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Order Ephemeroptera

(Mayfly)

Soil & Water Conservation Society of Metro Halifax (SWCSMH)

Updated: October 09, 2013

Linnean system of hierarchical classification

(Williams & Feltmate, 1992)

Superphylum Arthropoda

(jointed-legged metazoan animals [Gr, arthron = joint; pous = foot])

Phylum Entoma

Subphylum Uniramia

(L, unus = one; ramus = branch, referring to the unbranched nature of the appendages)

Superclass Hexapoda

(Gr, hex = six, pous = foot)

Class Insecta

(L, insectum meaning cut into sections)

Subclass Ptilota

Infraclass Palaeopterygota

Introduction

These have a fossil record that is relevant to the issue of the evolutionary origin of wings in the Insecta. Carboniferous mayflies include gigantic species with wing spans of atleast 45 cm. Modern Ephemeroptera number about 2000 species in 19 families, most of them associated with running water. The adults are less diverse in form than the nymphs.

The mayflies belong to the infraclass Paleoptera; their primitive wings cannot be folded over their backs. They are among the most primitive aquatic insects and probably arose in the Carboniferous period, 280-350 million years ago. The taxonomy of the immature stages is poorly known because the nymphs of many species have not yet been associated with adult forms.

Life History

Mayflies are hemimetabolous insects well known for their short-lived (ephemeral) adult phase, which usually lasts from two hours to three days. Mayflies are unique insects in that they have two adult stages. Both are winged, short-lived (1-2 hours to a maximum of 14 days) and do not feed. The subimago (dun) is a stage of sexual maturation in which the wings are semi-opaque and covered in minute hairs (microtrichia) with longer setae on the margins. Beneath the subimaginal cuticle the adult eyes, legs and genitalia are clearly visible. The mature adult (imago) that emerges when the subimago moults has much longer legs and cerci, and wings that are clear and bare.

In contrast to the imagos, mayfly nymphs exhibit considerable diversity in appearance although many stream species are dorso-ventrally flattened. Mayfly nymphs go through a large number of moults as they grow, with most species having 15-25 instars. Estimates for some species reach as high as 50 and variations occur within single species.

Distribution and Habitat

The order Ephemeroptera has a cosmopolitan distribution but is absent from the Arctic and antartic. They are absent from oceanic islands, but New Zealand has a good fauna. Chemical tolerance is less well known for mayflies than for some other groups. Life forms of mayfly larvae are diverse, but they fall into four broad categories: burrowing, flattened, swimming, and creeping.

They reach peak abundance in cool, clean headwater streams, where they are an important source of food for fish. Some species can regulate respiratory movements of gills in response to changing oxygen concentrations. Mayfly nymphs are characteristic of shallow streams and littoral areas of lakes, and are distributed widely. However, many species are restricted to specific substrata of macrophytes, sediments of waveswept or moving stream areas, or sediments of specific sized particles.

Typical nymphal habitats (Williams & Feltmate, 1992)

Family	Primary distribution	Habitat
Suborder Schistonota
Superfamily Baetoidea/Heptagenioidea
Siphlonuridae	largely Holarctic	chiefly running water
Colorburiscidae	S. Hemisphere	stony upland streams
Oniscigastridae	S. Hemisphere	lotic & lentic
Ameletopsidae	S. Hemisphere	stony upland streams
Ametropodidae	Holarctic	large rivers
Baetidae	widespread	chiefly running water
Metretopodidae	Holarctic	fast-flowing water
Oligoneuriidae	esp. Afrotr/Neotrop/ some Holarc. & Orient.	running water
Heptageniidae	largely Holarctic	lotic & lentic-erosional
Superfamily Leptophlebioidea
Leptophlebiidae	esp. S. Hemisphere/ some Holarc. & Orient	esp. fast-flowing waters
Superfamily Ephemeroidea
Behningiidae	Holarctic	burrowers in river sand
Potamanthidae	largely Asian/some N.A.	lotic-depositional
Euthyplociidae	esp. Neotrop./Afrotr.	sand burrowers
Polymitarcyidae	esp. Neotrop./Afrotr./ some in Holarctic	burrowers in stream & river beds
Ephemeridae	Oriental/Afrotr/Holarc.	lotic & lentic burrowers
Palingeniidae	Afrotr/Orient/Palaearc.	burrowers in river beds
Suborder Pannota
Superfamily Ephemerelloidea
Ephemerellidae	widespread	chiefly running water
Tricorythidae	esp. Afrotr./Neotrop.	lotic-deposit/lentic littoral
Leptohyphidae	esp. Neotrop./some N.A.	lotic
Superfamily Caenoidea
Neoephemeridae	Holarctic & Oriental	lotic-depositional
Caenidae	widespread	lotic-deposit/lentic-litt.
Superfamily Prosopistomatoidea
Baetiscidae	esp. eastern N. Amer.	lotic-depositional
Prosopistomatidae	Afrotr./some Oriental	lotic-depositional

Feeding

They are primarily grazers and collector-gatherers. Some species are predaceous, and others have interesting adaptations for filter feeding (Oligoneuriidae). The diet of most mayflies is composed of algae and detritus.

