The Effects of Pre-Exposure to DEET on the Downstream Blood-Feeding Behaviors of Aedes aegypti Mosquitoes

Abstract : Mosquito behavior is heavily influenced by the chemical molecules in the environment. Modifying insect behavior by harnessing this knowledge to reduce vector-host contact is a powerful method for disease prevention. N,N-Diethyl-meta-toluamide (DEET) is the most widely used insect repellent on the market and an excellent example of a chemical that has been used to modify insect behavior for disease prevention. However, genetic insensitivity and habituation in Aedes aegypti (L.) mosquitoes after pre-exposure to DEET have been reported. In this study, we investigated the effect of pre-exposure to DEET on the downstream blood-feeding behavior of Ae. aegypti mosquitoes and the duration of the effect. We exposed mosquitoes to four different DEET concentrations: 0.10, 0.12, 0.14, and 0.16 for 10 min then allowed the mosquitoes to blood-feed on an artificial blood-feeding system either immediately or after being held for 1, 3, 6, or 24 h following DEET exposure. We found that pre-exposing Ae. aegypti mosquitoes to 0.14 or 0.16 DEET lowered their blood engorgement level, but did not alter their landing and probing behavior when compared to the control test populations. The reduction in complete blood-feeding was observed at all time periods tested, but was only statistically significant at 3 and 6 h after the pre-exposure process. Future studies analyzing the effect of this behavior using arbovirus-infected mosquitoes are needed to address the concern of potentially increased vectorial capacity.