First report on high-degree endophilism in Culex tritaeniorhynchus (Diptera: Culicidae) in an area endemic for Japanese encephalitis.

An unusually high occurrence of Culex tritaeniorhynchus Giles resting indoors during daytime was observed in a Japanese encephalitis (JE) endemic area, Bellary district, Karnataka, India. Cx. tritaeniorhynchus, the primary vector of JE in this area, was the dominant species collected, and its abundance showed two peaks corresponding to rice crops in the district. More specimens (n = 20,966) were found resting in indoor habitats than in outdoor vegetation (n = 383), despite the availability of outdoor resting sites. This resting behavior is opposite to the Cx. tritaeniorhynchus behavior reported in the majority of JE-affected areas, where this species was captured in small numbers from indoor resting sites. Increased endophilic resting behavior indicates that indoor residual insecticides may provide an effective control method in this area.