Influence of body size and age of Aedes albopictus on human host attack rates and the repellency of deet.

Human host attack rates and the repellency of deet (25% in ethanol) to nulliparous Aedes albopictus in the laboratory were significantly influenced (P = 0.05) by mosquito age and body size and by the interaction of age and body size. Host attack rates were higher for 20-day- (24.5%) and 15-day-old females (22.9%) than for 10- (15.1%) and 5-day-old females (11.0%), regardless of body size, and for large females (22.2%) compared with small females (16.6%), regardless of mosquito age. Deet on human skin repelled small-bodied females longer (3.87 h) than large females (2.31 h); 15-day-old females were repelled longer (3.75 h) than 5- (2.33 h), 10- (3.08 h), or 20-day-old females (3.07 h), regardless of body size. Host attack rates and deet repellency among 15-day-old parous and 15-day-old nulliparous large- and small-bodied female Ae. albopictus were similar but deet repellency was less (by approximately 2 h) against large females compared with small-bodied females.