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Stoneflies - Plecoptera: Perlodidae

Isogenoides elongatus - Elongate Springfly

(Hagen, 1874)
Updated 20 September 2020
TSN 103130


Nymphs live under stones in riffles.

Life History

Richardson and Gaufin found this species was carnivorous - 65% animal matter, 35% plant material in gut contents. They ate mostly smaller animals such as Simuliidae (black fly) and Chloroperlidae larvae. Ephemeroptera (mayflies) and Trichoptera (cadisflies) were found in smaller numbers.

John Sandberg has posted a wav file (1624 KB) and a mov file (long download over a dialup connection) of I. elongatus drumming on his website.

Locations Collected

Slate River, Lake Fork


Older publications may refer to this species as Isogenus elongatus.

Good Links

On this website:
Key to Perlodidae Nymphs
Introduction to Isogenoides

Other Websites:
Drumming - from Jon Sandburg's website


Baumann,RW, Gaufin,AR and Surdick,RF 1977 The stoneflies (Plecoptera) of the Rocky Mountains. Memoirs of the American Entomological Society 31, 1-208.
     Quote from page 127: " This species is often associated with Isogenoides colubrinus. It is common in rivers and large creeks. The adults emerge from May to July. "

Corkum LD and Clifford HF 1980 The importance of species associations and substrate types to behavioural drift. Pages 331-341 in Flannigan JF; Marshall KE. Advances in Ephemeroptera Biology. Plenum Press, New York. PDF

Corkum LD and Clifford HF 1981 Function of caudal filaments and correlated structures in mayfly nymphs, with special reference to Baetis (Ephemeroptera). Quaestiones Entomologicae 17:129-146. PDF

Hagen,HA 1874 Report on the Pseudo-neuroptera and Neuroptera collected by Lieut. W.L. Carpenter in 1873 in Colorado. Annual Report of the U.S. Geological and Geographical Survey of the Territories, embracing Colorado, 7: 571-577.
     Described as Isogenus elongatus.

Klapálek, Frantisek 1912 Plécoptères. I. Fam. Perlodidae; [monographische Revision. II. Fam. Perlidae; Subfam. Perlinae, Subfam. Neoperlinae; mongraphische Revision] Series Sélys-Longchamps, Edmond de, baron, 1813-1900. Collections zoologiques; catalogue systematique et descriptif, fasc. 4, pt. 1-2.
     Discussed as Isogenoides elongatus.

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 the American Entomological Society 128 (3) 385-401.
     Quote from page 397: "Historically, this species occurred in several Front Range rivers, such as the Cache la Poudre and South Platte, but has apparently been extirpated by irrigation practices and pollution. This species is common in the midlle portion of the Colorado River (Eagle and Garfield counties) and the Gunnison River (Delta Co.), and can be found in the larger streams of the Mountain and Plateau regions. "

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

Sandberg,JB and Stewart,KW 2004 Capacity for extended egg diapause in six Isogenoides Klapálek species (Plecoptera: Perlodidae). Transactions of the American Entomological Society 130(4): 411-423.
     Abstract: "The eggs of six Isogenoides species have been incubated at a single, approximately simulated, San Miguel River, Colorado, seasonal temperature regime for 2-5 years. Eggs were collected from reared, laboratory-mated females of I. colubrinus, I. doratus, I. elongatus, I. frontalis, I. varians, and I. zionensis. Eggs were held in 8 ml containers and visually examined usually weekly for development and hatch. Only some I. zionensis eggs from a combined first and second mass of a Leopard Creek, Colorado population hatched directly within two weeks, continuing until late September, and resuming mainly May-June the following year; one and two eggs hatched in 2002 and 2004, respectively. I. doratus and I. varians experienced hatch only after an over-summer, 3-4 month diapause, and I. varians again in late August-September during the second year. Populations of I. colubrinus, I. elongatus, I. frontalis and a San Miguel River, Colorado population of I. zionensis began hatching only in the year following deposition, after a 10-12 month diapause. Some hatching of these four species occurred at spring-summer temperatures in subsequent years (2nd, 3rd, 3rd, and 4th years, respectively), with no intervening hatch at winter temperatures. The study confirms extended, usually asynchronous diapause and hatching for from 3 months to 4 years, probably genetically controlled, in the six species, and a great degree of adaptive capacity for diapause in the genus Isogenoides."

Sandberg,JB and Stewart,KW 2005a Vibrational communication (Drumming) of the nearctic stonefly genus Isogenoides (Plecoptera:Perlodidae). Transactions of American Entomological Society 131 1+2, 111-130. PDF

Sandberg,JB and Stewart,KW 2005b Holomorphology and systematics of the stonefly genus Isogenoides (Plecoptera: Perlodidae). Transactions of the American Entomological Society 131 3+4, 269-345.

Stewart,KW and Zeigler,DD 1984 Drumming behavior of twelve North American stonefly (Plecoptera) species: First descriptions in Peltoperlidae, Taeniopterygidae and Chloroperlidae. Aquatic Insects. 6(1) 49 - 61. Abstract
     Part of abstract: " "

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 54:"Isogenoides elongatus is distributed throughout the Western mountain states and can be relatively common in large rivers west of the continental divide in Colorado (Sandberg and Stewart, 2005). Apparently it was historically present along the plains mountain interface in large tributaries of the SPRB (Hanson, 1943; Kondratieff and Baumann, 2002). Hagen (1874) described this species from "Foot-hills, Colorado (Mr. Carpenter)." Hanson (1943) indicated that the original description by Hagen (1874) was unrecognizable and redescribed the male from specimens from "Platte Canyon" and "Poudre River" in Colorado. Baumann and others (1977) indicated a record from Boulder County; it probably is the same record from Stark and others (1973b). Apparently, this species has been eliminated from its historical locations along the Front Range of the SPRB as specimens have not been reported from the basin since 1889 (Kondratieff and Baumann, 2002)."

Brown, WS 2004 Plecoptera of Gunnison County, Colorado