Implication of three distinct groups of Anopheles lindesayi in Japan by morphological and genetic analyses

Abstract

Anopheles (Anopheles) lindesayi Giles consists of five subspecies. From Japan, only one subspecies, An. l. japonicus Yamada, has been recorded; its geographical populations are morphologically diverse, however, they are regarded as a single subspecies. In this study, we re-evaluated the taxonomic status of An. l. japonicus in Japan and another subspecies, An. l. pleccau distributed in Taiwan, by comparative morphological and molecular analyses based on gene sequences of mitochondrial DNA cytochrome oxidase I (COI) and ribosomal DNA internal transcribed spacer 2 (ITS2). Nucleotide sequence divergence was calculated using the Kimura-two-parameter (K2P) distance model. Phylogenetic trees based on the COI and ITS2 sequences showed three distinct clades: Eastern Japan, Western Japan and, Ryukyus. The sequences of Ryukyus were located the same clade as the sequences of Taiwan. Regarding the COI sequences, the three geographical groups in Japan were genetically well isolated. The following morphological characteristics distinguished the groups: larval seta 1-S, pupal setae 5 through segments IV–VII, and pupal setae 6 on segments IV–VII. Based on these results, it was revealed that An. l. japonicus included three genetically and morphologically distinct groups: two groups of An. l. japonicus and a group in Ryukyus which is a synonym of An. l. pleccau.