The highest number of aquatic insects was found at the first sampling site (MK1-Golden Triangle) because there were several types of micro-habitats with aquatic plants, gravel and sand. On the other hand, the lowest number was found from MK10 (Mekong river, Kaeng Kabou, Wan Yai, Mukdahan) which might be the result of human impact such as agriculture and livestock. Moreover, the substrate of this site was big boulders and bed rock, which is not suitable for aquatic insect survival (Table 2).