Behavioral responses of Aedes aegypti (Diptera: Culicidae) exposed to deltamethrin and possible implications for disease control.
Behavioral responses of nine Aedes aegypti (L.) strains, six from recent field collections and three from the long-established laboratory colonies, were tested under laboratory-controlled conditions by using an excito-repellency test system. All nine strains showed significant behavioral escape responses when exposed to deltamethrin at the standard field dose (0.02 g/m2), regardless of background insecticide susceptibility status (susceptible or tolerant/resistant). Insecticide contact irritancy played a predominate role in overall female mosquito escape responses, whereas noncontact repellency was not observed at levels significantly different from paired noncontact control tests (P > 0.01). Among the six field populations, the Jakarta (Indonesia) Toba (north Sumatra), and Bangkok female mosquitoes showed rapid exit (>78%) during 30 min of direct contact with insecticide-treated surfaces, whereas the other three strains demonstrated only moderate escape responses (32-56%) from the chambers. Moderate escape responses during direct insecticidal contact also were observed in the three laboratory test populations (44- 60%). Higher percentage of mortality was observed from laboratory strains (8-33%) that failed to escape compared with nonescape females of field strains (2-16%), possibly a reflection of background deltamethrin susceptibility status. We conclude that contact irritancy is a major behavioral response of Ae. aegypti when exposed directly to deltamethrin and that rapid flight escape from areas exposed to space sprays or surfaces treated with residual pyrethroids could have a significant impact on the effectiveness of adult mosquito control and disease transmission reduction measures.
Kongmee
Monthathip
M
Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand.
Prabaripai
Atchariya
A
Akratanakul
Pongthep
P
Bangs
Michael J
MJ
Chareonviriyaphap
Theeraphap
T
D000330:Aedes / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D000830:Animals, Laboratory; D006801:Humans; D007306:Insecticides / Q000633:toxicity*; D008288:Malaria / Q000517:prevention & control*; D009032:Mosquito Control / Q000379:methods*; D009570:Nitriles; D011722:Pyrethrins / Q000633:toxicity*
D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin