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Plecoptera: Perlodidae of Gunnison County, Colorado

Introduction to Isoperla
Stripetails, Yellow Sallies, Green-winged stoneflies

Banks 1906
Updated 22 June 21
TSN 102995
Isoperla nymph from a small spring fed stream on the flank of Gothic Mountain, Elk Mountains, Colorado

Provisional Species List

Isoperla fulva
Isoperla longiseta
Isoperla mormona
Isoperla pinta
Isoperla quinquepunctata
Isoperla sobria


Here is a key for Isoperla adults in Western US and California.

Good Links

On this website:
Perlodidae Introduction
Isoperla phalerata

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

Illustration - from the University of Alberta Entomology Collection
     Has illustration of male genitalia, description, habitat information, range and more.

Photos - from Troutnut.com

Pesticides database - from the Pesticide Action Network (PAN)


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 135: "The two subfamilies of Perlodidae are often difficult to separate, except on the basis of male genitalia. Isoperlinae exhibits a loss of the epiproct and the lobe on the seventh sternum, a retention of the lobe on the eighth sternum, and a modification of the subanal lobes into hooks (figs. 417, 419). Gills and gill remnants are always lacking in the Isoperlinae, but are retained as simple filaments in some representatives of the Perlodinae. A transverse ridge and posterior junction of the Y-ridges to the furcal pits charaterize the typical mesosternal ridge pattern of adults and immatures (figs. 24, 25). Adults of the subfamily are yellow or brown colored and generally smaller than their Perlodinae counterparts. Nymphs are often brightly striped in brown and yellow. Nymphal abdominal color patterns, adult genitalia and setal patterns are used to differentiate species. Isoperla is the only genus of Isoperlinae recorded from the Rocky Mountains."

DeWalt,RE and Stewart,KW 1995 Life histories of stoneflies (Plecoptera) in the Rio Conejos of southern Colorado. Great Basin Naturalist 55, 1-18. PDF

DeWalt,RE; Stewart,KW; Moulton,SR; Kennedy,JH 1994 Summer emergence of mayflies, stoneflies, and caddisflies from a Colorado mountain stream. Southwestern Naturalist 39 (3) 249-256. PDF

Dodds,GS and Hisaw,FL 1925 Ecological studies on aquatic insects. IV. Altitudinal range and zonation of mayflies, stoneflies and caddisflies in the Colorado Rockies. Ecology 6(4)380-390. Abstract PDF

Fuller,RL and Stewart,KW 1977 The food habits of stoneflies (Plecoptera) in the Upper Gunnison River, Colorado. Environmental Entomology 6, 293-302.

Gill,BA; Sandberg,JB and Kondratieff,BC 2015 Evaluation of the morphological species concepts of 16 western Nearctic Isoperla species (Plecoptera: Perlodidae) and their respective species groups using DNA barcoding. Illiesia, 11(11) 130-146. PDF
     Abstract: "We evaluate support for the morphologically based species concepts for 16 western Nearctic Isoperla Banks 1906 species (Plecoptera: Perlodidae) and their respective species groups using the barcode fragment of the mitochondrial gene Cytochrome c Oxidase subunit I (COI) and phylogenetic analyses. Species identifications and assignments to groups were based solely on current morphological species concepts in the literature. COI was sequenced for each species and pairwise genetic distances calculated to understand the magnitude and distribution of genetic variation within this group. COI data were analyzed using both distance (neighbor-joining) and character based (Bayesian inference) phylogenetic approaches. We found for seven morphologically defined taxa that intraspecific genetic variation at COI exceeded the traditional arbitrary 2% sequence divergence threshold sometimes used to delimit species. However, despite these relatively high intraspecific divergence values, we consistently found diagnostic gaps in divergence values between morphologically defined species. Phylogenetic analyses strongly supported the monophyly of all individuals assigned the same species identification based on morphology. Morphological species groups originally proposed by Szczytko & Stewart (1979) were only partially supported with two monophyletic species groups; however, one ambiguous paraphyletic/polyphyletic species group and two polyphyletic species groups were also recovered. Based on current evidence, we propose no changes to the conceptualization of the species groups presented in Szczytko & Stewart (1979) at this time, but rather point out that the present arrangement of species within groups is in need of revision."

