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Stoneflies - Plecoptera: Perlodidae of Gunnison County, Colorado

Isoperla fulva - Western Stripetail

Claassen 1937
Updated 12 Jan 21
TSN 103004


Under stones in fast water of streams.

Life History

Richardson and Gaufin (1971) found their diet was approximately 70 percent animal matter and 30 percent plants. Ephemeroptera and Chironomidae nymphs were the most common. Terrestrial arthropods, Plecoptera nymphs, Trichoptera and Simuliidae larvae were also found. Specimens from Taylor River and West Elk Creek fed heavily on Simuliidae larve and to a lesser degree on Trichoptera Larvae.

Fuller and Stewart 1977 found that small nymphs in the Gunnison River at Lost Canyon Resort were phytophagous eating filamentous algae (48%, mostly Ulothrix), diatoms (16% mostly Fragilaria, Synedra and Cymbella) and detritus (28%). Animal matter was only 9% of their diet. Nymphs shifted to a 72% animal diet by December, eating Chironomidae and Ephemeroptera, while filamentous algae disappeared from their gut contents. Late instar nymphs ate primarily Chironomidae and a few Trichoptera larvae in May and by June ate Chironomid larve almost exclusively with a high electivity. There was no selection for larger Chironomids. Sandberg and Stewart (2003) published sonograms of the monophasic call of an I. fulva male collected in Quartz Creek near Pitkin compared to ones collected in Umatilla County, Oregon. They discussed previous recordings of I. fulva with this data finding similarities in beat counts, intervals and total call duration, but noting enough differences to suggest the presence of stonefly drumming dialects over the North American range of this species.

Locations Collected

Taylor River, West Elk Creek, East Elk Creek, East River, Gunnison River at the Lost Canyon Resort. The Illinois Natural History Survey has a specimen in their data base from Agate Creek near Sargents on the 7th of June 1954.

Good Links

On this website:
Introduction to Isoperla
Key to Perlodidae Nymphs

Other Websites:
Photos, Map, Museum specimens, DNA - Barcodinglife.org

Photos - from Troutnut.com


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 144: "This species is common in creeks and rivers throughout its range. The adults emerge from April to August."

Claassen,PW 1937 New species of stoneflies (Plecoptera). Canadian Entomologist 69, 79-82. Type specimen
     First description of this species.

Fuller,RL and Stewart,KW 1977 The food habits of stoneflies (Plecoptera) in the Upper Gunnison River, Colorado. Environmental Entomology (6) 293-302.
     Abstract: "Gut contents of 1,463 stonefly nymphs, comprising 10 species, from the Gunnison River, Colorado, were analyzed from Dec., 1974-Oct., 1975, in relation to food availability. Pteronarcella badia fed primarily on detritus and moss. Perlidae and Perlodidae mature nymphs were all carnivorous, but showed considerable seasonal-developmental shifting in diets and preference during earlier stages. Early instar Isoperla fulva nymphs were herbivore-detritivores, then gradually shifted through an omnivorous to carnivorous diet as development proceeded. Claassenia sabulosa and Hesperoperla pacifica remained carnivorous throughout development. Dominant prey groups were chironomids, mayflies and caddisflies. Horn's Coefficient of Dietary Overlap showed significance among all predator species for major food categories, but subtle mechanisms such as prey species-and size-selectivity and temporal succession provided sufficient partitioning of the abundant food resources to allow for coexistence. Large Claassenia sabulosa nymphs in August selected more mayflies after dark than in the afternoon. No behavioral selection by predacious stoneflies was indicated for the chironomids Ablabesmyia sp., Cricotopus sp., Prodiamesa sp., and Rheotanytarsus sp."

Fuller,RL and Stewart,KW 1979 Stonefly (Plecoptera) Food habits and prey preference in the Dolores River, Colorado. American Midland Naturalist, 101(1) 170-181. First page

Hassage,RL 1989 Life histories, behavior and space partitioning in selected species of western North American Plecoptera. pHd Dissertation, University of North Texas. 105pgs. PDF
     Abstract: "Five species of stoneflies (Zapada haysi, Plumiperla diversa, Taenionema pacificum, Isoperla petersoni, Arcynopteryx compacta) from the North Slope and Interior of Alaska were examined for seasonal patterns of emergence of adults and growth of nymphs. Generally growth was retarded during the winter in this region, and all species except I. petersoni completed growth prior to January. The life cycles of six stonefly species (Prostoia besametsa, Triznaka signata, Sweltsa coloradensis, Isoperla fulva, Skwala parallela, Claassenia sabulosa) are described from northern New Mexico. In this region growth was generally less retarded during the winter than in Alaska; P. besametsa completed all nymphal growth during late fall and winter. Drumming behavior of a Colorado population of Pteronarcella badia was described using an evolutionary framework to explain the maintenance of signal variation in this species. Laboratory experiments were used to explore the effect of intraspecific and interspecific interactions on spatial partitioning in P. badia and Claassenia sabulosa. P. badia exhibited clumping and distributed itself as the surface area of substrate in low densities; however, in the presence of C. sabulosa its distribution was random and different from available surface area. A field study was used to examine spatial partitioning by three New Mexico stonefly species (I. fulva, P. besametsa, T. signata) and to ascertain patterns of microdistribution relating to several abiotic and biotic factors. Generally, there was an interaction of the measured abiotic parameters (current, water temperature, time) with nymphal size. Additionally, void space and sample volume were successfully used to compare biotic densities among leaf and mineral substrates, which were higher in leaf packs than in mineral substrates."

Hassage,RL and Stewart,KW 1990 Growth and voltinism of five stonefly species in a New Mexico mountain stream. The Southwestern Naturalist, 35 (2)130-134. Abstract and first page

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 395: "This species can be abundant in medium to large-sized streams of the Mountain and Plateau regions, especially in the southern half of the state."

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"

Richardson,JW; Gaufin,AR 1971 Food habits of some western stonefly nymphs. Transactions of American Entomological Society 97, 91-121.

Sandberg,JB and Kondratieff,BC 2013 The Isoperla of California (Plecoptera: Perlodidae); Updated male descriptions and adult keys for 18 western Nearctic species. Illiesia (9)34-64. PDF

Sandberg,JB and Stewart,KW 2003 Continued studies of drumming in North American Plecoptera; Evolutionary implications. In: Research Update on Ephemeroptera and Plecoptera. Ed: Gaino,E University of Perugia, Perugia, Italy, 73-81.
Has the sonogram of an I. fulva monophasic call from Gunnison County.

Szczytko,SW; Stewart,KW 1979a The genus Isoperla (Plecoptera) of western North America; holomorphology and systematics, and a new stonefly genus Cascadoperla. Memoirs of the American Entomological Society 32, 1-120.

Szczytko,SW and Stewart,KW 1979c Drumming behavior of four Western Nearctic Isoperla (Plecoptera) species. Annals of the Entomological Society of America 72(6)781-786.

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 I. fulva nymph on page 73, figure 33.

Brown,WS 2004 Plecoptera or Stoneflies of Gunnison County, Colorado