2016 Volume 21 Issue 2 Pages 227-235
The relationship between structural differences in irrigated rice fields (with or without open channels) and the aquatic insect fauna (Coleoptera and Hemiptera) was examined in southwestern Ehime Prefecture during the cultivation period to accumulate basic knowledge for conserving aquatic insects. Comparison of the average number of aquatic insects collected from rice fields and from open channels showed that there were more individuals in open channels than in rice fields without open channels. Rhantus suturalis, Hydaticus grammicus, Enochrus simulans, Sternolophus rufipes, and Berosus punctipennis were abundant in paddies, where these five species usually breed. Peltodytes intermedius, Haliplus sharpi, and Noterus japonicus were abundant in open channels. It is thought that P. intermedius and H. sharpi gather in open channels, which are rich in the algae they feed on. N. japonicus breeds in water and is thought to select open channels instead of ponds or marshes in areas where the dry period is short.