Wolbachia infection and genotyping in Aedes albopictus

Objective To investigate the infection and genotypes of Wolbachia in Aedes albopictus.

Methods Adult and larval samples of Aedes albopictus werecollected from different residential and wild areas from 2020 to 2021， Wolbachia surface protein （wsp） gene was amplified and genotyped for wAlbA and wAlbB by PCR， and sequenced for phylogenetic analysis. The difference of detection rate among different habitats， male and female adult mosquitoes， adult and larvae was compared by χ² analysis.

Results The detection rate of Wolbachia in adult and larvae of Aedes albopictus were 43.5% （77/177） and 70.4% （190/270）， respectively， with a statistically significant difference （χ²=32.086，P<0.001）， and wAlbA and wAlbB were mainly detected together. The detection rate of Wolbachia in female and male Aedes albopictus were 50.7% （76/150） and 3.7% （1/27）， respectively， with a statistically significant difference（χ²=20.533，P<0.001）. The detection rate of adult Aedes albopictus in Songjiang wild area， residential area and Hongkou residential area were 91.7% （55/60）， 18.8% （22/117） and 41.7% （30/72）， respectively， with a statistically significant difference （χ²=54.322，P<0.001）. Genotyping and phylogenetic analysis showed that adult and larvae of Aedes albopictus infected with Wolbachia were mainly wAlb A and wAlb B. In addition， some sequences formed clades independently， and the genetic distance from other sequences was relatively large.

Conclusion Infection of Wolbachia in Aedes albopictus is relatively common in Songjiang District. The main genotypes are wAlb A and wAlb B and there may be other subtypes， which are worthy of further exploration and research.