Ephemeroptera: Heptageniidae of Gunnison County, ColoradoEpeorus deceptivus
Flat headed mayfly(McDunnough) 1924
Updated 31 December 2025
TSN 100632
Good Links
On this website:
Introduction to Epeorus
Other Websites:
Photos, Map, Taxon Identifier Numbers - from the Global Biodiversity Information Facility Epeorus deceptivus at Gbif
Photos, Map, Museum specimens, DNA - Barcodinglife.org
References
Allan,JD and Feifarek,BP 1988 Prey preference in stoneflies: a comparative analysis of prey vulnerability. Oecologia, 76(4), pp.496-503.
Àlvarez,M and Peckarsky,BL 2005 How do grazers affect periphyton heterogeneity in streams? Oecologia 142: 576-587. PDF
Abstract: "The effects of grazing by stream invertebrates on algal biomass and spatial heterogeneity were tested experimentally in flow-through microcosms with natural substrates (rocks). One experiment tested the effects of fixed densities of three species of grazers (the caddisfly Allomyia sp. and two mayflies, Epeorus deceptivus and Baetis bicaudatus) on periphyton. Baetis was tested with and without chemical cues from fish predators, which reduced grazer foraging activity to levels similar to the less mobile mayfly (Epeorus). Mean algal biomass (chlorophyll a; chl a) was reduced in grazer treatments compared to ungrazed controls, but there were no differences among grazer treatments. Algal heterogeneity (Morisita index) increased with grazer mobility, with the highest heterogeneity occurring in the Baetis-no fish treatment (most mobile grazer) and the lowest in the caddisfly treatment (most sedentary grazer). A second experiment used a three factorial design, and tested whether initial resource distribution (homogeneous vs. heterogeneous), Baetis density (high vs. low) and fish odor (present vs. absent) affected grazer impact on algal resources. Abundances of Baetis and chl a on individual rocks were recorded to explore the mechanisms responsible for the observed distributions of algae. Initial resource heterogeneity was maintained despite being subjected to grazing. Mean chl a was highest in controls, as in experiment I, and effects of Baetis on algal biomass increased with grazer density. There were no fish effects on algal biomass and no effects of grazer density or fish on algal heterogeneity. At the scale of individual rocks Baetis was unselective when food was homogeneously distributed, but chose high-food rocks when it was heterogeneously distributed. Results of these mechanistic experiments showed that Baetis can track resources at the scale of single rocks; and at moderate densities mobile grazers could potentially maintain periphyton distributions observed in natural streams."
Alvarez,M and Peckarsky,BL 2013 The influence of moss on grazers in high-altitude streams: food, refuge or both? Freshwater Biology, 58(9) 1982-1994. PDF
Edmunds,GF and Allen,RK 1964 The Rocky Mountain species of Epeorus (Iron) Eaton (Ephemeroptera: Heptageniidae). Journal of the Kansas Entomological Society 37 (4) 275-288. Abstract PDF
Lehmkuhl,DM 1968 Observations on the life histories of four species of Epeorus in western Oregon (Ephemeroptera: Heptageniidae). Pan-Pacific Entomologist 44(2):129-137. PDF
McCafferty,WP; Durfee,RS; Kondratieff,BC 1993 Colorado mayflies (Ephemeroptera): an annotated inventory. Southwestern Naturalist 38 3, 252-274. PDF
Discussed as Iron deceptivus. There are museum specimens mentioned from the Crystal River, East River and Gunnison River. Quote from page 260: "This species is evidently restricted to the intermountain West (Edmunds and Allen, 1964) "
McCafferty,WP and Provonsha, AV The Mayflies of North AmericaSpecies List (Version 8Feb2011)
Here is the geographic range and synonyms:
Epeorus deceptivus (McDunnough), 1924 [CAN:FN,NW;USA:FN,NW,SW]
* Cinygma deceptiva McDunnough, 1924 (orig.)
* Iron deceptivus (McDunnough), 1924 (comb.)
McDunnough,J 1924 New Canadian Ephemeridae with notes, II. Canadian Entomologist 56, 90-98, 113-122, 128-133.
McIntosh,AR; Peckarsky,BL and Taylor,BW 2002 The influence of predatory fish on mayfly drift: extrapolating from experiments to nature. Freshwater Biology 47, 1497-1513. PDF
Peckarsky,BL 1990 Habitat selection by stream-dwelling predatory stoneflies. Canadian Journal of Fisheries and Aquatic Sciences 48, 1069-1076.
Peckarsky,BL 1991a A field test of resource depression by predatory stonefly larvae. Oikos 61 (1) 3-10.
Peckarsky,BL 1991b Is there a coevolutionary arms race between predators and prey? A case study with stoneflies and mayflies. Advances in Ecology 1, 167-180.
