Hydropsyche occidentalis (Trichoptera) of Gunnison County, Colorado

Trichoptera: Hydropsychidae of Gunnison County, Colorado

Hydropsyche occidentalis

Banks 1900

Updated 20 February 2024
TSN 115513

Good Links

On this website:
Introduction to Hydropsyche

Other Websites:
Illustration - University of Alberta Entomology Collection Species page
Has description, habitat information, range and more.

North American distribution map - flyfishingentomology.com

References

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

Banks,N 1900. New genera and species of Nearctic neuropteroid insects. Transactions of the American Entomological Society 26:239-260.

Blinn,DW and Ruiter,DE 2006 Tolerance values of stream caddisflies (Trichoptera) in the lower Colorado river basin, USA. The Southwestern Naturalist 51(3):326-337. Abstract

Blinn,DW and Ruiter,DE 2013 Tolerance values and effects of selected environmental determinants on caddisfly (Trichoptera) distribution in northwest and north central Washington, USA. Western North American Naturalist, 73(3), pp.270-294. PDF

Djernæs,M and Sperling,FAH 2012 Exploring a key synapomorphy: correlations between structure and function in the sternum V glands of Trichoptera and Lepidoptera (Insecta). Biological Journal of the Linnean Society, 106: 561-579.

Dosdall,LM 1991 Survival of selected aquatic insects exposed to methoxychlor treatment of the Saskatchewan River system. Water Quality Research Journal of Canada. 26(1) 27-40.

Ellsworth,SD 2000 Influence of substrate size, Cladophora, and caddisfly pupal cases on colonization of macroinvertebrates in Sagehen Creek, California. Western North American Naturalist, pp.311-319. PDF
     Abstract: "Colonization of stream macroinvertebrates onto artificial substrates was examined in Sagehen Creek California, during 1993. Substrate size and presence or absence of pupal cases of the caddisfly Anagapetus (Glossosmatidae) were examined as possible influences on macroinvertebrate colonization. Macroinvertebrates were collected from substrates after 60 d of incubation and identified to the lowest feasible taxonomie unit. Dry weight of the filametous green alga Cladophora also was determined for each substrate.
     A general linear model indicated a significant positive relationship between both substrate size and presence pupal cases on richness (P < 0.001). There was no significant effect of cases on the E5 evenness index, which supports the passive sampling model as a mechanism giving rise to the effect of cases on richness. A multivariate general linear model indicated a significant positive effect of Anagapetus cases on Micrasema bactro, Epeorus, and Rhyacophila sp and of substrate size on Hydropsyche occidentalis and Epeorus. Neither cases nor substrate size had a significant effect on Cladophora density (P > 0.05). There were significant negative correlations between Cladophora density and both Shannon H' and J' indices. There were significant positive relationships between Cladophora density with Baetis, Simulium, and Chironomidae density. Combined main effects of substrate size, Anagapetus pupal cases, and Cladophora have dynamic influences on this macroinvertebrate fauna. This study demonstrates the complex interplay of biotic abiotic factors that determine macroinvertebrate distribution and abundance in this system."

Gerth,WJ; Murphy,CA and Arismendi,I 2023 Caddisfly dives for oviposition: Record-shattering depths and poor life choices in a dammed river system. Freshwater Science 42(1) 104-117.
     Abstract: "Oviposition is a critical step in the life cycles of aquatic insects. Adult caddisflies exhibit a variety of oviposition methods. In some species, females enter freshwaters to oviposit on submerged substrates. Here, we compile information on North American caddisflies that are known to dive and swim to oviposit and have sexually dimorphic leg characteristics that may be adaptations for swimming, diving, or both. We also report unexpected underwater captures of adult females of 3 caddisfly species in Willamette Basin reservoirs in Oregon, USA, including the deepest dive depths ever recorded for adult female caddisflies. From these captures, we note sexually dimorphic leg widening in the species Hydropsyche centra Ross, for the first time, confirm widened mesothoracic leg segments of Hydropsyche occidentalis Banks, 1900 adult females, and note fringes of long hairs on meso- and metathoracic tibiae and basal tarsal segments of Hydroptila argosa Ross, females. We also note fringes of long hairs on the meso- and metathoracic legs of Hydroptila ajax Ross, females from the banks of the Willamette River. The presumed oviposition attempts of caddisflies underwater in large, deep reservoirs suggest that these caddisflies may misinterpret oviposition cues in altered habitats and waste reproductive efforts. Greater understanding of caddisfly oviposition methods and abilities may be important for long-term conservation and restoration efforts supporting biodiversity in freshwater habitats."

