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Trichoptera of Gunnison County, Colorado

Introduction to the caddisfly family Hydropsychidae

Common Net Spinner Caddis, Cinammon Caddis, Light wing medium brown body caddis #16-20, Light wing tan body caddis #18-20, Medium wing tan body caddis #16-22, Spotted Sedge

Curtis, 1835

Updated 7 January 2018

This Hydropsychidae retreat was under a rock in a tributary of the East River on 18 July 2007. Notice the net they use for gathering food. The top of the Hydropsychidae's head is visible right of the net. Notice the abdomen of a Cinygmula larvae under the upper right of the retreat.

Provisional Species List


Larvae are large in their last instars. They may be the biggest animals in your pan of bugs from a kick sample. Hydropsychid larvae live under rocks in most streams and rivers in Gunnison County, building a retreat (or house) and spinning a net to capture detritus and small invertebrates.
Adults are diverse in size, shape and taxonomic characteristics. Both sexes have a 5-segmented maxillary palp. All genera lack scutal warts, ocelli and preapical spurs on their front tibia (Ross, 1944).

Life History

Adults females lay eggs underwater in strings attached to submerged rocks or other objects. The eggs are in a cement-like matrix (Ross, 1944)

Good Links

Other Websites:
Family Overview - University of Alberta Entomology Collection Family page
     Has habitat, identification, life history, conservation and more.


Allan,JD 1987 Macroinvertebrate drift in a Rocky Mountain stream. Hydrobiologia 144, 261-268.
     Working in Cement Creek, Allan looked at aquatic insects drifting in the water column for 24 hour time periods during the summers of 1976 and 1977. On page 263, he briefly says "Trichoptera (mostly several species of Rhyacophila, but occasional Hydropsychidae and Brachycentrus americanus Banks) always exhibited very low drift densities."

Alstad,DN 1980 Comparative biology of the common Utah Hydropsychidae (Trichoptera). American Midland Naturalist 103, 167-174.

Banks,N 1905 Descriptions of new neuropteroid insects. Transactions of American Entomological Society 32, 1-20.
     Has descriptions of several of the local Hydropsychidae species.

Canton,SP and Ward,JV 1981 The aquatic insects, with emphasis on Trichoptera, of a Colorado stream affected by coal strip-mine drainage. Southwestern Naturalist 25 4, 453-460.
     They studied Trout Creek where it runs through the Edna Coal Mine in northwestern Colorado. The mine spoils were 30 meters from the edge of the creek (approximately a 100 foot buffer zone). They found the aquatic insect density (numbers per square meter) and biomass (weight in grams per square meter) did not change above and below the mine. The Shannon-Weaver Diversity index also showed no difference between sites. However the community structure (which species were present and proportions) did change. Since there were irrigation water and cattle influences at their downstream site, their results may reflect these additional water uses. They note the biggest visible change at this mine is the loss of willow and alder trees downstream of the mine. The caddisfly population changed the most between sites, shifting from a mix of families above the mine to dominance by Hydropsychidae and Glossosomatidae below the mine.
Quote from page 457: "The Hydropsychidae (Arctopsyche inermis, Hydropsyche cockerelli, and H. oslari) were unimportant at C2 (reference site), comprising only 3% of trichopteran numbers, while at C4 (mine affected), with increased abundance of Hydropsyche spp., they accounted for 16% of the density."

Clements,WH; Carlisle,DN; Lazorchak,JM; Johnson,PC 2000 Heavy metals structure benthic communities in Colorado mountain streams. Ecological Applications 10(2)626-638. Abstract

Clements,WH; Cherry,DS; Cairns,J 1988 Impact of heavy metals on insect communities in streams: a comparision of observational and experimental results. Canadian Journal of Fisheries and Aquatic Sciences 45 11, 2017-2025.
     Working in the Clinch River of Russell County, Virginia and outdoor experimental streams, they measured population responses of macroinvertebrates to natural conditions and 12 µg of copper and zinc in the artifical streams. They used 6 replicates of substrate-filled trays everywhere and counted all the animals (no subsampling). Both stream mesocosm experiments and Clinch river sites showed similar results. They found abundance or total numbers of aquatic insects declined at all high effluent sites associated with the Clinch River coal-fired power plant, recovering 3- 4 kilometers downstream. Low levels of copper and zinc reduced species richness (number of different taxa) and total numbers as well as caused a shift in the species composition of dominant taxa. Metal contamination caused macroinvertebrate populations to shift from control (clean) sites dominated by Mayflies and Tanytarsini Midges to polluted sites dominated by Hydropsychidae caddisflies and Orthocladiinae midges.

