Breeding habitats & seasonal variation in the larval density of Aedes aegypti (L) & Ae. albopictus (Skuse) in an urban garden in Calcutta city

A longitudinal study on the breeding habitats and variation in the relative larval density of Ae. aegypti and Ae. I albopictus was conducted in an urban garden in Calcutta city. The observations of the study, during October 1995 to September 1996 revealed that both the species showed preference for breeding in earthen, and cement pots, plant pots, chowbachhas and molluscan shells. Ae. albopictus larvae were also found in accumulations of water in bamboo stumps and tree holes. The container positivity and relative larval density of both species was highest during monsoon (June 1996 - September 1996) and lowest during summer (February 1996 - May 1996). The seasonal variation in container index (CI) of each species was statistically significant (P<0.05) and showed a positive correlation with rainfall, the seasonal variation in the larval density of both Ae. aegypti and Ae. albopictus in permanent breeding sites was however not statistically significant, indicating that the CI and relative larval density of the two species was unaffected by temperature and humidity. The variation between the larval density and their CI in the same season was not significant, suggesting a perfect adaptation of Ae. aegypti, an urban, and Ae. albopictus, a sylvatic species, to more or less similar aquatic biotypes in an urban garden.