Effects of a Water Level Fluctuations on Littoral Aquatic Insects in an Agricultural Irrigation Pond

To evaluate the effects of water level fluctuations on littoral aquatic insects in an agricultural irrigation pond, I surveyed species and abundance of aquatic insects and environmental factors, such as water depth, length of surface-exposure, and abundance of aquatic plants, at seven plots (50 by 50 cm) on the littoral zone of the pond in 2008. Five species of odonate larvae (dragonflies and damselflies) and eight species of adult aquatic beetles were collected during the survey period. Regression analysis was executed to determine environmental factors which affect for species richness and abundance of odonate larvae and adult aquatic beetles. As the results, the difference of the length of surface-exposure did not necessarily affect inhabitant of the littoral aquatic insects.