Aedes aegypti disregard humidity-related conditions with adequate nutrition.

Weather variations have clear associations with the epidemiology of dengue fever and populations of Aedes aegypti mosquitoes. Data on humidity associations, however, lags with respect to its effect on host-biting, nectar-seeking and survival. This experimental study on Ae. aegypti, sourced from the arid tropics, investigated the effect of low and high relative humidity and diet in relation to host-biting, temporal variations in feeding frequency, and mosquito mortality. In each environmental setting, 10 replicates, containing one male and five female mosquitoes, were challenged with different nutritional sources every six hours over 12 days. Results showed that host-biting did not diminish in low humidity and was six times higher than expected. Sucrose feeding was observed to significantly moderate host-biting and water alone was inadequate for survival. The high host-biting rates help to explain the intensity of dengue epidemics, while the ability of the mosquito to disregard adverse humidity-related conditions helps to explain how dengue epidemics in arid tropical regions can be just as devastating as those in the wet tropics.