Indicator value

These insects of inland waters are aquatic only in their juvenile stages. In general, mayfly nymphs tend to live mostly in unpolluted lakes, ponds, streams and rivers where, with densities of up to 10,000/sq.metre, they contribute substantially to secondary production. However, very small amounts of organic pollution can sometimes, initially, increase the numbers and production of certain species while others are exterminated. Species of Baetis (Family Baetidae) seem the most tolerant to pollution and these and others are often used as indicators of water quality.

Burrowing nymphs such as Hexagenia bilineata (Family Ephemeridae) do particularly well in silted impoundments and the problems associated with their mass emergence from the Mississippi River are notorious- e.g. accumulation of adult bodies on road bridges create slippery surfaces for motorists.

Physiological and ecological tolerances and requirements of common mayfly nymphs

(Mackie, 2001)

Species General habitat Feeding pH Oxygen % Trophic
level
Baetis vagans gravel, streams scraper ≥7 100 Oligo
Epeorus vitreus gravel, streams shredder >7 100 Oligo
Ephemera simulans sand, gravel, lakes, streams predator, gatherer, shredder ≥7 50-100 Meso-Oligo
Ephemerella subvaria gravel, streams scraper approx. 7 100 Oligo
Ephemerella cornuta gravel, streams scraper approx. 7 100 Oligo
Heptagenia flavescens wood, rock, streams shredder, gatherer ? 50-100 Meso-Eutro
Hexagenia limbata mud, lakes predator >7 ≅100 Meso-Oligo
Hexagenia recurvata mud, cold streams predator ≥7 100 Oligo
Isonychia bicolor swimmer, streams filter feeder ≥7 100 Oligo
Paraleptophlebia debilis gravel, rocks, streams gatherer, shredder >7 100 Dyst-Oligo
Rhithrogena undulata gravel, rocks, streams gatherer ≥7 100 Oligo
Stenacron interpunctatum rocks, lakes, streams, ponds gatherer, scraper <7 - >7 25-100 all levels
Stenonema tripunctatum rocks, streams gatherer, scraper ≥7 - >7 50-100 all levels
Stenonema femoratum rocks, streams gatherer, scraper >7 100 Oligo
Tricorythodes minutus indifferent, streams only gatherer >7 25-100 Meso, Dyst

Species	General habitat	Feeding	pH	Oxygen %	Trophic level
Baetis vagans	gravel, streams	scraper	≥7	100	Oligo
Epeorus vitreus	gravel, streams	shredder	>7	100	Oligo
Ephemera simulans	sand, gravel, lakes, streams	predator, gatherer, shredder	≥7	50-100	Meso-Oligo
Ephemerella subvaria	gravel, streams	scraper	approx. 7	100	Oligo
Ephemerella cornuta	gravel, streams	scraper	approx. 7	100	Oligo
Heptagenia flavescens	wood, rock, streams	shredder, gatherer	?	50-100	Meso-Eutro
Hexagenia limbata	mud, lakes	predator	>7	≅100	Meso-Oligo
Hexagenia recurvata	mud, cold streams	predator	≥7	100	Oligo
Isonychia bicolor	swimmer, streams	filter feeder	≥7	100	Oligo
Paraleptophlebia debilis	gravel, rocks, streams	gatherer, shredder	>7	100	Dyst-Oligo
Rhithrogena undulata	gravel, rocks, streams	gatherer	≥7	100	Oligo
Stenacron interpunctatum	rocks, lakes, streams, ponds	gatherer, scraper	<7 - >7	25-100	all levels
Stenonema tripunctatum	rocks, streams	gatherer, scraper	≥7 - >7	50-100	all levels
Stenonema femoratum	rocks, streams	gatherer, scraper	>7	100	Oligo
Tricorythodes minutus	indifferent, streams only	gatherer	>7	25-100	Meso, Dyst

References and web URLs:

Hutchinson, G.E. 1993. A Treatise on Limnology. Vol. IV, The Zoobenthos. Ed. Y.H. Edmondson. John Wiley & Sons, Inc. Xx, 944pp.

Mackie, G.L. 2001. Applied Aquatic Ecosystem Concepts. Kendall/Hunt Publishing Company. xxv, 744 pp. ISBN 0-7872-7490-9

Narf, R. 1997. Midges, bugs, whirligigs and others: The distribution of insects in Lake "U-Name-It". Lakeline. N. Am. Lake Manage. Soc. 16-17, 57-62.

Peckarsky, B.L., P.R. Fraissinet, M.A. Penton, and D.J. Conklin, Jr. 1990. Freshwater Macroinvertebrates of Northeastern North America. Cornell Univ. Press. xii, 442pp.

Wetzel, R.G. 1983. Limnology. 2nd ed. Saunders College Publishing. Xii, 767pp, R81, I10.

Williams, D.D., and Feltmate, B.W. 1992. Aquatic Insects. CAB International. ISBN: 0-85198-782-6. xiii, 358p.

Mandaville, S.M. 1999. Bioassessment of Freshwaters Using Benthic Macroinvertebrates-A Primer. First Ed. Project E-1, Soil & Water Conservation Society of Metro Halifax. viii, Chapters I-XXVII, Appendices A-D. 244p.

For the entire Report, download all the files in the subdirectory, Primer1
Chapter III: Order Ephemeroptera (mayflies)

Tree of Life

New York Department State of Environmental Conservation

Mayfly Central- Purdue Univ.

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