Host-seeking and blood-feeding behavior of Aedes albopictus (Diptera: Culicidae) exposed to vapors of geraniol, citral, citronellal, eugenol, or anisaldehyde.

The changes of the host-seeking and blood-feeding behavior of Aedes albopictus (Skuse) (Diptera: Culicidae) surviving in a space containing vapors of the spatial repellents geraniol, eugenol, citral, anisaldehyde, or citronellal were evaluated using an arm-in-cage test and a bioassay of bloodmeals on a shaved mouse. The mosquitoes surviving concentrations of geraniol, citral, eugenol, or anisaldehyde at 0.013, 0.025, 0.050, 0.100, and 0.250 microg/cm3 for 24 and 48 h all showed different degrees of reduction in host-seeking ability. After 48 h of exposure to 0.250 microg/cm3 geraniol, almost 100% of the mosquitoes lost their host-seeking ability. The next most potent spatial repellent, anisaldehyde, stopped host seeking by > 85.5%. Citronellal did not result in a significant reduction in the host-seeking ability at any concentration level after either 24 or 48 h of treatment. We also found that reduction of host-seeking ability recovered after various times. The longest recovery time (144 h) was observed for geraniol after 24 h at 0.250 microg/cm3. In the study, geraniol, eugenol, and citral all significantly affected the activation and orientation stages of the blood-feeding behavior. However, only anisaldehyde significantly interrupted the normal blood-feeding of mosquitoes in all stages of behavior. These initial laboratory results clearly showed that anisaldehyde and geraniol could be promising spatial repellents against Ae. albopictus that they could play a major role in new repellent technology.