The population distribution and genetic diversity of autogenous Culex pipiens molestus (Diptera: Culicidae) in Taipei and Kaohsiung

• Main Authors: Kai-Di Yu, 游凱迪
• Other Authors: Kun-Hsien Tsai
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/62d2f2

碩士 === 國立臺灣大學 === 環境衛生研究所 === 107 === Culex pipiens molestus is an autogenous (produce their first eggs without a blood meal), hypogenous (develop underground), stenogamous (mate in a confined space) and non-diapause (not affect by photoperiod) mosquito which recognized as an invasive species initially documented in 1996 by Lien et al. and coexisted with common species Cx. quinquefasciatus in our urban city. This species is not only nuisance people’s daily life, but plays a potential role in disease transmission; thus, making it an environmental and public health concern. However, little is known about its distribution and genetic diversity since it has been found two decades later in Taiwan. In this study, Culex samples were collected from the internal of the buildings in Taipei and Kaohsiung from December 2015 to May 2019. The collected samples were initially discriminated based on their morphological features, and a subset of samples was further analyzed molecularly targeting the acetylcholinesterase (Ace) gene. Further, several genes were characterized to evaluate population genetic diversity including Cytochrome oxidase c subunit I (COI), Wolbachia surface protein (wsp), ankyrin domain protein (ank2), and phage WO (orf7, pk1). In total, a pool of Culex mosquitoes was collected in 81 and 30 buildings of Taipei and Kaohsiung respectively. The presence of Cx. p. molestus was 84% (68/81) in Taipei and in 63% (19/30) Kaohsiung. Analyzing the barcode region of mtDNA revealed two haplotype differences (AA, GA) in one substitute site, and all the samples in Kaohsiung were cline to haplotype AA. The Wolbachia-related gene showed identically in all collected population, and was clustered into wPip-IV; however, the phage orf7 sequences analysis showed double (1.6%; 4/253) or triple (83.4%; 211/253) or non-infection (15.0%; 38/253) in Taipei population, contrasted to all triple (70.8%; 51/72) or non-infection (29.2%; 21/72) in Kaohsiung. Crossing experiments showed Cx. p. molestus in Taipei are fully compatible, neither COI nor orf7 gene differences have affected the results. After the survey of Cx. p. molestus population in Taipei and Kaohsiung, Cx. p. molestus was the majority in indoor building mosquitoes. Furthermore, the northern population showed more genetic diversity than in the southern, and the diverse genotypes of the populations were probably driven from multi-introduction.