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Stoneflies - Plecoptera: Nemouridae of Gunnison County, Colorado

Zapada haysi - Intermountain Forestfly

(Ricker 1952)

Updated 9 Oct 2019

The animal on the right was stained with Rose Bengal dye to assist in finding it in the rest of the detritus from the riverbottom. Notice the 4 simple cervical gills.


Found in streams and rivers throughout Gunnison county, common in Colorado. In a good year, adults are easily collected as they run across the snow with other winter stoneflies in the winter and spring.

Life History

Adults are present on the snow from April to May and in the riparian zone into mid summer. Population size varies considerably year to year in the upper East River drainage.

Local Research Results

Allan studied drift and trout diets in August of 1975 in Cement Creek. He found Zapada haysi was 2.1% of total drift. Brook and Brown Trout diets correlated with species available in the drift.

When Zapada haysi exceeded the common mayfly Baetis bicaudatis in size, trout in Cement Creek ate more Z. haysi than B. bicaudatis (Allan, 1978).

Locations Collected

Cement Creek, Copper Creek, East River. Often found with Zapada cinctipes.


The Chionea Zapada was previously named Nemoura. Older publications may refer to this species as Nemoura haysi. This is the type species for the genera Zapada. Larvae are indistinguishable from Zapada oregonensis.

Good Links

On this website:
Zapada Introduction
Zapada oregonensis

Other Websites:
Trichomycetes Slides Contributed by R. W. Lichtwardt http://www.bsu.edu/classes/ruch/msa/litchwart.html
     Has a link to a picture of Genistelloides helicoides from the gut of a Z. haysi collected near the Rocky Mountain Biological Laboratory in Gunnison County.


Allan,JD 1978 Diet of brook trout (Salvelinus fontinalis Mitchell) and Brown Trout (Salmo trutta L.) in an alpine stream. Internationale Vereinigung für Theoretische und Angewandte Limnologie Verhandlungen 20, 2045-2050.

Baumann, RW Gaufin, AR, Surdick, RF 1977: The stoneflies (Plecoptera) of the Rocky Mountains. Memoirs of the American Entomological Society 31, 1-208.
     Quote from page 48: "This species is widely distributed but is not usually common. The nymphs are found in both creeks and small rivers. The adults emerge from April to July." They show this species is present in Gunnison County, Colorado.

Cather,MR and Arden R. Gaufin,AR 1976 Comparative ecology of three Zapada species of Mill Creek, Wasatch Mountains, Utah (Plecoptera: Nemouridae). American Midland Naturalist 95(2) 464-471.
     Abstract: " Three species of Zapada (Plecoptera) were studied in Mill Creek, Wasatch Mountains, Utah, and their life histories, growth rates, distribution and emergence compared. All species, Z. haysi (Ricker), Z. cinctipes (Banks) and Z. columbiana (Claassen) have a univoltine life history and a slow seasonal life cycle.
Temporal and spatial distributions and staggered emergence periods serve to ecologically separate these species. All three grow most rapidly in autumn and early winter, with a seasonal succession in the maximum absolute growth rates. Maximum size overlap between Zapada haysi and Z. cinctipes occurs in spring prior to and during emergence when growth is complete, whereas minimum overlap occurs in autumn when growth is fastest. Zapada haysi and Z. columbiana were found more at the upper cooler stations and Z. cinctipes at the lower stations. Zapada cinctipes was collected from late February to late June (one ♀ in mid-January), Z. columbiana mostly in March and Z. haysi from early April to mid-June.
The mean size of the adults of Zapada cinctipes decreased as emergence progressed and may be related to increasing stream temperatures and photoperiod."

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.
     Abstract: "The stonefly component of a naturally reproducing population of brook trout (Salvelinus fontinalis) was studied by analyzing 216 stomach pump samples collected between May 15 and August 10, 1991 and 1992, from Libby Creek, an alpine stream in the Medicine Bow National Forest in Wyoming. Stoneflies constituted 10.3% of the total items recovered and were the second most abundant order in the samples. Nineteen species of Plecoptera representing five families were identified. Approximately 43% of all stoneflies were Sweltsa lamba; the next most prevalent species was Zapada haysi (12%). The other prevalent insect orders in the samples were Diptera (57.2%), Ephemeroptera (8.4%) and Trichoptera (6.1%). Terrestrial Coleoptera, Hymenoptera, and Hemiptera were most common in July and August."

Finn,DS and Poff,NL 2008 Emergence and flight activity of alpine stream insects in two years with contrasting winter snowpack. Artic, Antarctic, and Alpine Research 40(4)638-646. PDF
     A few full paragraph quotes: "Across all orders, there were six species that we considered common (range 17-373 individuals/year): Ameletus celer McDunnough and Cinygmula spp. (Ephemeroptera), Zapada haysi Ricker and Alloperla pilosa Needham and Claassen (Plecoptera), Asynarchus nigriculus Banks (Trichoptera), and Stegopterna acra Currie, Adler, and Wood (Simuliidae)." "For five of the six common species, we observed the progress of emergence over the full season at an approximately one-month delay in 2003 compared to 2002 (Fig. 2). The lone exception was the stonefly Zapada haysi, which is one of the earliest emergers from this stream and exits the water as soon as snowcover recedes. Because traps were set immediately following snowmelt in 2003 but not in 2002, data are considerably lacking for Z. haysi in early 2002; therefore, Figure 2f should be interpreted with caution. A paired t-test using the four most common later-emerging species revealed that timing of earliest emergence was significantly different between years (one-tailed test: p = 0.003)."