Hauer,FR and Stanford,JA 1982 Ecology and life histories of three net-spinning caddisfly species (Hydropsychidae: Hydropsyche) in the Flathead River, Montana. Freshwater Invertebrate Biology 1:18-29.
     They present life history data on the three species H. cockerelli, H. oslari and H. occidentalis in the tailwaters of Hungry Horse Dam. Quotes from the abstract "H. cockerelli and H. oslari were significantly (P < 0.05) more abundant than H. occidentalis at all sampling sites...snip.. H. occidentalis larval appearance and growth occurred approximately six weeks behind H. cockerelli larvae. Thus, most growth occurred at temperatures < 7 degrees C. We concluded that the delayed growth may have contributed directly, in terms of temperature response, to the infrequency of H. occidentalis larvae."

Hauer,FR; Stanford,JA and Ward,JV 1989 Serial discontinuities in a Rocky mountain river. II. Distribution and abundance of trichoptera. Regulated Rivers: Research and Management 3(1) 177-182.
     Abstract: "River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35-90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m-2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m-2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60-80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept. "

Harris,TL and TM Lawrence 1978 Environmental requirements and pollution tolerance of Trichoptera. Environmental Protection Agency Report 600/4-78-063. Environmental Monitoring and Support Laboratory, Cincinnati,OH.

Herrmann,SJ; Ruiter,DE and Unzicker,JD 1986 Distribution and records of Colorado Trichoptera. Southwestern Naturalist 31 4, 421-457.
     They note the habitat for this species is streams and rivers, the altitudinal range is 1085 to 2941m and adult collection dates are 10 June to 1 September. Quote from page 429: "This species altituditnal range overlaps that of H. cockerelli, although H. occident alis occurs in the lowest portions of the plains zone in eastern Colorado. The lowest altitude reported forH. occidentalis outside Colorado by Harris and Lawrence (1978) was 805m. " They list this species as present in Gunnison county.

Jannot,JE; Kerans,BL 2003 Body size, sexual size dimorphism, and Rensch's rule in adult Hydropsychid caddisflies (Trichoptera: Hydropsychidae). Canadian Journal of Zoology 81, 1956-1964.
     The authors measured 21 and 20 museum specimens from a number of locations of Hydropsyche occidentalis preserved in ethanol finding that adult males were 6.01 ± 0.11 mm in length and females were 6.43 ± 0.10 mm in length. They measured length from the center of the head between the eyes to the posterior margin of the 8th segment. More details

Koslucher,DG and Minshall,GW 1973 Food habits of some benthic invertebrates in a northern cool-desert stream (Deep Creek, Curlew Valley, Idaho-Utah). Transactions of the American Microscopical Society, 92(3) 441-452. Abstract

McCullough,DA and Minshall,GW and Cushing,CE 1979 Bioenergetics of lotic filter-feeding insects Simulium spp. (Diptera) and Hydropsyche occidentalis (Trichoptera) and their function in controlling organic transport in streams. Ecology: 60, (3), pp. 585-596. Abstract