Johal,MS; Kumar,M and Rawal,YK 2011 Ultrastructure of adhesive organs of two aquatic insects inhabiting highland hillstreams. Journal of Environmental and Bio-Sciences, 25(1), pp.15-19. PDF
     Abstract: "Primarily to understand the exact mechanism of attachment in the fast flowing torrential water of hillstreams, investigations were carried out to understand the process/mechanism of adhesion in aquatic insects to the wide variety of substrates present in the hillstream Tirthan, in Kullu district of Himachal Pradesh. Two insects i.e. Bibiocephala spp. and Isoperla spp. belonging to order Diptera and Plecoptera, respectively were sampled from the Tirthan stream during summer months (April and May). The SEM investigations of the ventral surface of Bibiocephala spp. revealed the presence of a central row of half-a-dozen distinct suckers having mucous pores in center and surrounded by chitinous pad at posterior end of body. In addition to this, distinct papillae occur on the peripheral region, the tip of which contains long and short hairy pads. In the other aquatic insect Isoperla spp. the ventral surface revealed the presence of numerous inverted bell like structures, which acts as suckers. The action of adhesion is further aided by the presence of spines and hairy fibrils. It is opined that though both insects are living in the same kind of habitat yet both Bibiocephala spp. and Isoperla spp. have different mechanism of adhesion to the substrate."

Peckarsky,BL 1986 Colonization of natural substrates by stream benthos. Canadian Journal of Fisheries and Aquatic Sciences 43, 700-709.

Rader,RB and Ward,JV 1988 Influence of regulation on environmental conditions and the macroinvertebrate community in the upper Colorado River. Regulated Rivers: Research and Management 2:597-618. PDF
     Quote from page 611: "The reference site was represented by a diverse fauna of stoneflies (approximately fiften species) with similar relative abundances. However, only rare individuals of Amphinemura banski), two chloroperlid, and three isoperlid species represented the stonefly taxa at the regulated site. A general reduction in stoneflies and the occasional appearance of Amphinemura and Isoperla is common below dams in Colorado (Ward and Short, 1978; Zimmerman and Ward, 1984). Eight stonefly species were collected at the recovery site; however, only two (Amphinemura banski and Pteronarcella badia) were consistently represented in samples."

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

Robinson,CT and Minshall,GW 1986 Effects of disturbance frequency on stream benthic community structure in relation to canopy cover and season. Journal of the North American Benthological Society, 237-248. PDF
     Abstract: " Field experiments were conducted to examine the effects of disturbance frequency on invertebrates and periphyton colonizing bricks in a third order Rocky Mountain (USA) stream. After an initial colonization period (30 days), sets of bricks were turned over at intervals of 0, 3, 9, 27, or 54 days. Invertebrate species richness and density were reduced as disturbance frequency increased. These trends were evident for both seasons (summer and fall) and sites (open vs. closed canopy). Invertebrate species diversity (H') displayed no effect during the fall experiment; however, H' was reduced at high frequencies of disturbance during the summer experiment. Baetis tricaudatus was the most abundant invertebrate on the substrata at both sites and seasons. Alloperla, Baetis, Cinygmula, Chironomidae, Drunella grandis, Hydropsyche, and Seratella tibialis increased in absolute abundances as disturbance frequency decreased. Four other abundant taxa (Capnia, Cleptelmis, Glossosoma, and Isoperla) displayed no clear response to disturbance in either absolute or relative abundances. Species in low abundance tended to colonize only the less frequently disturbed bricks. During both seasons, periphyton biomass increased as disturbance frequency decreased at the open canopy site, while no trend was apparent at the closed canopy site. Periphyton accumulation monitored over time and among treatments revealed that frequent disturbances maintained low standing crops at an open canopy site. These data suggest that disturbance frequency can directly influence the benthic community at the scale of individual rock "islands" by reducing invertebrate richness, total animal density, and periphyton biomass. The effect of disturbance on species diversity (H') was seasonal, further emphasizing the importance of considering seasonality in stream field studies. "

Roline,R 1988 The effects of heavy metals pollution of the upper Arkansas River on the distribution of aquatic macroinvertebrates. Hydrobiologia 160: 3-8.
     They sampled the Arkansas River upstream and downstream of mine drainage and clean water inputs in 1979 and 1980. After compositing 3 surber samplers in the field, they identified the macroinvertebrates to genus level and used a diversity index to evaluate the health of the macroinvertebrate community. Higher diversity is better. Diversity decreased downstream of heavy metal pollution from the Leadville Drain and California Gulch and increased downstream of clean water inputs.
Quote from page 8: "The plecopterans, Alloperla and Isoperla, were collected at all stations, showing a relative tolerance to heavy metals pollution. "

Sandberg,JB 2011 Vibrational communication of Isoperla Banks from California and Oregon (Plecoptera: Perlodidae). Illiesia 2011 7(1):1-23. PDF

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; Stewart,KW 2001 Drumming behavior and life history notes of a high-altitude Colorado population of the stonefly Isoperla petersoni Needham & Christenson (Plecoptera: Perlodidae). Western North American Naturalist 61 (4) 445-451.

Szczytko,SW and 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 1979b Three new species of nearctic Isoperla (Plecoptera). Great Basin Naturalist 36, 211-220.

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.


Mesosternal Y-arms.
Only visible easily on mature nymphs.