Trichoptera: Lepidostomatidae of Gunnison County, ColoradoIntroduction to the Caddisfly genus Lepidostoma
Lepidostomatid Case Maker Caddisflies, Little Plain Brown SedgeRambur, 1842
Updated 29 Jan 2010
TSN 116793
Provisional Species List
Description
Lepidostoma larvae are small cased larvae found in streams and rivers. The family Lepidostomatidae are identified by the antennae very close to the eye as well as missing the median dorsal hump on segment one of their abdomen. We only have one genus of Lepidostomatidae in the county (Lepidostoma) so that will identify the larvae to genus in our area. The Gunnison Basin larvae I've seen so far have cases of small sand grains, although other species may have cases constructed of plant pieces and could be present in our area. Keys to the larvae have not been developed yet. For adults, see Weaver's publications.
Good Links
On this website:
Species not reported from the county yet but possibly present:
Lepidostoma ormeum (Pitkin County)
Lepidostoma unicolor (Saguache County)
Other Websites:
Photo - of an adult Lepidostomatidae from Alex Wild http://www.myrmecos.net/insects/Lepidostomatid1.html
References
Canton,SP; 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: "Lepidostomatidae (primarily Lepidostoma moneka) was more abundant at C2 (above the mine), comprising 37% of the density of Trichoptera at this site, but only 4% at C4 (below the mine)." They suggest L. moneka is less common below the mine because they are shredders and don't have leaves from the willows and alders to eat.
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
Quote from page 633: "Rhyacophila sp.(Fig.5j) was the only caddisfly that showed a significant response to metal level and was lower at medium-metal sites. Differences among metal catagories in abundance of the three other dominant caddisflies, (Brachycentrus americanus, Hydropsyche sp., and Lepidostoma sp.) and the blackfly Simulium sp. were not significant (Fig. 5g, h, i, k)."
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.
Dodds GS; 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
Kerr,JD and Wiggins,GB 1993 Larval taxonomy in North American Lepidostomatidae. Proceedings of the Seventh International Symposium on Trichoptera, Sweden, 1992, C. Otto (ed.), pp 117-121. Leiden: Backhuys Publishers.
Mihuc,TB; Mihuc,JR 1995 Trophic ecology of five shredders in a Rocky Mountain stream. Journal of Freshwater Ecology 10 3, 209-216.
Peckarsky,BL 1986 Colonization of natural substrates by stream benthos. Canadian Journal of Fisheries and Aquatic Sciences 43, 700-709.
Ross, H. H. 1946 A review of the nearctic Lepistomatidae (Trichoptera). Annals of the Entomological Society of America 39:265-291.
Weaver III, JS. 1983 The evolution and classification of Trichoptera, with a revision of the Lepidostomatidae and a North American synopsis of this family. Ph.D. dissertation, Clemson Univ. Clemson, South Carolina 411 pages.
Weaver III,JS 1988 A synopsis of the North American Lepidostomatidae (Trichoptera). Contributions of the American Entomological Institute 24, 1-141.
Wiggins, GB 1996 Larvae of the North American Caddisfly Genera (Trichoptera). 2nd Edition. University of Toronto Press, 457 pages.
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