Integrated systematics of Anopheles subpictus (Diptera: Culicidae) in the Oriental Region, with emphasis on forms in Thailand and Sulawesi, Indonesia

Abstract

© 2020 Elsevier B.V. The Anopheles subpictus complex consists of four species informally designated, based on fixed inversions of polytene chromosomes and morphology, as species A, B, C and D in India. However, recent studies revealed the presence of only species A and B in Sri Lanka. Little is known about the specific identity of the taxon in other countries in Asia. This paper reports the results of a molecular and morphological study of An. subpictus in Thailand and South Sulawesi, Indonesia. The maxillary palpi of most females from Thailand have the apical pale band longer than the subapical dark band, seta 7-I of pupae branched and short, and eggs with 18–25 float ridges. These characters do not agree with those described for species A, B, C and D in India. The females of An. subpictus from South Sulawesi usually have the subapical dark band of the maxillary palpus equal in length to the apical pale band. Phylogenetic analyses of sequences of the internal transcribed spacer 2 (ITS2) region of rDNA and the cytochrome c oxidase subunit I (COI) gene of mtDNA of specimens from Thailand, and South Sulawesi, and from various localities in GenBank, were conducted. ITS2 sequences of specimens from all localities in Thailand were identical, except for a small divergence in specimen from Phang Nga Province. Three distinct COI clades were detected in specimens from Chiang Mai Province in northern Thailand. However, crossing experiments between the three clades revealed no genetic incompatibility, suggesting that they were conspecific. ITS2 and COI sequences of most specimens from Thailand fell in clades other than those of An. subpictus species A and B and An. subpictus from Indonesia (East Nusa Tenggara, Java, South Sulawesi) and the Philippines. ITS2 sequences from South Sulawesi and East Nusa Tenggara were very similar, and fell in a clade consisting of specimen from Phang Nga in southern Thailand and sequences of some specimens from Cambodia and Vietnam, but their COI sequences were distinct. DNA sequences and morphological differences suggest the presence of two species within An. subpictus in Thailand, and more than one species in Indonesia.