Ephemeroptera: Leptohyphidae of Gunnison County, Colorado
Tricorythodes explicatus (Eaton, 1892)
Trico, Trico Spinner, Tiny white winged black mayfly
Updated 26 Jan 2016
The mayfly Tricorythodes explicatus was first described by the Reverend Eaton in 1892. It is a widespread and variable species and after a long study of the Leptohyphidae family by Dr. Baumgardner, Tricorythus minutus (described in 1935) has recently been combined with T. explicatus. T. minutus was discussed in many scientific papers in the 20th century and is well known by fishermen.
Lake Fork, West Elk Creek, Cebolla Creek, Tomichi Creek (Argyle and Edmunds, 1962).
Hatch Chart for the Gunnison Gorge & Black Canyon from Cimarron Creek Guides in Montrose http://cimarroncreek.com/flyfishing/hatchchart.cfm
PAN Pesticides database:
Allen,RK and Murvosh,CM 1987 Mayflies (Ephemeroptera: Tricorythidae) of the Southwestern United States and Northern Mexico. Annals of the Entomological Society of America 80:35-40.
They descibe the nymph of T. explicatus. Their key splitting T. minutus and T. explicatus is moot since minutus is now a synonym of T. explicatus.
Argyle,DW and Edmunds,GF 1962 Mayflies (Ephemeroptera) of the Curecanti Reservoir Basins Gunnison River, Colorado. University of Utah Anthropological Papers 59 8, 178-189.
Discussed as Tricorythodes minutus. Quote from page 188: "Nymphs of this species were found predominantly in slow deep water or in the larger tributaries. They were found principally where a moderate current moves through vegetated areas or areas where organic detritus is deposited."
Baumgardner,DE 2009 Tricorythus minutus Traver, a new synonym of Tricorythodes explicatus Eaton (Ephemeroptera: Leptohyphidae). Proceedings of the Entomological Society of Washington 111(1):57-67. PDF
Dosdall, LM; Goodwin, LR; Casey, RJ; Noton, L 1997 The effect of ambient concentrations of chlorate on survival of freshwater aquatic invertebrates. Water Quality Research Journal of Canada. 32(4) 839-854.
Discussed as Tricorythodes minutus. Also mentioned in the PAN pesticides database link above and on the Ambient Water Quality Guidelines for Chlorate website from Government of British Columbia, Ministry of the Environment.
Eaton AE. 1892 Fam. Ephemeridae. Biologica Centrali-Americana 38:1-16.
Rev. Eaton describes the species Tricorythodes explicatus for the first time in this paper.
Edmunds Jr, GF. 1995 Habitat differences between northern and southern populations of mayflies of the western United States. Pages 171-176 in Corkum LD; Ciborowski JJH. Current Directions in Research on Ephemeroptera. Canadian Scholars' Press, Inc. Toronto.
Edmunds,GF and Musser,GG 1960 The mayfly fauna of Green River in the Flaming Gorge Reservoir Basin Wyoming and Utah. University of Utah Anthropological Papers 48:111-123.
Discussed as Tricorythodes minutus. Quote from page 119: " This common species is widespread. The nymphs are found on rocks and vegetation in Green River and warmer tributaries. Daily, particularly during the first two weeks in July, 1959, large flights of newly emerged adults swarmed along the edge of the river. The flight began about 7:00 o'clock A.M., reached a maximum density approximately an hour later, and gradually declined until noon, when only a few stragglers remained. The numbers in the swarm gradually decreased during the course of the expedition until, on the first of August, few emerging adults were observed. Large swarms have also been observed in September, so it is possible that there are two fairly distinct broods per year."
Kilgore,JL and Allen,RK 1973 Mayflies of the Southwest: new species, descriptions, and records (Ephemeroptera). Annals of the Entomological Society of America 66(2):321-332. PDF
Describes the larvae of T. minutus, among other things.
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
Lugo-Ortiz,CR and McCafferty,WP 1995 Annotated inventory of the mayflies (Ephemeroptera) of Arizona. Entomological News 106 3, 131-140.
Mangum,FA and Madrigal,JL 1999 Rotenone effects on aquatic macroinvertebrates of the Strawberry River, Utah: a five-year summary. Journal of Freshwater Ecology, 14(1), 125-135. PDF
Discussed as Tricorythodes minutus.
