Population genetic structure of giant wood spider Nephila maculata (Araneae, Tetragnathidae) in Taiwan based on mitochondrial cytochrome oxidase I partial sequence.
Currently, most phylogeographic studies of terrestrial animals in Taiwan focus on vertebrates. Results from most studies showed that terrestrial vertebrates could be divided into eastern and western groups according to their population genetic structures. The common phylogeographic pattern exhibited by so many taxa was suggested to result from the upheaval of the Central Mountain Ridge, which led to isolation and differentiation of eastern and western populations. In this study, the widely-distributed giant wood spider Nephila maculata (Fabricius 1793) is used to investigate if population differentiation pattern of Taiwanese terrestrial arthropods resembles that of terrestrial vertebrates. Mitochondrial cytochrome oxidase I (COI) is used as genetic marker and its partial sequence is determined in 189 specimens collected from 24 localities in Ryukyu Islands, Taiwan and China. The 617 bases of COI gene are successfully amplified from DNA extracted from leg muscle and 11 haplotypes are identified from all specimens examined. Phylogenetic trees constructed by neighbor-joining (NJ) and maximum parsimony (MP) methods using Nephila clavata Koch 1877 and Nephila antipodiana (Walckenaer 1841) as the outgroups indicate that N. maculata populations can be separated into two major lineages, group A and group B, with high bootstrap values (99% in NJ tree and 100% in MP tree). Group A consists of most specimens from twenty-three localities. Group B consists of specimens from southeastern China and northwestern Taiwan. Another minor lineage is group C, which consists of 3 specimens from northeastern Taiwan. The wide distribution of the EA haplotype in western and eastern Taiwan indicats that the population differentiation pattern of N. maculata is different from those of terrestrial vertebrates examined so far. Central Mountain Ridge does not seem to be a major geographic barrier to N. maculata. The cooccurrence of specimens with EA haplotype in Taiwan and China suggests that some of the present populations in Taiwan might have splited from an ancestral population in mainland. In addition, judging from phylogenetic trees and the distribution patterns of haplotypes, entry of N. maculata from China to Taiwan might have occurred several times.
Updated: Mar-10-2014 01:22:51 (Taiwan, GMT+08:00).