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Trichoptera: Glossosomatidae of Gunnison County, Colorado

Introduction to the caddisfly genus Glossosoma
Saddle Case Makers, Tortoise Case Makers, Turtle Case Makers, medium brown body cadddis #14-18, Little Tan Short-horn Sedge

Curtis 1834

Updated 11 Nov 2015
TSN 117159
Glossosomatidae cases just above the water line in a small stream.
These Glossosomatidae cases
were seen just above the water line
in a small tributary of the East River near Gothic, CO

Provisional Species List

Glossosoma parvulum
Glossosoma verdona

Good Links

On this website:
Agapetus boulderensis

Other Websites:
Photos - from bugguide.net


Banks,N 1904 Neuropteroid insects from New Mexico. Transactions of American Entomological Society 32, 97-110.

Banks,N 1911 Descriptions of new species of North American Neuropterid Insects. Transactions of American Entomological Society 37, 335-360.

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: "Glossosomatids (Glossosoma ventrale and Agapetus boulderensis) were abundant at both locations. At C2 (upstream of mine) the comprised 33% of the trichopterans; at C4 (below the mine) they clearly dominated the caddisfly community with increased abundance of both species, and accounted for 64% of the density."

These Glossosomatidae pupal cases
are firmly attached to the bottom of a rock.
They live in streams and rivers throughout the area.

Curtis, J. 1834. Descriptions of some hitherto nondescript British species of mayflies of anglers. The London and Edinburgh Philosophical Magazine and Journal of Science 3:212-218.

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.

Djernæs,M 2011 Structure and phylogenetic significance of the sternum V glands in Trichoptera Zootaxa 2884: 1-60.
     Abstract: "I investigated the sternum V gland in 38 families of Trichoptera, and found it to be present in 25 of these. I found that the gland is generally present in Annulipalpia, except Dipseudopsidae, and in Spicipalpia. It is widespread in Plenitentoria, while it is often absent in Brevitentoria, especially in males. The opening is slit-like and U or crescent-shaped. There is significant variation in the cuticular structures associated with the opening ranging from no apparent modification, over scaly patches to elaborate protuberances. Gland opening muscles are associated with the gland in all families except Psychomyiidae, and are divided into 2 distinct types: One originating on the front edge of sternum VI found in Philopotamidae, Rhyacophilidae, Glossosomatidae and Hydroptilidae; and 1 originating on the cuticle of sternum V found in all other trichopterans. The shape of the gland reservoir is variable, from round periform to reniform, elongate or compartmentalised. Muscle fibres are often associated with the reservoir, but are notably absent in Limnephilidae. I mapped characters based on gland structures on a phylogeny of Trichoptera, and discuss the results. The sternum V gland provides potentially important characters from the superorder to the species leve l. I discuss 2 cases where characters from the sternum V gland may solve existing phylogenetic and taxonomic puzzles: Delimitation of Dipseudopsidae versus Polycentropodidae and the relationships among the hydropsychid subfamilies. "

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

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

Morse, John C. and Lianfang Yang 2004 The world subgenera of Glossosoma Curtis (Trichoptera:Glossosomatidae), with a revision of the chinese species of Glossosoma subgenera synafophora Martynov and protogossa Ross. Proceedings of the Entomological Society of Washington: Vol. 106, No. 1, pp.52-73. Abstract

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

Rader RB and Ward JV. 1988 Influence of regulation on environmental conditions and the macroinvertebrate community in the upper Colorado River. Regulated Rivers: Research and Management 2:597-618. PDF
     Quote from page 611 and 612: "The reference site was represented by twelve species of caddisflies, including relatively abundant populations of Arctopsyche grandis and Rhyacophila acropedes. Trichopterans at the regulated site, however, were represented by nine rare and three slightly more abundant caddisflies (Hydroptila sp., Brachycentrus americanus, and Hesperophylax designatus). The abundance of net-spinning caddisflies was significantly reduced in the regulated site compared to both reference and recovery locations (p=0.05), as has been reported by several workers (Armitage and Capper, 1976; Müller, 1962; Ward, 1987).
The thirteen species of Trichoptera in the recovery site included four of the most abundant species of macroinvertebrates at that site: Glossosoma ventrale, Brachycentrus americanus, Lepidostoma ormeum, Oligophlebodes minutes. Ward (1987) summarized the effects of regulation on Trichoptera in Rocky Mountain streams and concluded that Rhyacophila and Hydropsyche were the only genera commonly occurring at both regulated and reference locations, whereas Brachycentrus, Glossosoma, Arctopsyche, and Lepidostoma were often reduced or absent in regulated segments. With the expection of Brachycentrus americanus, which was significantly more abundant in the regulated and recovery sites, compared to the reference site (p=0.05), data from this study concur with previous conclusions concerning the influence of reguation on Trichoptera (Ward, 1987). "

Robinson,CT and Minshall,GW 1986 Effects of disturbance frequency on stream benthic community structure in relation to canopy cover and season. Journal of the North American Benthological Society, 237-248. PDF
     Abstract: " Field experiments were conducted to examine the effects of disturbance frequency on invertebrates and periphyton colonizing bricks in a third order Rocky Mountain (USA) stream. After an initial colonization period (30 days), sets of bricks were turned over at intervals of 0, 3, 9, 27, or 54 days. Invertebrate species richness and density were reduced as disturbance frequency increased. These trends were evident for both seasons (summer and fall) and sites (open vs. closed canopy). Invertebrate species diversity (H') displayed no effect during the fall experiment; however, H' was reduced at high frequencies of disturbance during the summer experiment. Baetis tricaudatus was the most abundant invertebrate on the substrata at both sites and seasons. Alloperla, Baetis, Cinygmula, Chironomidae, Drunella grandis, Hydropsyche, and Seratella tibialis increased in absolute abundances as disturbance frequency decreased. Four other abundant taxa (Capnia, Cleptelmis, Glossosoma, and Isoperla) displayed no clear response to disturbance in either absolute or relative abundances. Species in low abundance tended to colonize only the less frequently disturbed bricks. During both seasons, periphyton biomass increased as disturbance frequency decreased at the open canopy site, while no trend was apparent at the closed canopy site. Periphyton accumulation monitored over time and among treatments revealed that frequent disturbances maintained low standing crops at an open canopy site. These data suggest that disturbance frequency can directly influence the benthic community at the scale of individual rock "islands" by reducing invertebrate richness, total animal density, and periphyton biomass. The effect of disturbance on species diversity (H') was seasonal, further emphasizing the importance of considering seasonality in stream field studies. "

Ross, HH 1956 Evolution and classification of the mountain caddisflies. University of Illinois Press, Urbana, 213 pages.

The United States Geological Survey (USGS) National Water Quality Assessment Data Warehouse (NAWQA) shows this genus present in Gunnison County. Data as of 1Sep2005

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

Wiggins, GB 1996 Larvae of the North American Caddisfly Genera (Trichoptera). 2nd Edition. University of Toronto Press, 457 pages.

Wymer,D; Morse,JC 2000 Larvae, pupae and adults of Glossosoma nigrior (Trichoptera: Glossosomatidae), with a review of the eastern North American species of Glossosoma. Entomological News 111 3, 149-158.

Brown,WS 2004 Trichoptera of Gunnison County, Colorado, USA