The Effects of Pre - exposure to DEET on the Downstream Blood - Feeding Behaviors of 9 Aedes aegypti Mosquitoes

26 Mosquito behavior is heavily influenced by the chemical molecules in the environment. 27 Modifying insect behavior by harnessing this knowledge to reduce vector-host contact is a 28 powerful method for disease prevention. N,N-Diethyl-meta-toluamide (DEET) is the most 29 widely used insect repellent on the market and an excellent example of a chemical that has been 30 used to modify insect behavior for disease prevention. However, genetic insensitivity and 31 habituation in Aedes aegypti (L.) mosquitoes after pre-exposure to DEET have been reported. In 32 this study, we investigated the effect of pre-exposure to DEET on the downstream blood-feeding 33 behavior of Ae. aegypti mosquitoes and the duration of the effect. We exposed mosquitoes to 34 four different DEET concentrations: 0.10, 0.12, 0.14, and 0.16% for 10 min then allowed the 35 mosquitoes to blood-feed on an artificial blood-feeding system either immediately or after being 36 held for 1, 3, 6, or 24 h following DEET exposure. We found that pre-exposing Ae. aegypti 37 mosquitoes to 0.14 or 0.16% DEET lowered their blood engorgement level, but did not alter their 38 landing and probing behavior when compared to the control test populations. The reduction in 39 complete blood-feeding was observed at all time periods tested, but was only statistically 40 significant at 3 and 6 h after the pre-exposure process. Future studies analyzing the effect of this 41 behavior using arbovirus-infected mosquitoes are needed to address the concern of potentially 42 increased vectorial capacity. 43