Effects of Temperature and Nutrition during the Larval Period on Life History Traits in an Invasive Malaria Vector Anopheles stephensi

Abstract

Anopheles stephensi is an Asian and Middle Eastern malaria vector, and it has recently spread to the African continent. It is needed to measure how the malaria parasite infection in A. stephensi is influenced by environmental factors to predict its expansion in a new environment. Effects of temperature and food conditions during larval periods on larval mortality, larval period, female wing size, egg production, egg size, adult longevity, and malaria infection rate were studied using a laboratory strain. Larval survival and female wing size were generally reduced when reared at higher temperatures and with a low food supply during the larval period. Egg production was not significantly affected by temperature during the larval period. Egg size was generally smaller in females reared at higher temperatures during the larval period. The infection rate of mosquitoes that fed on blood from malaria-infected mice was not affected by rearing temperature or food conditions during the larval period. Higher temperatures may reduce infection. A. stephensi; however, larger individuals can still be infective. We suggest that routinely recording the body size of adults in field surveys is effective in finding productive larval breeding sites and in predicting malaria risk.

Keywords: Plasmodium; infection; invasive species; life history traits; longevity.

Figure 1

Survival female mosquitoes that were allowed to take blood meals from infected mice once (A) and twice (B), 14 and 20 (or 22) days after the first blood meal. Open circle (reared at 27 °C under high food supply during the larval period); open square (reared at 27 °C under low food supply); closed circle (at 32 °C under high food supply); closed square (at 32 °C under low food supply). The arrow indicates the second blood meal.