*Sakakibara, Y.（Grad. Sch. Agric., Shinshu Univ.）, Okubo, K., Oishi, Y. (Shinshu Univ.)

Paddy field is a typical secondary natural environment. And the environment is a valuable habitat for freshwater wetland species. So, recently, it is a serious problem that many aquatic insect species has decreased and exterminated because of various changes at paddy field area. The purpose of this study is to understand the relationship between the aquatic insect communities and the environmental conditions at paddy field areas in different location of the southern part of Nagano Prefecture in order to suggest concrete conservation measures. The aquatic insect community and environmental condition surveys were carried out in the rice paddy field areas at different location in 5 areas from May to September in 2011. Aquatic insects were captured in the paddies within 2 meters from the edge which used D-frame spoon net. The taxsomic groups were mainly Coleoptera, Hemiptera, Odonata , Lepidoptera, Ephemeroptera, Plecoptera, Trichoptera, and Diptera. The number of appearance species was 31, and the total populations was 5362. Cybister brevis, Hydrophilus acuminatus, Plecoptera, Enochrus japonicus, Syrphidae, and Simuliidae were appeared mainly at mountainous areas. On the one hand, Enochrus simulans and Haliplus sp. were appeared especially at urbanized areas.