McCafferty,WP; Durfee,RS; Kondratieff,BC 1993 Colorado mayflies (Ephemeroptera): an annotated inventory. Southwestern Naturalist 38 3, 252-274. PDF
Discussed as Tricorythodes minutus. Quote from page 267: "This species is one of the most ubiquitous in North America, Nonetheless, it is susceptible to egg mortality at cold temperatures(Newell and Minshall, 1978) and is therefore not often found in cold springs and springbrooks in Colorado (Gray et al., 1983). In the material housed in PERC [Purdue Entomological Research Collection], collected from Routt Co., there are male adults typically small and colored as described for the species by Traver (1935). There are other male adults collected with them that are larger and fit Traver's (1935) description of T. fallax. Edmunds et al (1976) synonymized the two species and intimated that they may represent subspecies. Our Colorado collection suggests either individual variability or two cohabitating species, not subspecies. Any discovery of intergrades would tend to substantiate the synonymy." The authors also mention at the end of their discussion of faunistics that T. minutus is one of "those mayfly species that are truly widespread in North America""
McCafferty,WP and Provonsha, AV The Mayflies of North AmericaSpecies List (Version 8Feb2011)
Here is the geographic range and synonyms:
Tricorythodes explicatus (Eaton), 1892 [MEX:SW;CAN:NE,NW;USA:NE,NW,SW]
* Tricorythodes fallacina McDunnough, 1939 (syn.)
* Tricorythodes fallax Traver, 1935 (syn.)
* Tricorythodes minutus Traver, 1935 (syn.)
* Tricorythus explicatus Eaton, 1892 (orig.)
McCullough DA; Minshall GW; Cushing CE. 1979 Bioenergetics of a stream "collector" organism, Tricorythodes minutus (Insecta: Ephemeroptera). Limnology and Oceanography 24:45-58.
Newell,RL and Minshall,GW 1978 Effect of temperature on the hatching time of Tricorythodes minutus (Ephemeroptera: Tricorythidae). J. Kans. Ent. Soc. 51:504-506. PDF
Newell,RT and Minshall,GW 1978. Life history of a multivoltine mayfly, Tricorythodes minutus: an example of the effect of temperature on the life cycle. Annals of the Entomological Society of America 71:876-881. PDF
Includes the life history of T. minutus at two different sites. The spring-fed stream had a multivoltine (several generations/year) population, while the stream with a regular yearly temperature swing had a bivoltine population. They also have a description of the egg, populations, biomass, phenology, instars and more.
Ulmer, G 1920 Neue Ephemeropteren. Arch. Naturgesch. 85(abt. A 11):1-80.
Ulmer created the genus Tricorythodes for this species.
Wiersema,NA and McCafferty,WP 2000 Generic revision of the North and Central American Leptohyphidae (Ephemeroptera: Pannota). Transactions of American Entomological Society 126 3+4, 337-371. PDF
Places Tricorythodes in the subfamily Tricorythodinae. The other subfamily present in North America is Leptohyphinae. Has keys and illustrations to distinguish larvae and adult genera of the Leptohyphidae family.
Winget,RN 1993 Habitat partitioning among three species of Ephemerelloidea. Journal of Freshwater Ecology 8 3, 227-234. PDF
Winget,RN and Mangum,FA 1991 Environmental profile of Tricorythodes minutus Traver (Ephemeroptera: Tricorythidae) in the Western United States. Journal of Freshwater Ecology 63, 335-344. PDF
Abstract: "Based on data from 892 stations in 11 western states two geographic populations of Tricorythodes minutus Traver are described. The Great Basin population was found in streams that had sedimented substrate, sparse riparian vegetation, low channel gradients, and moderate to high concentrations of alkalinity and sulfates. The other population, found in California and Oregon, commonly occupied streams with moderate siltation, dense riparian vegetation, and low alkalinity and sulfate concentrations. The differences between the two populations could be the result of competitor or predator avoidance by one or both populations, or different limiting seasonal or irregular events may cause the separation. It is possible that the two populations represent subspecies or even two distinct species."
Zuellig,RE; Kondratieff,BC; Rhodes,HA 2002 Benthos recovery after an eposodic sediment release into a Colorado Rocky Mountain river. Western North American Naturalist 62 1, 59-72.