Productivity of Culex tritaeniorhynchus in Rice Fields of West Bengal, India: Correlates of Immature and Adult Features

Background: Surveillance of larval habitats is a part of entomological monitoring to determine the abundance and facilitate vector mosquito management.

Objective: Survey of the rice field habitats was carried out to characterize the productivity of Culex tritaeniorhynchus Giles, 1901 (Diptera: Culicidae), in West Bengal, India. Apart from the numerical abundance, the life history traits of the mosquito were assessed to enhance the information on the fitness of the individuals.

Methods: Mosquito immature were collected following repeated sampling of rice fields during the paddy rice cultivation. The pupal weight (PW), adult body weight (AW) and wing length (WL) of Cx. tritaeniorhynchus and co-occurring mosquitoes were subjected to multivariate statistical analysis and ANOVA. Correlates of environmental factors, abundance and life history traits were validated as predictors of Cx. tritaeniorhynchus productivity.

Results: Four different mosquitoes namely Culex quinquefasciatus, Anopheles annularis, An. subpictus and An. vagus were encountered in varied number along with Cx. tritaenorhynchus, which could be discriminated significantly using the PW, AW and WL as variables. Water depth (r = + 0.349) and plant height (r = - 0.423) appeared to be a significant (P < 0.05) predictor of the productivity of the mosquito Cx. tritaeniorhynchus. Variations in the correlated traits PW, AW and WL of Cx. tritaeniorhynchus corresponded to the time period of paddy rice cultivation substantiated through the ANOVA.

Conclusion: The pupal productivity as well as the correlated traits PW, AW and WL of Cx. tritaeniorhynchus varied with the time period of paddy rice cultivations, paddy plant height and water depth. The correlated variations with productivity calls for inclusion of the life history traits in entomological monitoring of Cx. tritaeniorhynchus to appraise the fitness and the population abundance with higher precision.