Stoneflies - Plecoptera: Capniidae of Gunnison County, Colorado
Capnia confusa Claassen 1936
Widespread Snowfly, Winter Stonefly
Updated 22 January 2019
On this website:
Photos, Map, Museum specimens, DNA - Barcodinglife.org
Baumann,RW, Gaufin,AR and Surdick,RF 1977 The stoneflies (Plecoptera) of the Rocky Mountains. Memoirs of the American Entomological Society 31, 1-208.
Quoted from page 68: "This species occurs commonly in creeks,with the adults emerging from Febuary to June."
Claassen,PW 1936 New names for stoneflies (Plecoptera). Annals of the Entomological Society of America 29: 622-623.
Duffield,RM and Nelson,CH 1998 Stoneflies (Plecoptera) in the diet of brook trout (Salvelinus fontinalis Mitchell) in Libby Creek, Wyoming, USA. Hydrobiologia 380, 59-65.
Although collected as adults in the streamside vegetation, Capnia confusa adults were not found in the stomach contents of the trout living in the stream. However, some larvae were found in trout gut contents.
Kondratieff,BC and Baumann,RW 2002 A review of the stoneflies of Colorado with description of a new species of Capnia (Plecoptera: Capniidae). Transactions of American Entomological Society 128 3, 385-401.
Quote from page 388: " This later emerging winter stonefly (March to July) is one of the widespread and common stonefly species in Colorado. Capnia confusa adults can be found abundantly emerging from medium to large sized streams ranging in elevation from 1,520 m to 3,860 m. Adults are sometimes still active as late as July at higher elevation streams."
Nelson,RC and Baumann,RW 1989 Systematics and distribution of the winter stonefly genus Capnia (Plecoptera: Capniidae) in North America. Great Basin Naturalist 49, 289-363. PDF
They placed C. confusa in the Vernalis Group. They comment "this is probably the most widespread member of the genus in North America"
Newell,RL; Baumann,RW and Stanford,JA 2008 Stoneflies of Glacier National Park and Flathead River basin, Montana. International Advances in the ecology, zoogeography, and systematics of mayflies and stoneflies. University of California Publications in Entomology, Berkeley and Los Angeles, pp.173-186. PDF
Quote from page 176: "Stoneflies recorded from hyporheic habitats (pumped wells) included: Alloperla severa, Capnia confusa, Claassenia sabulosa, Diura knowltoni, Hesperoperla pacifica, Isocapnia crinita, I. grandis, I. integra, I. vedderensis, Isoperla fulva, Kathroperla, Paraperla frontalis, and P. wilsoni"
Radford,DS and Hartland-Rowe,R 1971 Emergence patterns of some Plecoptera in two mountain streams in Alberta. Canadian Journal of Zoology, 49(5), 657-662.
Ruse,LP and Herrmann,SJ 2000 Plecoptera and Trichoptera species distribution related to environmental characteristics of the metal-polluted Arkansas River, Colorado. Western North American Naturalist 60 (1) 57-65. PDF
They looked at the Arkansas River above and below some notorious heavy metal mine pollution sources, California Gulch and the Leadville Drain. They found that adult C. confusa were eliminated by the Leadville Drain, recovered and reappeared a ways downstream, then were gone below California Gulch. After freshwater was added to the Arkansas River from the western slope, they reappeared at one site. They were probably missing farther downstream due to warmer water temperatures and would have been missing from a clean river as well.
Short,RA; Canton,SP and Ward,JV 1980 Detrital processing and associated macroinvertebrates in a Colorado mountain stream. Ecology, 61(4), 727-732. PDF
Capnia confusa nymphs were found in all 4 of the plant species used to make leaf packs; alder, willow, aspen and pine.
Short,RA; Ward,JV 1981 Trophic ecology of three winter stoneflies (Plecoptera). American Midland Naturalist 105, 341-347.
Abstract: " Winter stoneflies (Zapada oregonensis, Z. cinctipes and Capnia confusa) used detritus as a nymphal food almost exclusively and dominated the shredder biomass in a third-order mountain stream in Colorado. Laboratory feeding trials showed that ingestion rates and fecal production were temperature-dependent, although not greatly different between aspen or alder leaf discs. Assimilation efficiency (AE) was not temperature-dependent. Higher AE values for alder indicate that it is superior to aspen as a food source. High consumption rates (ca. 30% of body weight/day) by the shredders, even at low temperatures, would result in the conversion of considerable quantities of leaf litter to finer particles. However, size fraction analysis of egested material indicated that particle size reduction by shredder processing only partially explains detrital composition in a stream dominated by fine-particle feeding detritivores."
Zuellig,RE; Heinold,BD; Kondratieff,BC and Ruiter,DE 2012 Diversity and distribution of mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera) of the South Platte River Basin, Colorado, Nebraska, and Wyoming, 1873-2010 (No. 606). US Geological Survey. PDF - caution 46MB
Elevation collected 4,950-10,500ft Adults were found February-July. Remarks from page 38: "This is one of the most common and widespread species of the genus Capnia (Kondratieff and Baumann, 2002). It also has one of the latest emerging periods of winter stoneflies with females present from February into July (Nelson and Baumann, 1989). Records for this species were available from small high and low elevation streams ranging from 10,500 to 4,950 ft in elevation."
Brown, WS 2004 Plecoptera or Stoneflies of Gunnison County, Colorado
We're fools whether we dance or not, so we might as well dance. ~ Japanese Proverb