Coutant,CC 1982 Evidence for upstream dispersal of adult caddisflies (Trichoptera: Hydropsychidae) in the Colombia River.Aquatic Insects 4:61-66

Curtis,J 1835 British Entomology being Illustrations and Descriptions of the Genera of Insects found in Great Britain and Ireland Containing Coloured Figure from Nature of the Most Rare and Beautiful Species, and in Many Instances of the Plants Upon Which They are Found. Richard Taylor, London. vol. XII, 530-577.

Deutsch,WG 1985 Swimming modifications of adult female Hydropsychidae compared with other Trichoptera. Freshwater Invertebrate Biology, 4(1) 35-40.

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

Elliot,AG; Hubert,WA; Anderson,SH 1997 Habitat associations and effects of urbanization on macroinvertebrates of a small, high-plains stream. Journal of Freshwater Ecology 12 1, 61-73.

Fairchild,MP and Holomuzki,JR 2005. Multiple predator effects on microdistributions, survival, and drift of stream hydropsychid Caddisflies. J. NABS 24: 101-112.

Gray,LJ and Ward,JV 1979 Food habits of stream benthos at sites of differing food availability. American Midland Naturalist 102 1, 157-167.

Kiffney,PM 1996 Main and interactive effects of invertebrate density, predation and metals on a Rocky Mountain stream macroinvertebrate community. Canadian Journal of Fisheries and Aquatic Sciences 53 7, 1595-1601.

Nimmo,AP 1987 The adult Arctopsyche and Hydropsyche (Trichoptera) of Canada and adjacent United States. Questiones Entomologicae 23:1-189.

Nimmo,AP 1995 New species of Hydropsychidae and Limnephilidae (Insecta, Trichoptera) from the far east of Russia, with description of a new genus of Limnephilidae (Limnephilini). Occasional Papers on Trichoptera Taxonomy 1, 1-15.

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

Ross,HH 1944 The Caddis Flies, or Trichoptera, of Illinois. Natural History Survey of Illinois 23 Los Angeles, CA. 326 pages.
     Contains keys to genera for adult Hydropsychidae.

Rutherford,JE and MacKay,RJ 1985 The vertical distribution of hydropsychid larvae and pupa (Trichoptera: Hydropsychidae) in stream substrates. Canadian Journal of Zoology 63:1306-1315.

Schefter, Patricia W. 2005 Re-evaluation of genera in the subfamily Hydropsychinae (Trichoptera: Hydropsychidae). Aquatic Insects 27(2) 133 - 154. Abstract

Voelz,NJ; Poff,NL and Ward,JV 1994 Differential effects of a brief thermal disturbance on caddisflies (Trichoptera) in a regulated river. American Midland Naturalist 132 1, 173-182.

Voelz,NJ and Ward,JV 1996 Microdistributions, food resources and feeding habits of filter-feeding Trichoptera in the Upper Colorado River. Archiv fur Hydrobiologie 137 3, 325-348.

Warnick,SL and Bell,HL 1969 The acute toxicity of some heavy metals to different insects. Journal WPCF 41 2, 280-284.

Wiggins, GB 1996 Larvae of the North American Caddisfly Genera (Trichoptera). 2nd Edition. University of Toronto Press, 457 pages.
     A key to genera starts on page 128. Wiggins states that there are 145 species in 10 genera in North America.

Zuellig,RE; Kondratieff,BC and Rhodes,HA 2002 Benthos recovery after an eposodic sediment release into a Colorado Rocky Mountain river. Western North American Naturalist 62 1, 59-72.

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Brown,WS 2005 Trichoptera (Caddisflies) of Gunnison County, Colorado, USA