PARENT SESSION
Tuesday, August 8, 5:00-6:30 pm
Poster Session 10 - Genetics, evolution, and paleoecology
Exhibit Hall, Ballroom Level, Cook Convention Center

Genetic identification profiles of Cricotopus sp. (Diptera: Chironomidae) based on mitochondrial gene cytochrome oxidase subunit I sequence variation.

Sinclair, Colleen^*,1, Gresens, Susan¹, ¹ Department of Biological Sciences, Towson, MD

ABSTRACT- Chironomids frequently comprise the most abundant group of macroinvertebrates collected in water quality surveys. Most species in the genus Cricotopus are considered tolerant to organic enrichment and/or toxic metals. High abundance of Cricotopus species and species of Orthocladius are both commonly associated with streams degraded by urban runoff. The ability to reliably distinguish Cricotopus and Orthocladius should provide useful information for bioassessment and stressor identification. However these genera are very difficult to distinguish using the morphology of the larval stage, which is typically collected. Molecular approaches are now being used for identification and taxonomic resolution in many animal taxa. A goal of this study was to develop a method in which unique sequence variation in the mitochondrial gene cytochrome oxidase subunit I could be associated with Cricotopus species identified by pupal morphology. A second goal was to compare the degree of sequence variation in a population of Cricotopus bicinctus collected from a highly metal-polluted stream with several other populations of C. bicinctus from streams receiving moderate to low levels of urban runoff. Larval chironomids were collected from nine streams in the Baltimore, MD area, and reared to obtain pupal exuviae and associated adults. We developed genetic profiles for eight described species of Cricotopus, and an additional five potentially cryptic species. C. bicinctus populations showed little variation in genetic profile. This method can be used to develop an accurate and rapid method for identification of Cricotopus spp., and can make a useful contribution to development of keys to nearctic Cricotopus.

Key words: genetic profile, chironomidae, bioassessment