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Trichoptera: Rhyacophilidae of Gunnison County, Colorado

Rhyacophila brunnea
Green Rock Worms

Banks 1911
Updated 26 July 2017
TSN 115151


Green when alive although color fades to white in ethanol. Anal proleg lacks apical-lateral spine or spur. Clumps of long branched filamentous gills on the abdomen are easily seen in the field on medium to large larvae.

Locations Collected

Common in the East River, Coal Creek and tributaries. The Illinois Natural History Survey (INHS) Database shows this species present at "Parlin at US 50". Allan (1975) reports this species from Cement Creek.

Good Links

On this website:
Rhyacophila acropedes
Introduction to Rhyacophila

Other Websites:
Photos, Map, Museum specimens, DNA - Barcodinglife.org


Allan,JD 1975 The distributional ecology and diversity of benthic insects in Cement Creek, Colorado. Ecology 56:1040-1053. PDF

Banks,N 1911 Descriptions of new species of North American Neuropterid Insects. Transactions of American Entomological Society 37, 335-360.
     Banks describes this species for the first time.

Banks,N 1914 American Trichoptera - notes and descriptions. Canadian Entomologist 46:149-156, 201-204, 252-258, 261-268.
     Described as R. acropedes, considered a synonym of R. brunnea by Smith and Manual, 1984 (see below).

Buchwalter,DB; Cain,DJ; Clements,WH and Luoma,SN 2007 Using biodynamic models to reconcile differences between laboratory toxicity tests and field biomonitoring with aquatic insects. Environmental Science and Technology 41, 4821-4828.
     Abstract: "Aquatic insects often dominate lotic ecosystems, yet these organisms are under-represented in trace metal toxicity databases. Furthermore, toxicity data for aquatic insects do not appear to reflect their actual sensitivities to metals in nature, because the concentrations required to elicit toxicity in the laboratory are considerably higher than those found to impact insect communities in the field. New approaches are therefore needed to better understand how and why insects are differentially susceptible to metal exposures. Biodynamic modeling is a powerful tool for understanding interspecific differences in trace metal bioaccumulation. Because bioaccumulation alone does not necessarily correlate with toxicity, we combined biokinetic parameters associated with dissolved cadmium exposures with studies of the subcellular compartmentalization of accumulated Cd. This combination of physiological traits allowed us to make predictions of susceptibility differences to dissolved Cd in three aquatic insect taxa: Ephemerella excrucians, Rhithrogena morrisoni, and Rhyacophila sp. We compared these predictions with long-term field monitoring data and toxicity tests with closely related taxa: Ephemerella infrequens, Rhithrogena hageni, and Rhyacophila brunnea. Kinetic parameters allowed us to estimate steady-state concentrations, the time required to reach steady state, and the concentrations of Cd projected to be in potentially toxic compartments for different species. Species-specific physiological traits identified using biodynamic models provided a means for better understanding why toxicity assays with insects have failed to provide meaningful estimates for metal concentrations that would be expected to be protective in nature. "

Dobrin,M and Giberson,DJ 2004 Life history and production of mayflies, stoneflies, and caddisflies (Ephemeroptera, Plecoptera, and Trichoptera) in a spring-fed stream in Prince Edward Island, Canada: evidence for population asynchrony in spring habitats? Can. J. Zool./Rev. Can. Zool. 81(6): 1083-1095. PDF
     Has life history for R. brunnea from Prince Edward Island spring brooks. Quote from pages 1092-1093: "Rhyacophila brunnea Banks (Rhyacophilidae) larvae in Balsam Hollow Brook apparently needed 2 years to complete their life cycle. A range of size classes was collected on most sampling dates, but two clear cohorts were present on several dates (Fig. 5). Recruitment began in midsummer, and larvae grew slowly; pupation and emergence began in the spring - early summer of their second year. Both recruitment and emergence were extended, occurring over several months. Smith (1968) reported that this species (listed as Rhyacophila acropedes Banks) overwinters as third- or fourth-instar larvae in New England and Labrador, with pupation occurring from late May to June and emergence from late July to early August."

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 2012 to 3261m and adult collection dates are 2 April to 6 September. Quote from page 450: "This rhyacophilid is abundant in Colorado throughout its altitudinal range. Smith and Manual (1984) synonymized R. acropedes Banks 1914 with R. brunnea. All Colorado records before 1984 would be listed as R. acropedes "

Mecom,JO 1972 Productivity and distribution of Trichoptera larvae in a Colorado mountain stream. Hydrobiologia 40(2): 151 - 176. ISSN: 0018-8158 (Paper) 1573-5117 (Online) DOI: 10.1007/BF00016789 Abstract
     Discusses this species as R. acropedes. Has life history data from the St Vrain River in Colorado.

Myers,MJ and Resh,VH 2002 Trichoptera and other macroinvertebrates in springs of the Great Basin: species composition, richness, and distribution. Western North American Naturalist 62(1) 1-13. PDF
     Quote from page 6: "We collected a total of 58 different species in 14 different families of caddisflies (Table 5). Four to 18 species were found in a spring. Several springs had very similar physicochemical characteristics; however, none had identical trichopteran composition. Although Lepidostoma cascadense and Rhyacophila brunnea were restricted to cold springs, they were collected from the most springs (12 each). Lepidostoma rayneri, L. roafi, and L. unicolor were also frequently collected (10, 8, and 7 springs, respectively). Across the region (including all 170 springs surveyed), Hesperophylax designatus was the most commonly encountered caddisfly. It was found in temporary springs, springs impacted by grazing, very cold springs at high elevations, and a few of the warmer (14°C), low-elevation springs. Of the 28 springs intensively studied, it was present in 11."

Peckarsky,BL 1980 Influence of detritus on colonization of stream invertebrates. Canadian Journal of Fisheries and Aquatic Sciences 37, 957-963. Abstract
     Discusses this species as R. acropedes, present in the East River near Gothic.

Peckarsky,BL; Dodson,SI and Conklin,DJ 1985 A key to the aquatic insects of streams in the vicinity of the Rocky Mountain Biological Lab, including chironomid larvae from streams and ponds. Colorado Division of Wildlife, Denver CO. 47 pages.
     Discussed as R. acropedes in a larval key.

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.
     Discussed as R. acropedes. Quote from page 611: "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). "

Smith,SD 1968 The Rhyacophila of the Salmon river drainage of Idaho with special reference to larvae. Annals of the Entomological Society of America 61 3, 655-674.
     Has a key to larvae that includes R. acropedes, which we now know as R. brunnea. However the author could not distinguish R. acropedes from the larvae of R. vao. R. vao has been reported from Summit County in Colorado, so it may be present in Gunnison County.

Smith,SD 1984 Larvae of Nearctic Rhyacophila, part I: acropedes group. Aquatic Insects 6:37-40.
     Synonymizes R. acropedes as Rhyacophila brunnea.

Smith,SD and Manuel,KL 1984 Reconsideration of the nearctic species of the Rhyacophila acropedes subgroup based on adults (Trichoptera: Rhyacophilidae). In Proceedings of the Fourth International Symposium on Trichoptera, JC Morse, ed Dr. W. Junk, The Hague.

Tate,CM and Heiny,JS 1995 The ordination of benthic invertebrate communities in the South Platte River Basin in relation to environmental factors. Freshwater Biology, 33(3) 439-454.
      They studied the South Platte river from the Southern Rocky Mountains through the Western High Plains ecoregion to the confluence with the North Platte River. R. brunnea was only found in the mountains.

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