Peckarsky,BL 1996 Alternative predator avoidance syndromes of stream-dwelling mayfly larvae. Ecology, 77(6), pp.1888-1905. PDF
Abstract: "Experiments were conducted to compare the patterns, mechanisms, and costs of predator avoidance behavior among larvae of five species of mayflies that co-occur with the predatory stoneflies, Megarcys signata and Kogotus modestus in western Colorado streams. Mayfly drift dispersal behavior, use of high vs. low food (periphyton or detritus) patches, microhabitat use, positioning, and activity periodicity were observed in the presence and absence of predators in circular flow-through chambers using natural stream water. Also, distances from predators at which prey initiated escape responses were compared among prey and predator species. Costs of predator avoidance behavior were assessed by measuring short-term (24 h) feeding rates of mayflies in the presence or absence of predatory stoneflies whose mouthparts were immobilized (glued) to prevent feeding. The intensity and associated costs of predator avoidance behavior of mayfly species were consistent with their relative rates of predation by stoneflies. Megarcys consumes overwintering generation Baetis bicaudatus > Epeorus longimanus > Cinygmula = Ephemerella; Kogotus consumes summer generation Baetis > Epeorus deceptivus = Cinygmula; Megarcys eats more mayflies than Kogotus. While Megarcys induced drift by Baetis, Epeorus, and Cinygmula, this disruptive predator avoidance behavior only reduced food intake by Baetis and Epeorus. The morphologically defended mayfly species, Ephemerella, neither showed escape behavior from Megarcys, nor any cost of its antipredatory posturing behavior. Only Baetis responded by drifting from Kogotus. No mayfly species shifted microhabitats or spent less time on high-food patches in the presence of foraging stoneflies. However, predators enhanced the nocturnal periodicity of Baetis drift, which was negligible in the absence of stoneflies as long as food was abundant. Lack of food also caused some microhabitat and periodicity shifts and increased the magnitude of both day and night drift of Baetis. Thus, Baetis took more risks of predation by visual, drift-feeding fish not only in the presence of predatory stoneflies, but also when food was low or they were hungry. All other mayflies were generally nocturnal in their use of rock surfaces, as long as food was abundant. Finally, the distances at which different mayfly species initiated acute escape responses were also consistent with relative rates of predation. This study demonstrates alternative predator avoidance syndromes by mayfly species ranging from an initial investment in constitutive morphological defenses (e.g., Ephemerella) to induced, energetically costly predator avoidance behaviors (e.g., Baetis). Although the costs of Ephemerella's constitutive defense are unknown, experiments show that prey dispersal is the mechanism underlying fecundity costs of induced responses by Baetis to predators, rather than microhabitat shifts to less favorable resources or temporal changes in foraging activity. A conceptual model suggests that contrasting resource acquisition modes may account for the evolution and maintenance of alternative predator avoidance syndromes along a continuum from Baetis (high mobility) to heptageniids (intermediate mobility) to Ephemerella (low mobility). Prey dispersal (swimming) to avoid capture results in reduction of otherwise high fecundity by Baetis, which trades off morphological defense for enhanced ability to acquire resources. Thus, improved foraging efficiency is the selection pressure maintaining the highly mobile life style in Baetis, which increases resource acquisition and fecundity, offsetting the high mortality costs associated with this behavior."
Peckarsky,BL; Cowan,CA 1995 Microhabitat and activity periodicity of predatory stoneflies and their mayfly prey in a western Colorado stream. Oikos 74 3, 513-521.
Peckarsky,BL and Penton,MA 1989 Mechanisms of prey selection by stream-dwelling stonefly nymphs. Ecology 70(5) 1203-1218. Abstract
Radford,DS and Hartland-Rowe,R 1971 The life cycles of some stream insects (Ephemeroptera, Plecoptera) in Alberta. The Canadian Entomologist, 103(4) 609-617.
Names have changed since 1971:
| 1971 Name |
2020 Name |
| Nemoura besametsa |
Prostoia besametsa |
| Epeorus deceptivus |
Epeorus deceptivus |
| Epeorus longimanus |
Epeorus longimanus |
| Ephemerella coloradensis |
Drunella coloradensis |
| Arcynopteryx aurea |
Perlinodes aurea |
| Nemoura cinctipes |
Zapada cinctipes |
| Nemoura columbiana |
Zapada columbiana |
| Nemoura oregonensis |
Zapada oregonensis |
| Cinygmula ramaleyi |
Cinygmula ramaleyi |
| Ephemerella doddsi |
Drunella doddsi |
| Rhithrogena doddsi |
Rhithrogena hageni |
Abstract: " The life histories of Nemoura besametsa, Epeorus deceptivus, Epeorus longimanus, and Ephemerella coloradensis are described as "fast seasonal" types and Arcynopteryx aurea, Nemoura cinctipes, Nemoura columbiana, Nemoura oregonensis, Cinygmula ramaleyi, Ephemerella doddsi, and Rhithrogena doddsi as "slow seasonal" types according to Hynes´ (1961) classification. All of the species are univoltine with the exception of N. cinctipes which may be bivoltine. There seems to be a correlation between life cycles and food availability. A means of ecological separation in the four Nemoura species is elucidated. Stream temperature was found to influence growth rates."
Zuellig,RE; Heinold,BD; Kondratieff,BC and Ruiter,DE 2012 Diversity and Distribution of Mayflies (Ephemeroptera), Stoneflies (Plecoptera), and Caddisflies (Trichoptera) of the South Platte River Basin, Colorado, Nebraska, and Wyoming, 1873-2010. U.S. Geological Survey Data Series 606, 257 p. PDF - caution 46MB
Quote from page 31: "This western intermountain Epeorus species usually occurs at higher elevations than other Epeorus species (Edmunds and Allen, 1964)." The elevation range is 8,200-10,850 feet and the adults emerge from August-September.
Brown,WS 2004 Mayflies (Ephemeroptera) of Gunnison County, Colorado, USA
www.gunnisoninsects.org
"We never tire of each other, the mountain and I." --Lao Tzu
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