Identifying Stream Insect Larvae With DNA Barcodes in Alaska's National Parks

Biological monitoring of water quality — including the National Park Service's Central Alaska Network Stream Monitoring Program — depends on collecting aquatic insects from streams and rivers and identifying them. Most of them live in the water only as larvae, and although many common larvae can be named to genus or species by their shape, not all can.

Webber Creek in Yukon-Charley Rivers National Preserve, one of the habitats where dance fly larvae live. NPS.

DNA barcoding can identify them more finely.

A dance fly larva gets a name

A common larval dance fly in Alaska's streams had never been described and was known only as "Genus B." Comparing the larvae's barcodes with those in the Barcode of Life Database showed they were genetically identical to adults of a known, though still unnamed, species of the genus Proclinopyga. That made it possible to write a key for identifying the genus's larvae.

The resulting paper describes the larva of Proclinopyga for the first time, linked to the adults by COI mitochondrial DNA barcodes. The larvae live in the coarse gravel of riffles and other fast-flowing stretches of streams and small rivers; they turn up only occasionally in samples from the stream bed, sometimes alongside larvae of other dance fly genera. The paper describes and illustrates the final larval stage and updates the key to the larvae of the North American genera of Clinocerinae.

New species records for Alaska

Applied to insects from bioassessment samples collected in Alaska's national parks and preserves, barcoding revealed 28 insect species never before reported from Alaska. Of these, 21 are also new records for the United States, and 7 are new for North America (Greenland excepted).

Sources

• National Park Service, Central Alaska Inventory and Monitoring Network, "Insect Larvae Identification with Genetic Barcoding." https://www.nps.gov/articles/000/dance-fly-larvae.htm
• B. J. Sinclair, T. Simmons, M. B. Cole, J. M. Webb and S. Sullivan, "Confirmation and description of the larva of the aquatic dance fly, Proclinopyga Melander (Diptera: Empididae: Clinocerinae)," Proceedings of the Entomological Society of Washington 123(4): 852–861, 2022.
• J. M. Webb, M. B. Cole and T. Simmons, "DNA Barcoding Takes Bioassessment Further: New Distribution Records for Aquatic Macroinvertebrates from Alaskan National Parks," Proceedings of the Entomological Society of Washington 124(1): 131–149, 2022. https://doi.org/10.4289/0013-8797.124.1.131
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