Journal of Entomological Research

Fluctuating asymmetry (FA) of Hydropsyche doctersi (Trichoptera: Hydropsychidae) and its relationship with physico-chemical parameters of four rivers, Kurau River and Ara River in Perak while Kob River and Sedim River in Kedah, Malaysia were studied. All investigated rivers experienced good water quality (Class II) according to water quality index (WQI), although the rivers were surrounded by different land uses. However, high values of BOD, COD and TSS of Kob River indicated that the river was highly polluted. The influence of several physicochemical parameters on H. doctersi anatomical structures such as 1^st tarsal claw length, ₁st tarsal length, 1^st tibial length, 1^st tibial width, 2^nd tibial length, 2^nd tibial width, 2^nd femur length, 3^rd tibial length, 3^rd tibial width, 3^rd femur length, 3^rd trochanter length, mesonotum length and anal claw length were also investigated. However, only four structures (2^nd tibial length, TBL and 3rd tibial width, TBW) exhibited FA in H. doctersi samples from the rivers and were further analyzed. Results revealed that the greatest numbers of traits exhibited FA was recorded at Ara River with eight traits and the greatest FA11 was recorded in third femur length, meanwhile only three traits exhibited FA in Kurau River. In 3^rd TBW, AbsFA and FA index showed correlation with nitrate concentration in the rivers. The FA incidence was also reported in the 1st TBL based on correlation of AbsFA with temperature, TDS and orthophosphate. As a conclusion, FA occurrence at Hydropsyche doctersi has proved that river pollution contributed to deformities among the aquatic organisms.