草地の晝間潜伏蚊類群集の生態学的研究 : 第 1 報群集構造の動態

Abstract

The result of survey conducted during the period from July to October 1956 on the composition and seasonal succession of a community of adult mosquitoes resting in the daytime in the grass of Chikugo River-bed at Mamezu, Saga Prefecture is given in the present paper. The method for sampling was to sweep the grass by a net for five minutes and the number of mosquitoes collected in the net was counted. During the period of survey, only five species of mosquitoes, Anopheles sinensis Wiedmann, Culex tritaeniorhynchus Giles, Culex pipiens Linnaeus, Culex vishnui Theobald and Culex bitaeniorhynchus Giles were recognized in the grass of the river-bed. The seasonal succession of the mosquito community resting in the daytime is given in Fig.2. In the community A. sinensis occupied of majority of the species, C. tritaeniorhynchus was the next abundant species, and the other species were found in far lesser numbers. Seasonal changes of A. sinensis and C. tritaeniorhynchus are given in Fig.4. Apparently C. tritaenicrhynchus was the dominant species during July in the community, whereas A. sinensis was most prevalent in later period. Although the total number of C. tritaeniorhynchus far exceeded that of A. sinensis in this area, A. sinensis was found in largest numbers in the grass. This indicates that the grass provided the best resting habitat in the daytime for A. sinensis. An analysis of a population of A. sinensis in such a habitat showed that females are more prevalent individuals than males and engorged females are more numerous than unfed ones.