Abstract
Weekly investigations on oviposition activity of mosquitoes were carried out by an ovitrap method in four study areas in Kamakura City from May to December in 1971. The percentages of ovitraps found positive showed a sharp increase at week 27. A high level of ovitrap positivity was observed during weeks 31 through 35. Oviposition activity decreased significantly by week 36. The late-season peak appeared in these areas during weeks 38 and 39. A total number of the eggs deposited in ovitraps was recorded as 10,841 for C area, 8,653 for B area, 7,813 for D area and 6,680 for A area respectively. The sensitivity of the ovitrap was closely related with its placement. The total numbers of the eggs of one trap which was placed on the same site ranged from 14 to 1,074 (average 340) during 28 weeks. The following 8 species were found : Acdes albopictus, Tripteroides bambusa, Uranotaenia bimaculata, Aedes japonicus, Aedes nipponicus, Culex tritaeniorhynchus, Armigeres subalbatus and Aedes flavopictus. Aedes albopictus was the dominant species (73.9 percent) followed by Tripteroides bambusa (13.1 percent) and Uranotaenia bimaculata (9.1 percent). The collections of the four study areas indicated that the species compositions were resembled each other but the relative abundances were different. In A area the percentage of Aedes albopictus was greater than in B area. It appeared that suitable oviposition sites by Aedes albopictus increased with enlargement of the housing area. Ovitraps proved to be a better method for detecting of Aedes albopictus and other small-container breeders.
