The spatial distribution pattern of the daytime-resting populations of adult mosquitoes in the paddy area

Abstract

The spatial distribution pattern of the populations of adult mosquitoes resting in the daytime was estimated by using Morisita's I_δ-index. Mosquitoes were collected once a week in the daytime with a sampling cage at a swamp and adjacent rice fields in the suburbs of Kyoto in 1973 and 1974. I_δ-index was calculated for males, females and the different stages of females (unfed, fed and gravid) as far as possible in Culex pipiens pallens, Cx. tritaeniorhynchus and Anopheles sinensis which were the dominant species at each sampling site. As a result, the greater part of I_δ-indices was larger than unity meaning that the spatial distribution was generally the contagious distribution irrespective of species, sex and stage. It was considered that the contagious distribution might chiefly be caused by the environmental gradient such as the differences in light intensity in the resting places.