Study of mosquito fauna in rice ecosystems around Hanoi, Northern Vietnam

• Published in: Acta tropica Vol. 142; pp. 89 - 95
• Main Authors: Ohba, Shin-ya, Van Soai, Nguyen, Van Anh, Dinh Thi, Nguyen, Yen T., Takagi, Masahiro
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2015
• Subjects: Agriculture; agroecosystems; Animals; Anopheles; aquatic habitat; breeding sites; crop production; Crops, Agricultural; Culex; Culex - physiology; Culex vishnui; Culex vishnui subgroup; dry season; Ecosystem; encephalitis; Encephalitis, Japanese - parasitology; fauna; Hemiptera; Humans; insect larvae; Insect Vectors - physiology; Integrated vector management; irrigation canals; Larva; Mansonia; Micronecta; Mosquito Control; Oryza; Oryza sativa; paddies; Pleidae; ponds; predators; Rain; rice; Seasons; Veliidae; Vietnam; wet season; Wetlands; Vietnam; Vietnam, Hanoi; Japan, Shikoku, Kochi Prefect., Kochi; Culex vishnui subgroup; Agriculture; Integrated vector management; Mosquito control
• ISSN: 0001-706X; 1873-6254; 1873-6254
• DOI: 10.1016/j.actatropica.2014.11.002

•We investigated the mosquito in northern Vietnam during the rainy and dry seasons.•We totally collected 6 Culex, 4 Anopheles, 1 Mansonia, and 1 Mimomyia species.•Cx. tritaeniorhynchus and Cx. vishnui complex were found in all study areas.•High density of mosquito larvae was found during the rainy season.•These findings deepen our understanding of mosquito ecology. Species of the Culex vishnui subgroup, Cx. fuscocephala and Cx. gelidus, which are known Japanese encephalitis (JE) vectors, are distributed in rice agroecosystems in Asian countries. Hence, although ecological studies of rice agroecosystems in northern Vietnam are necessary, very few integrated studies of breeding habitats of mosquitoes, including JE vectors, have been conducted. We carried out a field study and investigated the mosquito fauna in six rice production areas in northern Vietnam during the rainy and dry seasons of 2009. Mosquitoes and potential mosquito predators were collected from aquatic habitats by using larval dippers. We collected 1780 Culex individuals (including 254 Cx. tritaeniorhynchus; 113 Cx. vishnui, 58 Cx. vishnui complex, consisting of Cx. vishnui and Cx. pseudovishnui; 12 Cx. gelidus; 1 Cx. bitaeniorhynchus; and 1 Cx. fuscocephala), 148 Anopheles individuals (including 5 An. vagus), 1 Mansonia annulifera, and 1 Mimomyia chamberlaini during the rainy season. During the dry season, we collected 176 Culex individuals (including 33 Cx. vishnui, 24 Cx. tritaeniorhynchus, 8 Cx. vishnui complex, and 1 Cx. gelidus) and 186 Anopheles individuals (including 9 An. tessellatus, 2 An. kochi, and 2 An. barbumbrosus). We found mosquitoes in all aquatic habitats, namely, rice fields, ditches, ponds, wetlands, irrigation canals, and rice nurseries, and Cx. tritaeniorhynchus and Cx. vishnui complex were found in all the above six areas. Heteroptera such as Micronecta, Veliidae, and Pleidae were abundant and widely distributed in both the seasons. The abundance of mosquito larvae was higher in the rice fields, ditches, and ponds during the rainy season than during the dry season. Cx. tritaeniorhynchus, Cx. vishnui complex, Cx. fuscocephala, and Cx. gelidus were abundant in rice agroecosystems (rice fields, ditches, ponds, and wetlands) in northern Vietnam, and their abundance was high during the rainy season. These findings deepen our understanding of mosquito ecology and strengthen mosquito control strategies to be applied in rice ecosystems Vietnam in the future.