蚊成虫の行動に及ぼす殺虫剤の影響に関する室内試験

Abstract

In order to study the effects of insecticides on the behaviour of female mosquitoes under the laboratory conditions, a series of cage tests were carried out. The apparatus was composed of two wire-cages (30×30×30cm each); one served as a release cage of avid mosquitoes and the other served as a mouse-baited cage. The wide-mesh net was impregnated with the candidate insecticide at different doses and interposed between the two cages, but the mosquitoes were able to pass through the mesh. The mosquitoes were introduced at 3pm and recovered 19hrs later. The result showed that phenothrin treated net had marked effects on the behaviour of Anopheles stephensi. There was a high level of inhibition in entering the bait-cage and in feeding blood. Also fed mosquitoes were driven out of the bait-cage by the irritant action of the insecticide. However, a high mortality masked those responses at a dose higher than 0.64g/m^2. It was also demonstrated that the avid mosquitoes, which were introduced into the bait-cage, moved away to the other cage without feeding. In the case of Culex pipiens pallens, deterrent effects in the entering behaviour were almost negligible. Feeding in Aedes albopictus was less inhibited than in the other mosquitoes. Reduction of entry and feeding by the fenitrothion treated net was due to high mortality of mosquitoes. The inhibition of feeding was observed in Cx. pipiens pallens which shows high resistance to this insecticide, though they entered the bait-cage. This apparatus seems to be practical for assessing the behavioural reaction to insecticides of various species of mosquitoes.