PESTICIDE AVOIDANCE-BEHAVIOR IN ANOPHELES-ALBIMANUS, A MALARIA VECTORIN THE AMERICA

The behavioral responses of 4 populations of Anopheles albimanus femal es to DDT, permethrin, and deltamethrin were characterized in excite-r epellency tests. One test population (ST) from Fl Salvador has been ma intained as a colony for 20 years. A second population (ES) from Guate mala was colonized in 1992. Third and fourth populations consisted of field-caught specimens from Toledo District (TO) of southern Belize in 1994 and Corozal District (GO) of northern Belize, respectively. Fema les of ES, TO, and CO populations rapidly escaped from direct contact with treated surfaces for each of the 3 insecticides. Similarities in escape responses of insecticide-resistant (ES) versus insecticide-susc eptible populations (TO, CO) suggest that there is no relationship bet ween physiological and behavioral responses of An. albimanus populatio ns to DDT, permethrin, and deltamethrin. Females from all but the ST c olony escaped in greater numbers from chambers without direct contact with treated surfaces than from control chambers (P < 0.05). Few femal es from the ST colony escaped from test chambers, regardless of which insecticide was used or whether contact was allowed, indicating that t he ST colony has lost its capability to respond to insecticides. Repel lent responses were significant; but they were not pronounced in 30-mi n exposures, and they were very pronounced in 4-h exposures. We conclu de that irritant and repellent responses of malaria vectors to insecti cides are important components of malaria control operations.