Climatic variation is a key driver of genetic differentiation and phenotypic traits evolution, and local adaptation to temperature is expected in widespread species. We investigated phenotypic and genomic changes in the native range of the Asian tiger mosquito, Aedes albopictus. We first refine the phylogeographic structure based on genome-wide regions (1,901 ddRAD SNPs) from 41 populations. We then explore the patterns of cold adaptation using phenotypic traits measured in common garden (wing size and cold tolerance) and genotype–temperature associations at targeted candidate regions (51,706 exon capture SNPs) from 9 populations. We confirm the existence of three evolutionary lineages including clades A (Malaysia, Thailand, Cambodia, and Laos), B (China and Okinawa), and C (South Korea and Japan). We identified temperature-associated differentiation in fifteen out of 221 candidate regions but none in ddRAD regions, supporting the role of directional selection in detected genes. These include genes involved in lipid metabolism and a circadian clock gene. Most outlier SNPs are differently fixed between clades A and C, while clade B has an intermediate pattern. Females are larger at higher latitude yet produce no more eggs, which might favor the storage of energetic reserves in colder climate. Non-diapausing eggs from temperate populations survive better to cold exposure than those from tropical populations, suggesting they are protected from freezing damages but this cold tolerance has a fitness cost in terms of egg viability. Altogether, our results provide strong evidence for the thermal adaptation of A. albopictus across its wide temperature range.

Background Aedes mosquitoes are important invasive species contributing to the spread of chikungunya, dengue fever, yellow fever, zika virus, and other dangerous vector-borne diseases. Aedes albopictus is native to southeast Asia, with rapid expansion due to human activity, showing a wide distribution in the Korean peninsula. Aedes flavopictus is considered to be native to East Asia, with a broad distribution in the region, including the Korean peninsula. A better understanding of the genetic diversity of these species is critical for establishing strategies for disease prevention and vector control. Methods We obtained DNA from 148 specimens of Ae. albopictus and 166 specimens of Ae. flavopictus in Korea, and amplified two mitochondrial genes (COI and ND5) to compare the genetic diversity and structure of the two species. Results We obtained a 658-bp sequence of COI and a 423-bp sequence of ND5 from both mosquito species. We found low diversity and a nonsignificant population genetic structure in Ae. albopictus, and high diversity and a nonsignificant structure in Ae. flavopictus for these two mitochondrial genes. Aedes albopictus had fewer haplotypes with respect to the number of individuals, and a slight mismatch distribution was confirmed. By contrast, Ae. flavopictus had a large number of haplotypes compared with the number of individuals, and a large unimodal-type mismatch distribution was confirmed. Although the genetic structure of both species was nonsignificant, Ae. flavopictus exhibited higher genetic diversity than Ae. albopictus. Conclusions Aedes albopictus appears to be an introduced species, whereas Ae. flavopictus is endemic to the Korean peninsula, and the difference in genetic diversity between the two species is related to their adaptability and introduction history. Further studies on the genetic structure and diversity of these mosquitos will provide useful data for vector control.

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In this study, we first determined the mitochondrial genome sequence of Aedes koreicus collected in South Korea. Its mitochondrial genome is 15,840 bp in length and consists of 13 protein-coding genes, 22 transfer-RNA genes, 2 ribosomal-RNA genes, and a non-coding A þ T rich region. The overall base composition in the heavy strand was as follows: A, 40.1%; G, 8.7%; C, 13.6%; T, 37.5%; and the G þ C content was 22.4%. Phylogenetic analysis revealed that Aedes spp. form a monophyletic group.

The superfamily Gonodactyloidea is polyphyletic because of Hemisquillidae, but to date, mitochondrial genome of that family does not exist. As valuable data that can be compared in the future with that family within this superfamily, we report the first complete mitochondrial genome sequence of Taku spinosocarinatus of the family Takuidae. The mitochondrial genome is 15,960 bp in length and consists of 13 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes, and a non-coding A þ T rich region. The overall base composition in the heavy strand was as follows: A: 34.2%, G: 13.4%, C: 19.8%, and T: 32.6%, with a G þ C content of 33.2%. Phylogenetic analysis revealed that this species was most closely related to Gonodactylus chiragra of Gonodactylidae, registered with NCBI to date. The result of this study will enable additional comparisons between families in the future.