Richardson,JS 2001 Life cycle phenology of common detritivores from a temperate rainforest stream. Hydrobiologia 455 (1) 87-95. Abstract

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 is a common species in the northern part of the state, often sympatric with Z. cinctipes. Nymphs generally key in
Baumann et al. (1977) as Z. oregonensis group. "

Peckarsky,BL 1980 Influence of detritus on colonization of stream invertebrates. Canadian Journal of Fisheries and Aquatic Sciences 37, 957-963.

Peckarsky,BL 1983: Biotic interactions or abiotic limitations? A model of lotic community structure. In: Dynamics of Lotic Ecosystems. Eds: Fontaine III,Thomas D; Bartell,Steven M Ann Arbor Science, Ann Arbor, Michigan, 303-323.

Peckarsky,BL 1990 Habitat selection by stream-dwelling predatory stoneflies. Canadian Journal of Fisheries and Aquatic Sciences 48, 1069-1076.

Peckarsky,BL 1991a A field test of resource depression by predatory stonefly larvae. Oikos 61 1, 3-10.

Richardson, JS 2001 Life cycle phenology of common detritivores from a temperate rainforest stream. Hydrobiologia 455 (1) 87-95. DOI - 10.1023/A:1011943532162
     Abstract: The timing of life cycles, including growth rates, was determined for eight common species of detritivorous insects in a second-order stream in southwestern British Columbia, Canada. Six of the species (Zapada cinctipes, Z. haysi, Malenka californica, M. cornuta, Capnia sp., and Lepidostoma roafi) had simple, univoltine life cycles. The leuctrid stonefly Despaxia augusta has a 2-year life cycle, with an apparent egg diapause of about 6 months. The chironomid Brillia retifinis produced at least three generations per year. The major growth periods for the set of species considered here span the entire year. Adults of several species exhibited seasonal declines in size at emergence, but one species had larger adults as the emergence period proceeded. Closely related taxa had more similar life cycle timing than more distantly related species suggesting a degree of phylogenetic constraint in phenology of their life cycles. The influence of the timing of leaf drop on timing of life cycles for these animals does not fit with proposed scenarios based on fast and slow leaf processing rates.

Ricker, W.E. 1952. Systematic studies in Plecoptera. Indiana University Publications, Science Series 18, 200 pages, Bloomington, Indiana.

Ricker,WE 1992 Origin of stonefly names proposed by Ricker and collaborators. Perla, 18(1) 12 pages. PDF
      Quote from page 11: "Zapada Ricker 1952 (as sg. of Nemoura). Russian zapad = west. Occurs mainly in western North America.
haysi (Ricker 1952) - Nemoura (Zapada). Mr. R. A. Hays collected extensively and identified stoneflies in the vicinity of Bozeman, Montana. "

Short,RA; Canton,SP and Ward,JV 1980 Detrital processing and associated macroinvertebrates in a Colorado mountain stream. Ecology, 61(4), 727-732. PDF
     Z. haysi nymphs were found in all 4 of the plant species used to make leaf packs; alder, willow, aspen and pine.

Shepard, WD. and Stewart KW 1983 Comparative Study of Nymphal Gills in North American Stonefly Genera and a New, Proposed Paradigm of Plecoptera Gill Evolution. Miscellaneous Publications of the Entomological Society of America 13:1-57
     Illustration of nymphal osmobranchiae (gills) on page 34.

Short,RA and Ward,JV 1980 Macroinvertebrates of a Colorado high mountain stream. The Southwestern Naturalist, 23-32. PDF

Stewart,KW; Hassage,RL; Holder,SJ and Oswood,MW 1990 Life cycles of six stonefly species (Plecoptera) in subarctic and arctic Alaska streams. Annals of the Entomological Society of America 83(2)207-214.
     Abstract: Nymphal growth and emergence of adults are described for six species of stoneflies (Plecoptera) found in subarctic and arctic Alaska. The two Nemouridae studied are semivoltine; adults of Zapada haysi (Ricker) are present from May to July and adults of Nemoura arctica Esben-Petersen occur from June to July. The remaining four species are univoltine. Plumiperla diversa (Frison) (Chloroperlidae) has most of its growth occurring during the summer with emergence the following May-September. Taenionema pacificum (Banks) (Taeniopterygidae) completes nymphal growth by the end of January and has an early emergence (April-June). Adults of Arcynopteryx compacta (McLachlan) (Perlodidae) are present from May to August, and growth of nymphs is rapid during summer and fall. Isoperla petersoni Needham ∓ Christenson (Perlodidae) adults are present from June to mid-August, and nymphal growth is interrupted by winter and resumes in the spring; the three other univoltine species studied tend to complete growth before the onset of winter. Growth of these six species is tied to seasonal temperature variation.

Stewart,KW and Stark,BP 2002: Nymphs of North American Stonefly Genera. 2nd edition The Caddis Press, Columbus, Ohio. 510 pages. Illustrations of nymph on pages 222-223, figures 9.25-9.26

Brown, Wendy S. 2004 Plecoptera or Stoneflies of Gunnison County, Colorado