Stoneflies - Plecoptera: Taeniopterygidae of Gunnison County, Colorado
Taenionema pacificum Pacific Willowfly(Banks) 1900
Updated 20 Jan 2021
DescriptionThese insects vary regionally in the branching of wing veins as well as details of size and shape of the lobes on tergum 10, which translated means they're variable and sometimes hard to identify.
HabitatLarger streams and Rivers 1600 to 2800 meters elevation (Kondratieff and Baumann (2002).
Life HistoryPeak emergence is March to May, but later at high elevations in the United States and Canada (Stanger and Baumann, 1993). This species is widely distributed in North America, adults may be collected from mid February to early July. Adults are often found on Salix spp (willow).
Locations CollectedIn Colorado, T. pacificum is more common west of the continental divide (Kondratieff and Baumann 2002). Stanger and Baumann (1993) show adults have been collected in Gunnison County from the Gunnison River at Soap Creek, Lake Fork of the Gunnison as well as Cimmarron Creek in Montrose County. Stark et al 1973 records specimens from Soap Creek, Lake Fork Gunnison River, Sapinero Creek, and Quartz Creek.
NotesStanger and Baumann (1993) comment that there were several sources reporting T. pacificum damaged fruit trees in Washington and Oregon in the early part of the 20th century. They also reported a specimen had eaten Medicago. Older publications may refer to this species as Taeniopteryx pacificum.. Brachyptera (subgenus Taenionema) pacifica is a synonym used in Stark et al 1973. Both genus and species name-ending changed from feminine to neuter (or -a to -um and -is to -e) in the mid 1970s after George Steyskal pointed out the details of the Greek root of the word Taenionema (Steyskal, 1976).
Good LinksOn this website:
Key to Taenionema Females
Key to Taenionema Males
Photos, Map, Museum specimens, DNA - Barcodinglife.org
Photo - Nymph from Michael Wigle Photography. Nymph again
ReferencesBanks,N 1900 New genera and species of Nearctic Neuropteroid Insects. Transactions of the American Entomological Society 26:239-259.
Described as Taeniopteryx pacifica
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 53: "This species is found primarily in rivers in the north but also occurs in streams in the southern part of its range. The adults emerge from March to July."
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 393: "This species is characteristic of larger streams ans rivers throughout the Mountain and Plateau regions of Colorado, usually found at elevations between 1,600-2,800 m. However, it appears to be much more common west of the Continental Divide. Apparently, it occurred historically in several large Front Range streams."
Needham,JG and Claassen,PW 1925 A Monograph of the Plecoptera of North America. Entomological Society of America, Lafayette, Indiana. 397 pages.
Described as Taeniopteryx pacifica.
Short,RA; Canton,SP and Ward,JV 1980 Detrital processing and associated macroinvertebrates in a Colorado mountain stream. Ecology, 61(4), 727-732. PDF
Taenionema nymphs were found in all 4 of the plant species used to make leaf packs; alder, willow, aspen and pine.
Stanger,JA; Baumann,RW 1993 A revision of the stonefly genus Taenionema (Plecoptera: Taeniopterygidae). Transactions of the American Entomological Society 119(3) 171-229.
A complete diagnosis may be found on page 192 with illustrations on page 225. They discuss regional variation in the size and shape of the lobes on tergum 10 and in the number of branches in the radial sector of the wing. Colorado specimens are larger, have larger quadrate lobes on tergum 10, a rounded epiproct and three to four branches in the radial sector of the wing. Both sexes are macopterous and have heavily sclerotized mandibles and a number of other mouthparts adapted for eating as an adult.
Stark,BP; Oblad,BR; Gaufin,AR 1973 An annotated list of the Stoneflies (Plecoptera) of Colorado Part I. Entomological News 84 (9) 269-277.
Discussed as Brachyptera (subgenus Taenionema) pacifica.
Stewart,KW 2009 New descriptions of North American Taenionema larvae (Plecoptera: Taeniopterygidae). Illiesia 5(12):128-145. 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 239-240, figures 10.9-10.10
Steyskal, GC 1976 Notes on the nomenclature and taxonomic growth of the Plecoptera. pp 408-410. In: A report on the fifth international symposium on Plecoptera. RW Baumann, ed. Proc. Biol. Soc. Wasington. 88:399-428.
Brown,WS 2004 Plecoptera or Stoneflies of Gunnison County, Colorado