Molecular Identification of Chironomid Species

Despite their utility as indicators of aquatic ecosystem health, chironomid species are generally difficult to identify using the morphological features of their larvae. Molecular identification should significantly improve the reliability of species identification of known chironomid larvae that have important indicator roles. It may also aid in the discovery and phylogenetic placement of new chironomid species with different indicator potentials. Preliminary analyses of the internal transcribed spacer regions (ITS) of chironomid rDNA provide sequence data that suggests high amounts of variation between species of this group and at the same time the intraspecific variation is low. The polymerase chain reaction (PCR) amplification and restriction enzyme digests of these ITS regions produce characteristic fragments for each species tested to date. Nucleotide sequence analysis of these regions confirmed the interspecific diversity found in both the ITS-1 and ITS-2 region.