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Ephemeroptera: Ameletidae of Gunnison County, Colorado

Ameletus similior

McDunnough, 1928
Updated 22 Mar 2023
TSN 101012


Sometimes misspelled Ameletus similor.

Good Links

On this website:
Ameletus Introduction

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

North American distribution map - flyfishingentomology.com


Benton,MJ 1989 Energy budgets and reproductive ecologies of mayflies occupying disparate thermal environments. Canadian Journal of Zoology, 67(11), pp.2782-2791.
     Abstract: " Energy budgets were calculated for two populations of Ameletus occupying thermally disparate habitats. Growth, consumption, respiration, fecundity, and energy content of larvae and eggs were determined experimentally. Respiration rates increased and decreased with temperature throughout the life cycles of both species, although thermal effects became less pronounced with increased body size. Ameletus similior exhibited more uniform and consistently higher respiration values than Ameletus celer. Respiration costs were not constant over the life cycle of either species as has been reported for some other mayflies. Growth was influenced by both temperature (which affected instar duration) and body size (which affected growth ratio). Growth corresponded positively to temperature in both species, but was more uniform in A. celer. Net growth efficiency and assimilation were highest during cold periods in A. celer, but highest during warmer periods in A. similior. Consumption estimates were high even after adjustments for projected nonfeeding time, but unless food availability or handling time is limiting, the feeding rate of Ameletus relative to body mass may be higher than rates reported for other aquatic insect larvae. Several sources of error in consumption estimates existed, however. Assimilation efficiencies were low, but comparable to those for other herbivorous aquatic insects. Reproductive effort was higher in A. celer, but net reproductive effort was lower. The higher net reproductive effort by A. similior did not result in increased fecundity as expected, but in higher egg energy content. This and other factors suggest that A. similior displays more "K-selected" traits than A. celer, and indicates that greater fitness may not necessarily be synonymous with higher fecundity in all mayflies in all habitats. "

Benton,MJ and Pritchard,G 1990 Mayfly locomotory responses to endoparasitic infection and predator presence: the effects on predator encounter rate. Freshwater Biology 23(2) 363-371 Abstract

McCafferty,WP; Durfee,RS and Kondratieff,BC 1993 Colorado mayflies (Ephemeroptera): an annotated inventory. Southwestern Naturalist 38 3, 252-274. PDF
     The Purdue University Entomological Collection (PERC) has specimens from the Gunnison River. Quote from page 254: "This species was previously known from Alberta, and the first author has seen specimens from Idaho. There is a possibility that A. celer and A. similior represent varients of the same species."

McDunnough,J 1928 The Ephemeroptera of Jasper Park, Alta. Canadian Entomologist 60, 8-10.

Newell,RL and Hossack,BR 2009 Large, wetland-associated mayflies (Ephemeroptera) of Glacier National Park, Montana. Western North American Naturalist, 69(3) 335-342. Abstract and PDF

Pritchard,G and Zloty,J 1994 Life histories of two Ameletus mayflies (Ephemeroptera) in two mountain streams: the influence of temperature, body size, and parasitism. Journal of the North American Benthological Society 13 4, 557-568. PDF
     Discusses Ameletus similior in Alberta, Canada. Both A similior and A. celer were parasitized by Mermithid nematodes. A. similior spends the winter diapausing as an egg. They are univoltine (one generation per year).

Zloty,J 1996 A revision of nearctic Ameletus mayflies based on adult males, with descriptions of seven new species (Ephemeroptera: Ameletidae). Canadian Entomologist 128, 293-346. PDF

Zloty,JS 1998 Systematics of nearctic Ameletus mayflies (Ephemeroptera: Ameletidae). PhD Thesis University of Calgary.
     Abstract: "A systematic revision of North American species of the genus Ameletus, excluding parthenogenetic species, is presented. Seven new species are described (A. andersoni, A. bellulus, A. doddsianus, A. edmundsi, A. majusculus, A. pritchardi, and A. tolae), separate keys are given to western and eastern species, annotated accounts of all 30 presently recognized bisexual species are provided, taxonomic characters are illustrated, and distribution data are presented for all species. The following nomenclatural changes are proposed: Ameletus aequivocus is considered a junior synonym of A. sparsatus; A. alticolus and A. celeroides junior synonyms of A. celer; A. connectina and A. connectus junior synonyms of A. velox; A. facilis a junior synonym of A. vancouverensis; A. monta a junior synonym of A. similior; A. querulus a junior synonym of A. shepherdi; A. tuberculatus is provisionally considered to be a junior synonym of A. celer..."

Zloty,J and Pritchard,G 1997 Larvae and adults of Ameletus mayflies (Ephemeroptera: Ameletidae) from Alberta. Canadian entomologist, 129(2) 251-290. PDF
     Description of larvae and adults.

Brown,WS 2004 Mayflies (Ephemeroptera) of Gunnison County, Colorado, USA