Morphology, Cytogenetics and DNA barcodeof the Chironomidae (Diptera) in Thailand

บทคัดย่อ

The larvae of the family Chironomidae are important components of freshwater ecosystems. However, taxonomic knowledge of these insects is poorly developed in Thailand. In this study we examined multiple character sets for species identifi cation of the larval stage of three Chironomid species, Chironomus striatipennis, C. javanus and Kiefferulus tainanus. Specimens were collected from Maha Sarakham and Roi Et Province, Thailand.The morphological characters of these species agreed with previously published descriptions from other geographic regions. Cytological examinations revealed that C. striatipennis has four polytene chromosomes with the arm combinations of AE, CD, BF and G. The nucleolar organizer and Balbiani Ring were located on the chromosome arm G. C. javanus has four polytene chromosomes, but arm combinations could not be determined due to the poor quality of the chromosomes except for arm G. K. tinanus has four chromosomes,and chromosome arm G was connected to chromosome E. DNA barcoding based on mitochondrial cytochrome c oxidase subunit I (COI) sequences perfectly differentiated these species. The results are consistent with phylogenetic analysis that revealed that all three species formed monophyletic clades with strong support. However, two distinct groups were found among the specimens of C. striatipennis indicated cryptic diversity in this species that needs further examination.