Stoneflies - Plecoptera: Nemouridae of Gunnison County, ColoradoZapada oregonensis - Oregon Forestfly, Early Winter Brown(Claassen, 1923)Updated 12 January 2026
DescriptionVery similar to Zapada haysi, but usually doesn't appear sympatrically or at the same time and place (Kondratieff and Baumann 2002). The nymphs are impossible to tell apart from Z. haysi.HabitatLess common than Z. haysi in Colorado. Found in spring-fed creeks and small rivers of the mountains.Life HistoryNymphs studied by Short and Ward (1981) ate detritus while living in a 3rd order stream.Locations CollectedWhite Pine Creek, East Fork Cimmaron Creek.NotesThe genus Zapada was previously named Nemoura. Older publications may refer to this species as Nemoura oregonensis.Good LinksOn this website:Other Websites: Photos, Map, Taxon Identifier Numbers - from the Global Biodiversity Information Facility Zapada oregonensis at GBIF Photo - Adult from Michael Wigle Photography. Photos, Map, Museum specimens, DNA - Barcodinglife.org ReferencesBaumann,RW; Gaufin, AR and Surdick,RF 1977 The stoneflies (Plecoptera) of the Rocky Mountains. Memoirs of the American Entomological Society 31, 1-208. PDFQuote from page 48: "This species is common in creeks and small rivers in the Northern Rocky Mountains. The adults emerge from March through August. This species has been recorded from Utah previously, but all specimens seen proved to be Zapada haysi (Ricker)." They mention Zapada oregonensis is present in Gunnison County. Claassen,PW 1923 New species of North American Plecoptera. Canadian Entomologist 55, 257-263,281-292. Frison,TH 1937 II. Descriptions of Plecoptera with special reference to the Illinois species. Illinois Natural History Survey Bulletin 21 (3) 78-99. Discussed as Nemoura oregonensis. Illustrations of female front wing and terminal abdominal segments (Figure 70 on page 84). Knight,AW and Gaufin,AR 1966 Altitudinal distribution of stoneflies (Plecoptera) in a Rocky Mountain drainage system. Journal of the Kansas Entomological Society 39 (4) 668-675. They refer to this species as Nemoura oregonensis 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 392: "This species is quite similar to Z. haysi, but does not occur sympatrically. However, both species occur at Fish Creek in Routt County" Muchow,CL and Richardson,JS 1999 Unexplored diversity: macroinvertebrates in coastal British Colombia headwater streams. In Proceedings of a Conference on the Biology and Management of Species and Habitats at Risk, Kamloops, BC (2) 503-506. PDF The authors studied the emergence of adult stoneflies from intermittant and continuously flowing streams in British Columbia. They found that Zapada oregonensis emerged from both permanent and intermittant streams, even when the intermittant streams had no surface flow. Needham,JG and Claassen,PW 1925 A Monograph of the Plecoptera of North America. Entomological Society of America, Lafayette, Indiana. 397 pages. PDF Discussed as Nemoura oregonensis. 
Radford,DS and Hartland-Rowe,R 1971 The life cycles of some stream insects (Ephemeroptera, Plecoptera) in Alberta. The Canadian Entomologist, 103(4) 609-617. Names have changed since 1971:
Short,RA and 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." Ward,JV, Kondratieff,BC and Zuellig,RE 2002 An Illustrated Guide to the Mountain Stream Insects of Colorado. 2nd ed. University Press of Colorado, Boulder, Colorado. 219 pages. Illustration of Z. oregonensis nymph on page 68, figure 28. 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. U.S. Geological Survey Data Series 606, 257 p. PDF - caution 46MB Quote from page 51: "Zapada oregonensis is a more Northern Rocky Mountain species that is considered uncommon in Colorado (Baumann and others, 1977). Larvae occur in small- to medium-sized streams." The elevation range is 5,250-11,200 feet and the adults emerge from May-September. |