Diversification in subtropical mountains: Phylogeography, Pleistocene demographic expansion, and evolution of polyphenic mandibles in Taiwanese stag beetle, Lucanus formosanus

Jen Pan Huang, Chung Ping Lin

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Pleistocene glacial oscillations have had profound impacts on the historical population dynamics of extant species. However, the genetic consequences of past climatic changes depend largely on the latitude and topography of the regions in question. This study investigates the effect of Pleistocene glacial periods and the Central Mountain Range on the phylogeography, historical demography, and phenotypic differentiation of a montane forest-dwelling stag beetle, Lucanus formosanus (Coleoptera: Lucanidae), which exhibits extensive mandible variations across mountain ranges in subtropical Taiwan. Analyses of mitochondrial (cox1) and nuclear (wg) loci reveal that L. formosanus originated nearly 1.6 million years ago (Mya) in the early Pleistocene period and consisted of geographically overlapping Alishan and Widespread clades. A drastic population expansion starting approximately 0.2 Mya in the Widespread clade likely resulted from altitudinal range shift of the temperate forests, which was closely tied to the arrival of the Riss glacial period in the late Middle Pleistocene. A ring-like pattern of historical gene flow among neighboring populations in the vicinity of the Central Mountain Range indicates that the mountains constitute a strong vicariant barrier to the east-west gene flow of L. formosanus populations. A geographic cline of decreasing mandible size from central to north and south, and onto southeast of Taiwan is inconsistent with the low overall phylogeographic structures. The degree of mandible variation does not correlate with the expected pattern of neutral evolution, indicating that the evolutionary diversification of this morphological weapon is most likely subject to sexual or natural selection. We hypothesize that the adaptive evolution of mandibles in L. formosanus is shaped largely by the habitat heterogeneity.

Original languageEnglish
Pages (from-to)1149-1161
Number of pages13
JournalMolecular Phylogenetics and Evolution
Volume57
Issue number3
DOIs
Publication statusPublished - 2010 Dec 1

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Keywords

  • Central mountain range
  • Demographic expansion
  • Exaggerated weapon
  • Lucanidae
  • Morphological cline
  • Pleistocene
  • Stag beetles

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics

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