Ephemeroptera: Ephemerellidae of Gunnison County, Colorado
Drunella coloradensis (Dodds) 1923
Slate-Winged Olive, Small Western Green Drake
Updated 19 Apr 2017
Notice the "tubercles" on the front legs. That is a trait used to identify the genus Drunella. Look for the absence of gills on the first two abdominal segments. That indicates this larvae is in the mayfly family Ephemerellidae.
Also note the striped tails on this D. coloradensis larvae. Caught and released in the Upper East river, early August 2011.
On this website:
Allan,JD 1981 Determinants of diet of brook trout (Salvelinus fontinalis) in a mountain stream. Canadian Journal of Fisheries and Aquatic Sciences 38, 184-192. PDF
Allan,JD 1985 The production ecology of Ephemeroptera in a Rocky Mountain stream. Internationale Vereinigung für Theoretische und Angewandte Limnologie Verhandlungen 22, 3233-3237.
Allan,JD 1987 Macroinvertebrate drift in a Rocky Mountain stream. Hydrobiologia 144, 261-268.
Allen,RK and Edmunds,GF 1962 A revision of the genus Ephemerella (Ephemeroptera: Ephemerellidae). V. The subgenus Drunella in North America. Miscellaneous Publications of the Entomological Society of America 3, 147-179. PDF
Dahl, J and Peckarsky, BL 2003 Does living in streams with fish involve a cost of induced morphological defences? Canandian Journal of Zoology. 81(11): 1825-1828. PDF
Abstract: " Phenotypic plasticity may enable organisms to optimize their phenotypes in environments that are heterogeneous over time or space. For example, inducible defenses are favored for prey populations faced with variable predation risk. We studied the impact of brook trout (Salvelinus fontinalis) on the development of defensive morphological characters in larvae of the mayfly, Drunella coloradensis, both in natural streams and in a series of experiments carried out in streamside, circular, flow-through chambers. Drunella larvae in natural streams with trout had longer caudal filaments per unit body size and relatively heavier exoskeletons than Drunella in fishless streams. Female larvae that developed in fish streams were also significantly smaller and less fecund at metamorphosis than those living in fishless streams, suggesting a possible fitness cost associated with development of morphological defenses. However, timing of metamorphosis of Drunella larvae to the adult stage did not differ between fish and fishless streams.
Larvae originating from fish and fishless streams were reared and exposed to water with fish cues or fishless control water for three weeks (1998) or until they developed black wing pads, i.e., just before emergence (1999). In both experiments waterborne fish cues induced the development of relatively longer caudal filaments, but only in Drunella originating from sites without fish. Waterborne fish cues had no effect on Drunella growth rates, behavior, or size at emergence. Drunella originating from fish streams had significantly lower mortality when exposed to predation by trout than Drunella originating from fishless streams. Caudal filament length appears to enhance survival, as Drunella with intact caudal filaments had lower predation rates than Drunella with their tails artificially shortened. This study provides evidence of chemically induced morphological plasticity that could reduce predation rates of these mayflies in natural stream environments."
Dodds,GS 1923 Mayflies from Colorado: descriptions of certain species and notes on others. Transactions of American Entomological Society 69, 93-116.
Described as Ephemerella coloradensis.
Gilpin,BR and Brusven,MA 1970 Food habits and ecology of mayflies of the St. Maries River in Idaho. Melanderia 4:19-40. PDF
Discussed as Ephemerella (Drunella) coloradensis.
Hawkins,CP 1985 Food habits of species of ephemerellid mayflies (Ephemeroptera: Insecta) in streams of Oregon. American Midland Naturalist 113(2) 343-352. PDF
McCafferty,WP; Durfee,RS; Kondratieff,BC 1993 Colorado mayflies (Ephemeroptera): an annotated inventory. Southwestern Naturalist 38 3, 252-274. PDF
Quote from page 264-265: "Prior to 1987 this species was reported as Ephemerella coloradensis. ...This common western species ranges from Arizona to Alaska. "
Dahl,J and Peckarsky,BL 2002. Induced morphological defenses in the wild: predator effects on a mayfly, Drunella coloradensis. Ecology 83:1620-1634. Abstract
McCafferty,WP and Provonsha, AV The Mayflies of North America Species List (Version 8Feb2011)
Here is the geographic range and synonyms:
Drunella coloradensis (Dodds), 1923 [CAN:FN,NW;MEX:SW;USA:FN,NW,SW]
* Ephemerella coloradensis Dodds, 1923 (orig.)
* Ephemerella wilsoni Mayo, 1952 (syn.)
Pennuto,CM and deNoyelles Jr,F 1993 Behavioral responses of Drunella coloradensis (Ephemeroptera) nymphs to short-term pH reductions. Canadian Journal of Fisheries and Aquatic Sciences 50, 2692-2697.
Ward,JV and Berner,L 1980 Abundance and altitudinal distribution of Ephemeroptera in a Rocky Mountain stream. In Advances in Ephemeroptera biology (pp. 169-177). Springer US. PDF
Discussed as Ephemerella coloradensis.
Wellnitz,T 2014 Can current velocity mediate trophic cascades in a mountain stream?. Freshwater Biology, 59(11) 2245-2255. PDF
Winget,RN and Mangum,FA 1996 Environmental profile of Drunella coloradensis Dodds (Ephemeroptera: Ephemerellidae) in the Western United States. Journal of Freshwater Ecology 11 2, 225-232.
Abstract: "We describe several niche dimensions of Drunella coloradensis Dodds based upon physical and chemical parameters of over 900 stream stations in 11 western states. Nymphs were found at 199 stations and were collected at elevations from near sea level to over 9,000 ft and from streams with a wide range of water discharges. This mayfly showed significant avoidance of streams with <l% channel gradients and those where fine sediments dominated the substrate. Nymphs of D. coloradensis selected for waters with <100 mg/l alkalinity and <50 mg/l sulfate and streams with brush or evergreen trees dominating the riparian vegetation. Drunella coloradensis is intolerant of water quality degradation but moderately tolerant of other changes in the physical habitat. Drunella coloradensis shows divergence from related species through resource partitioning strategies related to water quality tolerances and physical habitat selection."
Drunella coloradensis larvae from the Upper East river in early August 2011.