Mentum deformities in chironomidae (Diptera,Insecta) as indicator of environmental perturbation in freshwater habitats

Deformities in the mouthparts of chironomidae larvae,particularly of the teeth on the mentum,have been proposed as a bioindicator of sediment quality and environmental stress. the chironomidae larvae were collected in the six-ditch canalization in kasetsart university,kamphaeng saen campus,nakhon pathom province over a period of six months between october 2016 to march 2017. three replicates of sampling by aquatic d-frame dip net were used at sampling sites. a total of 1,868 chironomidae larvae,representing 2 subfamilies,chironominae and tanypodinae,were screened for mentum deformities. the observation under the stereomicroscope showed the typical mentum teeth deformity in chironomidae larvae with various degrees of worn,such as median teeth with moderately worn,substantial worn,median and lateral teeth folked. the percentage of deformities was higher in the ditch canalization received wastewater from dormitory and household than other sites. data of water quality and chironomids larvae were analyzed with principal component analysis (pca). strong correlations were found between chironomidae larvae and the water quality parameters of orthophosphate (po4 3-),ammonia-nitrogen (nh3-n),nitrate-nitrogen (no3-n),dissolved oxygen (do),ph and water temperature. © 2017 jordan journal of biological sciences.