Assemblage of aquatic H eteroptera ( G erromorpha and N epomorpha) in relation to microhabitats in the P hong R iver, N ortheast T hailand

In this study, we explored the composition and assemblage structure of aquatic H eteroptera from 15 sampling sites along the P hong R iver, T hailand, during the rainy ( J uly 2011), cool ( D ecember 2011) and hot ( M arch– A pril 2012) seasons. A total of 8399 individuals, belonging to 54 species and 12 families of aquatic H eteroptera were recorded. The K ruskal– W allis test indicated significant difference in total number of species and total number of individuals of aquatic H eteroptera among microhabitat types ( P < 0.05). Stepwise multiple regression and canonical correspondence analysis ( CCA ) ordination show that characteristics of microhabitats including percentage of gravel, percentage of aquatic macrophytes covering the water surface and percentage of shading from riparian vegetation determine aquatic H eteroptera assemblage structures. From this study, microhabitats have more effect on aquatic H eteroptera than water pollution.