Macropelopia Thienemann, 1916

Namayandeh, Armin, Hudson, Patrick L., Bogan, Daniel L. & Hudson, John P., 2024, Chironomidae (Diptera: Insecta) of Alaska, USA, with descriptions of new species and a checklist, Zootaxa 5511 (1), pp. 1-95 : 44

Macropelopia Thienemann, 1916

In the past, species in this genus have been relegated to various subgenera, which are now raised to full generic status. Roback (1977) noted that only two species of Macropelopia from North America are known: Macropelopia decedens (Walker, 1848) and Macropelopia (Macropelopia) sp. A. We may have found a larva of M. decedens collected from Spike Creek, Revillagigedo Island ( Fig. 9F ), and found the pupae of M. sp. A, and an undescribed pupa from a first-order stream on Lena Point north of Juneau. Roback (1977) indicated that M. sp. A falls within the notata group based on tergite I scar of the pupa, which is similar to that of the European species Macropelopia notata (Meigen, 1818) . We observed the hypopygium of a pharate adult male dissected from mature pupa, showing the presence of small inferior volsella. The thoracic horns of the two species are also similar. Therefore, there is a good reason to believe these are the same species. Other characters are not visible due to the condition of the specimen. At this time, without the associated adult, this cannot be confirmed with certainty. Our larval collections come from several streams in the southwest corner of Central Alaska, including a tributary to the Koksetna River, Steambath Creek, Upper Talarik Creek, and a tributary to the Stuyahok River. We have also collected larvae from many streams in Southeast Alaska, including a tributary to the Pavlof River on Chichagof Island, a tributary to the Salmon River near Gustavus, a tributary to Whitman Creek on Revillagigedo Island, and a tributary to Yatuk Creek, north of Naukati on Prince of Wales Island.

Cranston & Epler (2013) note that this genus might be overlooked in routine biomonitoring because of its similarity to other Macropelopiini . The authors also noted that larvae of species in this genus live in fine sediments associated with cool water bodies such as springs, brooks, lakes, and bogs.

Figures

FIGURE 9. Some of the study’s collection sites and habitats of Chironomidae in Alaska. A. Turner Lake, near Juneau. B. Bartlett River in Glacier Bay National Park and Preserve. C. Alaska, USA and Yukon Territory, Canada international boundary. D. Auke Lake outlet in Juneau. E. Rachael Lake near Bettles. F. Spike Creek on Revillagigedo Island. G. Auke Lake in Juneau. H. Hebert River near Juneau. I. Nugget Falls, in Juneau. J. Forested bog near Eagle crest Ski Area, Douglas Isand. K. Creek outlet at Margaret Bay on Revillagigedo Island. L. Mount Roberts (foreground) in Juneau. M. A snow-melt stream (arrows) on Thunder Mountain, Juneau. N. Tangle River near Paxon. O. Kanuti Lake outlet in Kanuti National Wildlife Refuge. P. Fish Creek on Douglas Island. Q. Antler River near Juneau. R. Harbor Mountain, Sitka. S. Observing Thalassosmittia marina (Saunders, 1928) larvae in intertidal rock pools near Lena Point, Juneau. T. Larvae of T. marina (arrows) inhabiting a rock pool in the upper tidal zone and feeding on periphytic algae near Lena Point, Juneau. U.A tundra lake east of King Salmon. V. Swarm of Corynocera oliveri group adults on a tundra lake east of King Salmon.