Abstract
Species composition of aquatic insect in the swimming pool of 32 schools in Tokyo and Chiba prefectures was studied from 2007 to 2008. As a result of TWINSPAN analysis, stands were primarily classified into 2 groups as Tokyo and Chiba. Rhantus pulverosus, Hydaticus grammicus, Ranatra chinensis, and Crocothemis servilia mariannae were not observed at the swimming pools in Tokyo. Major environmental factors of species composition were considered to be the ratio of paddy field in the district and the presence of trees around the pool. The amount of fallen leaves in the pools affected the species population of aquatic insects.