Metcalfe,AN; Muehlbauer,JD; Kennedy,TA; Yackulic,CB; Dibble,KL and Marks,JC 2021 Net-spinning caddisfly distribution in large regulated rivers. Freshwater Biology, 66(1)89-01 PDF
     Abstract: "1. Most of the world's large rivers are dammed for the purposes of water storage, flood control, and power production. Damming rivers fundamentally alters water temperature and flows in tailwater ecosystems, which in turn affects the presence and abundance of downstream biota.
2. We collaborated with more than 200 citizen scientists to collect 2,194 light trap samples across 2 years and more than 2,000 river km. Samples contained 16,222 net-spinning caddisfly (Hydropsyche) individuals across six species. We used these data to model the distribution of Hydropsyche throughout the Colorado River Basin in the western U.S.A. to identify the roles of water temperature, flows, and species-specific morphology in determining aquatic species distributions throughout a large arid watershed that has been heavily altered by damming.
3. We predicted that water temperatures would determine Hydropsyche presence and abundance to a greater extent than diel variation in river stage associated with hydropower production. Among many species, adult female Hydropsychids are morphologically adapted to swim to deep-water oviposition sites. We predicted that the presence of this ability would negate the otherwise deleterious effects of high stage change on caddisfly egg mortality.
4. We found that distributions of the two most widespread species, Hydropsyche occidentalis and Hydropsyche oslari (92% of total Hydropsyche captured), were both predicted by water temperatures. However, we also found that the abundance of H. oslari decreased by as much as 10-fold as diel stage change increased, despite the presence of female morphological adaptations for deep-water oviposition. We found sexual dimorphism and evidence for deep-water swimming adaptations in 5/6 species.
5. Our results show that net-spinning caddisflies have species-specific responses to environmental variation and suggest that environmental flows designed to reduce diel stage change and destabilise water temperatures may improve habitat quality for these ubiquitous and important aquatic insects."

Mecom,JO 1972a Feeding habits of Trichoptera in a mountain stream. Oikos 23: 401-407. Abstract and first page
     Abstract: " The gut contents of more than 900 Trichoptera larvae from the St. Vrain River of Colorado were determined by Millipore filter analysis. They ingested a mixed diet of detritus, vascular plants, diatoms and other algae (e.g. Ulothrix). Vascular plant fragments, detritus, and filamentous algae were the major food categories ingested from late spring through early summer, while diatoms were most commonly consumed in mid-winter and early spring. Seasonal dietary changes were apparently related to general availability of organic material and larval microhabitat. Hydropsyche sp., Arctopsyche grandis, Hydropsyche occidentalis and Brachycentrus americanus were predatory or cannibalistic during a brief period from May to August. This carnivorous behavior was not directly correlated either to species crowding or population developmental changes. "

Mecom,JO 1972b Productivity and distribution of Trichoptera larvae in a Colorado mountain stream. Hydrobiologia 40(2): 151 - 176. ISSN: 0018-8158 (Paper) 1573-5117 DOI: 10.1007/BF00016789 Abstract

Mecom,J 1970 Unusual case-building behaviour of Hydropsyche occidentalis larvae (Trichoptera: Hydropsychidae). Entomological News 81:33-35.

Newell,RL and Minshall,GW 1977 An annotated list of the aquatic insects of southeastern Idaho, Part II: Trichoptera. The Great Basin Naturalist, pp.253-257.
     Quote from page : " Individuals of the family Hydropsychidae were the most frequently encountered. Individuals of Hydropsyche occidentalis were extremely abundant in the main Snake River, often visible in swarms of thousands of adults. "

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

Ruse,LP and Herrmann,SJ 2000 Plecoptera and Trichoptera species distribution related to environmental characteristics of the metal-polluted Arkansas River, Colorado. Western North American Naturalist 60 (1) 57-65. PDF
     Quote from page 62: "Although no stoneflies were collected downstream of Pueblo Reservoir, the hydropsychids Cheumatopsyche pettiti and Hydropsyche occidentalis and the hydroptilids Hydroptila ajax and Ochrotrichia stylata were dominant at AR19 and AR20. [downstream of the reservoir]"

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

Brown,WS 2005 Trichoptera of Gunnison County, Colorado, USA
www.gunnisoninsects.org