U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska

 

Date of this Version

2007

Citation

Experimental Parasitology 116 (2007) 201–204; doi:10.1016/j.exppara.2006.12.011

Abstract

This study determined the effects of contact with DEET on guinea pig skin on mortality, probing time, blood feeding rate, engorgement time, and fecundity responses in female Anopheles quadrimaculatus Say. Exposure, in this manner, to 10% DEET (in ethanol) for 5min, resulted in 98% mortality in mosquitoes after 24 h. The median probing time (PT50) required by females, when exposed to 0.1%, 1.0%, and 10% DEET, was significantly (P< 0.0001) longer (12.5, 12.1, and 19.1 s, respectively) than the 6.8 s required by females to probe ethanol-treated skin (control). Similarly, mean blood feeding rates in populations of females exposed to 1.0% DEET for ≤5min (14.4%) was 6x lower (P <0.001) (85.5%) than in females exposed to ethanol-treated skin, whereas the mean engorgement time on skin treated with 1.0% DEET (66.3 s) was significantly shorter (P<0.0001) than for females feeding on the control guinea pigs (105.9 s). The mean number of mature oöcytes per female (fecundity) in treatment (1.0% DEET) and control mosquitoes was not significantly different. The responses to DEET observed in this study suggest that repeated exposure of female A. quadrimaculatus populations to this repellent, in laboratory bioassays, could result in confounding of toxicant and repellent effects and inaccurate estimates of DEET repellency.

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