Natural survivorship of immature stages of Culex vishnui (Diptera: Culicidae) complex, vectors of Japanese encephalitis virus, in rice fields in southern India.
The development and survival of immatures of Culex vishnui (Diptera: Culicidae) complex, vectors of Japanese encephalitis virus, were studied in transplanted rice, Oryza savita L., fields during three crop growing seasons. The total duration of development from the first instar to adult emergence varied from 6 to 8 d. Survival rate estimates ranged from 0.003 to 0.524, but they generally were <0.1. Unusually high survival rates (0.192-0.524) were observed in summer and long-term monsoon crop seasons during 1993. A multiple regression method using backward elimination was used to analyze the factors responsible for these variations. The model identified nine parameters related with survival rates that explained 99% of the variance. Area of water surface and hardness were negatively related, whereas green algae, notonectid adults, anisopterans, dytiscids, salinity, water depth, and dissolved oxygen were positively associated with immature survival.
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Centre for Research in Medical Entomology (Indian Council of Medical Research), No. 4 Sarojini Street, Chinna Chokkikulam, Madurai 625 002., Tamil Nadu State, India.
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Rajendran
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D000818:Animals; D018556:Crops, Agricultural; D003465:Culex / Q000145:classification / Q000254:growth & development* / Q000821:virology; D004664:Encephalitis Virus, Japanese; D004672:Encephalitis, Japanese / Q000635:transmission; D007194:India / Q000453:epidemiology; D007303:Insect Vectors / Q000254:growth & development* / Q000821:virology; D007814:Larva / Q000254:growth & development; D012275:Oryza; D011679:Pupa / Q000254:growth & development; D012044:Regression Analysis; D012621:Seasons; D015996:Survival Rate; D013997:Time Factors; D014867:Water
D014867:Water