of forests from refugial areas following the onset of an interglacial period (Chen et al, 2004;Pramual et al, 2005;O'Loughlin et al, 2008). The divergence of Lineages A and B, which dates to B1 mya using the conventional calibration rate for animal mtDNA of 2% divergence per million years (Powell et al, 1986), has likely accumulated over multiple glacial cycles.…”

“…As the confidence intervals of these estimates overlap, the expansions could have occurred at the same time. Other forest insect species from Indochina show similarly dated genetic signals of expansion for mtDNA: A. dirus (O'Loughlin et al, 2008), Simulium tani blackflies (Pramual et al, 2005) and Anopheles jeyporiensis (Chen et al, 2004). Stone oaks in mainland (but not insular) Southeast Asia also have a star-like chloroplast DNA genealogy characteristic of demographic expansion (Cannon and Manos, 2003).…”

Global population structure of the stable fly (Stomoxys calcitrans) inferred by mitochondrial and nuclear sequence data

“…Recent expansions in a variety of disease vectors, such as Anophelinae (Donnelly et al, 2001;Dusfour et al, 2007;Matthews et al, 2007), and black flies (Pramual et al, 2005) appear to be tied to human population expansions and/or to climate changes and to the rise of agriculture, providing significant new breeding sites and sources of bloodmeals (Coluzzi, 1982). Coluzzi (1982) proposed that because these species were dependent on humans for feeding and breeding sites, populations may have mirrored the growth in populations of humans and domestic animals during this period.…”

Population genetic structure of Simulium degrangei (Diptera: Simuliidae) from Western Carpathians

“…Five out of six analyzed sibling species were identified based on sequences of 16S rRNA and NADH dehydrogenase subunit 4 genes . In Simulium tani Takaoka & Davies, 1995 the cytochrome oxidase I (COI) of mtDNA was successfully used for resolving phylogeographical questions in Thailand (Pramual et al 2005). The same gene was successfully used for discrimination between Simulium reptans Linnaeus, 1758 and Simulium galeratum Edwards, 1920, where the status of the species on the morphological basis was ambiguous (Day et al 2008), and it was also able to separate the four very similar species from the aureum group in Britain (Day et al 2010).…”