Abstract
We studied the mandible shapes of aquatic insects, and analyzed correlations between the wet body weight and the size of mandibles and other parts of six orders, 15 families commonly found in the Takami and Shigou Rivers in Higashiyoshino, Nara Prefecture. Highly significant correlations between the size of mandible and wet body weight of insects were obtained in all families studied. Since the mandibles of aquatic insects usually remain in the feces of the birds and the stomachs of fishes, and are easily identified by family name, the regression lines obtained in this study would be useful in estimating the amount of prey taken by animals.
