The Influence of Insecticide Resistance, Age, Sex, and Blood Feeding Frequency on Thermal Tolerance of Wild and Laboratory Phenotypes of Anopheles Funestus (diptera: Culicidae)

Resistance to insecticides is a global phenomenon and is increasing at an unprecedented rate. How resistant and susceptible strains of malaria vectors might differ in terms of life history and basic biology is often overlooked, despite the potential importance of such information in light of changing climates. Here, we investigated the upper thermal limits (ULT50) of wild and laboratory strains of Anopheles funestus Giles mosquitoes, including resistance status, sex, age, and blood feeding status as potential factors influencing ULT50. No significant differences in ULT50 were observed between strains displaying different resistance patterns, nor was there a significant difference between wild and laboratory strains. In some instances, strains showed a senescence response, displaying decreased ULT50 with an increase in age, and differences between males and females (females displaying higher ULT50 than males). Blood feeding did not seem to influence ULT50 in any way. For An. funestus, it seems evident that there is no cost to resistance despite what is displayed in other anopheline species. This could have significant impacts for vector control, with resistant populations of An. funestus performing just as well, if not better, than susceptible strains, especially under changing environmental conditions such as those expected to occur with climate change.