Trichoptera: Lepidostomatidae of Gunnison County, Colorado
Introduction to the Caddisfly genus LepidostomaRambur, 1842
Lepidostomatid Case Maker Caddisflies, Little Plain Brown Sedge
Updated 8 Feb 2017
Provisional Species List
Lepidostoma larvae are small cased larvae found in streams and rivers. The family Lepidostomatidae are identified by their antennae being very close to the eye as well as missing the median dorsal hump on their first abdominal segment. We only have one genus of Lepidostomatidae, Lepidostoma in the county. 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.
On this website:
Species not reported from the county yet but possibly present:
Lepidostoma ormeum (Pitkin County)
Lepidostoma unicolor (Saguache County)
Adult Photo - by Tom Murray Lepidostoma adult
Brinkman,SF and Johnston,WD 2012 Acute toxicity of zinc to several aquatic species native to the Rocky Mountains. Archives of environmental contamination and toxicology, 62(2), 272-281.
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: "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. PDF
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)."
Cummins,KW; Wilzbach,MA; Gates,DM; Perry,JB; Taliaferro,WB 1989 Shredders and riparian vegetation. BioScience, 39(1), 24-30. 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.
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
Gaufin,AR; Clubb,R and Newell,R 1974 Studies on the tolerance of aquatic insects to low oxygen concentrations. Great Basin Naturalist 34:45-59. PDF
The authors studied the acute short term tolerance of aquatic insects to low oxygen. They used the 96 hour Median Tolerance Limit. They did not find a TLm96 for Lepidostoma sp.. The authors had 80% survival from 3-4 mg/l of oxygen with their experimental apparatus.
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. PDF
Abstract: " The trophic ecology of five shredder taxa found in Mink Creek, Idaho was determined in laboratory food quality experiments to assess the obligate or facultative nature of resource utilization among lotic taxa commonly referred to as detritivores. The experiments tested resource assimilation for each taxon among three major resources available to primary consumers in streams; periphyton, fine particulate detrital material (FPM) and coarse particulate detrital material (CPM). Growth of each taxon was determined on each resource in laboratory experiments conducted at 10° C.
Growth results indicate that only one of the five taxa (middle-late instar Dicosmoecus atripes) was an obligate CPM detritivore. The remaining four taxa (Amphinemura banksi, Lepidostoma sp., Podmosta delicatula, and Zapada cinctipes) were generalists capable of growth on at least two of the three resource types. All four generalists exhibited growth on periphyton and CPM resources suggesting that these taxa can utilize both autochthonous and allochthonous resources. Our results do not support the idea that taxa with similar mouthpart morphology, specifically shredders, exhibit similar trophic relationships."
Peckarsky,BL 1986 Colonization of natural substrates by stream benthos. Canadian Journal of Fisheries and Aquatic Sciences 43, 700-709.
Rambur,JP 1842 Histoire naturelle des insects néveroptères. - Libairie Encyclopédique de Roret, Paris, xviii + 534 p.
Ross, HH 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.
Weaver III,JS 2002 A synonymy of the caddisfly genus Lepidostoma Rambur (Trichoptera: Lepidostomatidae), including a species checklist. Tijdschrift voor Entomologie, 145(2), 173-192. PDF
Wiggins, GB 1996 Larvae of the North American Caddisfly Genera (Trichoptera). 2nd Edition. University of Toronto Press, 457 pages.