Study on the reproductive isolation and speciation of the Fejervarya limnocharis complex from Asia

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The rice frog (Fejervarya limnocharis) is one of the most widely distributed species among Asian frogs. While there is little morphological difference within the species, there are significant differences in mating calls and genetic traits between and within populations of this species. Therefore Fejervarya limnocharis (henceforth referred to as the F. limnocharis complex) is considered to be a composite of many different species. The purpose of this study is to determine (1) which species is exactly referred to as the scientific name of Fejervarya limnocharis, (2) how much genetic divergence occurs in this complex from the entire Asia, and what geographical distribution patterns it has, (3) what correlation the genetic divergence of this complex has with the occurrence and mechanism of reproductive isolation, and (4) whether it is valid to separate this species complex from the genus Rana and include it in the genus Fejervarya. In this study, first, samples of the E limnocharis comple … More x were collected from a wide range of distribution areas in Asia. Using them, extensive hybridization experiments were performed. Based on the results, the occurrence and mechanism of reproductive isolation as well as its levels were identified. Consequently, the species diversity of the complex was directly demonstrated based on the biological species concept. The diversity of the species could be uniquely demonstrated in terms of reproductive isolation mechanism only in the Institute for Amphibian Biology, because our Institute has a complete set of breeding equipment and hybridization systems. Also in this study, DNA and allozyme analyses and morphometric measurements were performed to estimate the degree of genetic divergence within the complex. Comparing these. estimations with the results of the above hybridization experiments, the diversity of the complex was demonstrated from multiple viewpoints and a more objective and reliable system was established for classification of the complex that had not been clearly defined. The present results can greatly contribute to the studies on diversity and classification in the species complex of many animals. Less