Eretmoptera from Washington State, USA: maritime or terrestrial midge?

Abstract

Washington State, USA has extensive coastal habitats that extend from marine or estuarine ecosystems upstream to the upper mixing zone where tidal surge and freshwater meet. We document a rare maritime chironomid genus, Eretmoptera Kellogg, 1900, from these habitats. The larvae of Eretmoptera were identified from 21 samples composed of 17 sites in the Puget Lowlands and Coast Range ecoregions based on a total of 1067 samples examined. Larvae were compared to reference material to confirm identification. We document Eretmoptera from low order forested streams in urban and private lands. Many sites sampled were near marine habitat and likely experienced saltwater intrusion while at least six sites were far from saltwater intrusion and were likely fully freshwater. We compare larval habitat for Eretmoptera in this study to larval habitat of the sub-Antarctic and Antarctic E. murphyi Schaeffer, 1914, the only species in the genus for which larvae have been associated. The georeferenced data provided in this study should spur further research to find and associate all life stages for Eretmoptera in Washington State to verify the genus identification and to help solve its taxonomic position within maritime and terrestrial Orthocladiinae.