Population Genetics and and Phylogeny of the Bush Brown Butterfly in Genus Mycalesis Hubner, 1818 (Lepidoptera: Nymphalidae) in Peninsular Thailand

Abstract

Thailand is located in tropical rainforest with rich in biodiversity, especially peninsular Thailand, which is an important transition zone of fauna between the Indo-Chinese and Sundaic sub-regions. Mycalesis radiated spectacular in Southeast Asia and Australia, there are two distinct seasonal morphs (wet and dry season form). In dry season form, the submarginal ocelli pattern on the underside of wing is reduced that make difficult for identification. The aims of this study were observed species and identification, investigated genetic variation and phylogenetic relationships of Mycalesis in peninsular Thailand. The survey of Mycalesis in peninsular Thailand was conducted in 6 provinces, comprising of Chumphon, Surat Thani, Nakhon Si Thammarat, Phangnga, Trang and Narathiwat during February 2015 to July 2016. The adult specimens were collected by using insect nets and fruit-baited traps, then wing setting, photographs and genitalia dissections were carried out. Mitochondrial gene (COl) and two nuclear gene (EF-la and wingless) were investigated to study the genetic variation and constructed phylogenetic relationships in Mycalesis populations. Totally 214 Mycalesis specimens were collected, that could be identified to seven species; M. intermedia, M. perseus, M. perseoides, M. visala, M. orseis, M. janardana and M. mineus. In this study, two distinct seasonal morphs were found as wet and dry season forms, male genitalia also were described. Difference of genetic variation was found in each gene of Mycalesis species, but present as low in all genes of M. mineus. Phylogenetic relationships based on combined gene sequences indicated that the Mycalesis was monophyletic group, which Mineus group can be divided into two major clades. Estimating divergence time of Mycalesis in peninsular Thailand was 32.47 mya in Oligocene period.