Effect of larval environment on some life history parameters in anopheles gambiae s.s. (diptera:culicidae))

The effects of larval density, nutrition and cannibalism risk on some life history parameters of Anopheles gambiae larvae were evaluated in the laboratory. Adult body size was inversely correlated with larval density whereas larval mortality and mean age at pupation varied across experiments. When density increased, the secondary sex ratio shifted toward female bias. Effects of different types of nutrition on larval life were compared by providing larvae with algae Chaetophora sp., fish food or both. The fish food generated the highest mortality, longest developmental time and produced smaller adults. Mortality and developmental time was higher with algae diet. With regard to somatic body reserves, algae-fed larvae had more sugar and lipid and full diet mosquitoes had more glycogen and protein reserves. In a separate set of experiments with cannibalism pressure the mortality rate and developmental time decreased but larval activity and body size increased compared to risk-free larvae.