Studies on a collecting method of mosquitoes by dry ice and a mosquito net

Abstract

To investigate the usefullness of the carbon-dioxide for collecting mosquitoes in field, the mosquito bet nets in which dry-ice was placed were set in the suburbs of Tokyo in summer season of 1961. In one case, up to 5000 female mosquitoes, consisting mainly of Culex tritaeniorhynchus and partly of C. pipiens and Anopheles spp., were collected in a net. Much more mosquitoes were collected by the dry ice trap than by the animal trap using chicken or goat, or by light trap. Dry ice trap adopted in the present study was proved to be highly effective result for collecting the mosquitoes. Diurnal change of prevalence of mosquitoes was also studied using the dry ice trap. The invading number of mosquitoes, both C. tritaeniorhynchus and C. pipiens, appeared to become the peak from 7 : 00 to 8 : 00p.m., and the invasion lasted till 4 : 00 or 5 : 00a.m. in the next morning.