วงศ์วานวิวัฒนาการของด้วงมูลสัตว์สกุล Onthophagus ในคาบสมุทรไทย / อรทิพย์ วรานุศิษฏ์

Abstract

The study of phylogenetic relationships of dung beetles genus Onthophagus Latreille, 1802 in peninsular Thailand were collected during May, 2014 to January, 2016 at seven sampling sites in the forests using fresh's pig dung in baited pitfall traps. The objectives of this study were to investigate the phylogenetic relationships and genetic variation of Onthophagus in peninsular Thailand. The molecular phylogeny was analyzed using three genes from mitochondrial (COI, 16S rDNA and Cyt b), one gene of nucleus (28S rDNA domain3) and the combination of the three genes (COI, 16S rDNA and Cyt b). The result showed that 969 individuals of 33 species in 3 genus (Onthophagus, Copris and Liatongus) in peninsular Thailand were collected and 19 Onthophagus species were identified. In this study, the effective genes to investigate the phylogeny were COI, 16S rDNA, Cyt b and combined three genes. The results strongly support a monophyly of Onthophagus species in peninsular Thailand. Moreover, several species (O. orientalis, O. maniti, O. rugicollis and O. vulpes) are closely related species (sister groups). However, the 28S rDNA domain3 did not clearly explain the genetic relationships in this study. The result of phylogenetic tree of COI based on the divergence time of speciation suggested that the origin of Onthophagus species in peninsular Thailand is approximately about 33.06 million years ago (MYA), and O. uenol and O. laevis is the oldest (33.06 MYA) and O. babirussa (0.69 MYA) is the youngest population in peninsular Thailand. Additionally, the genetic variation in population of Onthophagus species in peninsular Thailand was detected, for example O. babirussa the dominant species in peninsular Thailand. The haplotype network suggested that O. babirussa was originated in the Phuket mountain range in Phang-Nga Province and also expanded to the San Kala Khiri mountain range. In addition, genetic differentiation was supported by the correlation between genetic distance with geographic distance.