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Trichoptera or Caddisflies of Gunnison County Colorado

Under Construction - Updated 18 Nov 2018

Introducing the Caddisflies!

On the right we have a common caddisfly called the American Grammon or Brachycentrus americanus to the detail oriented people among us. Notably it builds and carries a square case that looks something like a log cabin. This one was netted from the Gunnison River in March of 2008. They live among the rocks and cobbles in rivers and streams in a community of bottom dwelling stream insects including mayflies, stoneflies, true flies, and of course the ubiquitous beetles.

Other caddiflies contruct a wide variety of cases. Sometimes their distinctive cases allow instant identification and gratification. However, many species make their cases out of a nondescript bunch of leaves, bark or fine gravel, so don't get overconfident. The skills needed to construct caddis cases did not arise until later in the evolution of caddisflies so the most primative caddis do not have cases. For example, check out the Rhyacophilidae or Free Living caddis.

Good Links

There is a caddisfly listserver moderated by John C. Morse. Persons wishing to subscribe to Trichoptera discussion list may send a message to listserv@clemson.edu . Put nothing in the "SUBJECT" line and the body of the text should say:


Other Websites:
Family Key for Europe - from EuTaxa
     While strictly speaking this key is intended for Europe, it works to the family level for many North American families. It has excellent photos and is very helpful if you are not sure about what you're looking at. You can also purchase identification CD's for a variety of European taxa.

Nectopsyche, Neotropical Trichoptera Newsletter http://www.entomology.umn.edu/museum/links/news.html

Trichoptera World Checklist http://entweb.clemson.edu/database/trichopt/

Introduction to Trichoptera from Environmental Statistics Group at Montana State University http://www.esg.montana.edu/dlg/aim/trichop/trichop.html

Wikipedia - Trichoptera or Caddisfly http://en.wikipedia.org/wiki/Caddisfly

PAN Pesticides database: http://www.pesticideinfo.org/List_AquireAll.jsp?Species=259&Effect=

Illinois Natural History Survey (INHS) http://ellipse.inhs.uiuc.edu:591/INHSCollections/trichopterasearch.html
     Try typing Gunnison in the county space and Colorado in the state, then searching. Notice that in their insect collection, they have many unidentified caddisfly specimens collected in our area in 1978.

Here is an unidentified caddisfly adult.


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.

Elmork,K; Saether,OR 1970 Distribution of invertebrates in a high mountain brook in the Colorado Rocky Mountains. University of Colorado Studies Series in Biology No 31.

Herrmann,SJ; Ruiter,DE and Unzicker,JD 1986 Distribution and records of Colorado Trichoptera. Southwestern Naturalist 31 4, 421-457.
     Most of the distribution information in the Trichoptera list for Gunnison County was gleaned from this paper. They report 15 families with 176 species in Colorado.

Mackay,RJ; Wiggins,GB 1979 Ecological diversity in Trichoptera. Annual Review of Entomology 24, 185-208.

Maret,TR; Cain,DJ; MacCoy,DE; Short,TM 2003 Response of benthic invertebrate assemblages to metal exposure and bioaccumulation associated with hard-rock mining in northwestern streams, USA. Journal of the North American Benthological Society 22 4, 598-620.
     Working in the Coeur d'Alene and St Regis river basins of Idaho and Montana, the authors studied a number of stream insects and did tissue analysis of the caddisflies Ceratopsyche spp. Hydropsyche spp. and Actopsyche grandis. They found that cadmium, lead and zinc concentrations were significantly higher in whole body tissue samples of Hydropsychids collected in metal contaminated streams than in the clean reference streams. Cystolic lead was also higher in Hydropsychids from contaminated sites. Quote from page 609: "Metal concentrations in caddisfly tissue were significantly correlated with mine density and metal concentrations in water and sediment."

Morse,JC 1993 A checklist of the Trichoptera of North America including Greenland and Mexico. Transactions of American Entomological Society 119 1, 47-93.

Morse,JC; Holzenthal,RW 1996 Trichoptera Genera. In: An Introduction to the Aquatic Insects of North America. 3rd ed. Eds: Merritt,RW; Cummins,KW Kendall/Hunt Publishing Company, Dubuque, Iowa, 350-386.
     The standard bench reference for identifying caddisflies to genus, works well with Wiggins 1996a, below. Watch for the new edition.

<Peckarsky,BL; McIntosh,AR; Àlvarez,M and Moslemi,JM 2015 Disturbance legacies and nutrient limitation influence interactions between grazers and algae in high elevation streams. Ecosphere, 6(11)1-15. PDF
     Abstract: " Debate about control of interaction strength among species is fueled by variation in environmental contexts affecting food webs. We used extensive surveys and two field experiments to test the individual and interactive influences of variation in the assemblages and associated traits of grazers as shaped by the legacy of disturbance, nutrient limitation and the presence of top predators on the accrual of basal resources. We quantified hydrologic variation and streambed movement to describe the legacy of disturbance and sampled biota of 20 streams over five years in a high-elevation catchment in Colorado, USA. Grazer assemblages switched from caddisfly-dominated to mayfly-dominated as disturbance increased. We manipulated the composition of grazer assemblages and the availability of nutrients (N and P) within flow-through mesocosms assembled adjacent to 10 streams, and also deployed larger in-stream channels manipulating the presence of top predators (brook trout) in five streams varying in disturbance regimes. In both experiments we compared the rate of accrual of benthic algae and the strength of grazer-algal interactions among treatments. We observed no indirect effects of top predators on grazer mobility, grazer consumption of algae, or accrual of algal biomass (no trophic cascades). However, in both experiments accrual rates of algae yielded a unimodal pattern and grazer impacts on algae decreased with increasing disturbance, but only at ambient (limiting) nutrient conditions. When nutrients were amended in the mesocosm experiment, algal accrual was uniformly high and grazer impacts on algae were consistently low. Reduced algae accrual at high disturbance levels may be explained by direct effects of environmental harshness on algae, and at low disturbance by indirect effects on grazer traits (behaviors) rather than on grazer density. In more benign streams per capita and per unit biomass grazer impacts on algae were high and drift dispersal was low, both behaviors that reduced accrual of algae. We conclude that nutrient limitation and indirect effects of disturbance on accrual of algae mediated by grazer traits can be stronger than indirect effects of predators on algae, providing a new contribution to the debate about the influence of environmental context on the strength of food web interactions."

Ross,HH 1944 The Caddis Flies, or Trichoptera, of Illinois. Natural History Survey of Illinois, Los Angeles, CA. 326 pages.

Ross,HH 1967 The evoution and past dispersal of the Trichoptera. Annual Review of Entomology 12, 169-207.

Wiggins, GB 1996a Larvae of the North American Caddisfly Genera (Trichoptera). 2nd Edition. University of Toronto Press, 457 pages.
     The essential North American caddisfly larvae key. Technical, not a field guide, intended for use at a bench with a microscope. Has full body larval illustrations as well as cases and taxonomically important details. Mentions life history and further papers to read about each genus. Also briefly discusses taxonomic questions or problems for some genera.

Wiggins,GB 1996b Trichoptera Families. In: An Introduction to the Aquatic Insects of North America. 3rd ed. Eds: Merritt,RW; Cummins,KW Kendall/Hunt Publishing Company, Dubuque, Iowa, 309-349.
     The standard bench reference for identifying aquatic insects. The chapter on caddisfly families is a synopsis of Wiggins' book mentioned above. Watch for a new edition.

Brown, Wendy S. 2004 Trichoptera of Gunnison County, Colorado, USA