Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes


TaxonomyBrowse
Info
ImagesLinksBooksData

Order Ephemeroptera - Mayflies

Callibaetis pretiosus - female imago - Callibaetis pretiosus - female Mayfly - Isonychia Small Minnow Mayfly - male mayflies? - Ephoron leukon - male unidentified mayfly - Anthopotamus verticis Acentrella nadineae - female flatheaded mayfly - Stenacron interpunctatum - female aquatic0530 - Maccaffertium
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Ephemeroptera (Mayflies)
Other Common Names
in angling/flyfishing, an adult mayfly (imago) is called a spinner; the winged pre-adult (subimago) is called a dun; and many species have common names(1)
Synonyms and other taxonomic changes
The classification/nomenclature in the Guide generally follows Mayfly Central(2)
Explanation of Names
Greek ephemeros 'of/for a day; short-lived' + pteron 'wing' -- refers to the short-lived adults ["ephemeros" comes from epi 'upon' + hemera 'day']
MAYFLY: adults appear in large numbers in May
Numbers
611 spp. in 59 genera of 21 families in our area(3); worldwide, ~3350 spp. in >440 genera of at least 42 families(4)(5); 204 spp. in the Carolinas(6)(7)
Genera not yet in the Guide are listed in(8)
Overview of our fauna (* –taxa not yet in the guide)
Order Ephemeroptera
SUBORDER CARAPACEA
SUBORDER FURCATERGALIA
Infraorder LANCEOLATA

Infraorder *PALPOTARSA

Infraorder PANNOTA
Superfamily Caenoidea
Superfamily Ephemerelloidea

Infraorder SCAPPHODONTA
Superfamily Ephemeroidea
Superfamily *Euthyplocioidea
Superfamily Potamanthoidea
SUBORDER PISCIFORMA
Superfamily Heptagenioidea
Size
1-30 mm(3)
Identification
Adult (imago): body delicate or "flimsy", varying from almost transparent to white, yellow, orange, green, brown, or black; thorax and abdomen bare, often shiny; legs slender, solid color; front legs often held forward and sometimes upward in front of head when at rest; forewings large, triangular, with many cross veins; hindwings much smaller than forewings (hindwings absent in some species); both wings usually transparent but sometimes patterned, held vertically and together above thorax when at rest
Pre-adult (subimago): wings cloudy in appearance, body dull and pubescent, with appendages somewhat shorter -- but otherwise similar to imago; pre-adults molt a final time to become adults
Nymph: body elongate, flattened or cylindrical, usually greenish or brownish but color varies according to the type of food eaten; legs long; antennae short; abdomen with lateral plate-like gills and usually three long thin tail projections (cerci); some species have only two cerci
Range
worldwide and throughout NA; for ranges of nearctic spp., see(2)(9)
Habitat
most nymphs develop in streams and rivers that are well-oxygenated and relatively free of pollution; some species develop in lakes or ponds, usually in shallow water where the oxygen content is highest
adults may be found on vegetation near water, and are attracted to lights
Season
some emerge in late April (earlier in the south) but the greatest numbers first appear in May, and adults may be seen until September in the north; later, and perhaps around the year, in the far south
Food
nymphs feed on pieces of organic matter such as plant material or algae and debris that accumulates on rocks or other substrates in flowing water (predation recorded in some)
adults have no functional mouthparts and do not feed
Life Cycle
Mating and oviposition. Adult males gather in mid-air swarms, usually 5-15 metres above the ground; females fly into the swarm, and mating occurs in flight. Females deposit eggs while flying low over the water, or by dipping the abdomen into the water; some species submerge themselves and lay eggs underwater.
Development. Mayflies are hemimetabolous, that is, they undergo incomplete metamorphosis, a form of simple metamorphosis, and represent the only insect group whose members molt in winged condition. Nymphs (or naiads) develop through several (perhaps dozens) stages (instars) by molting. The number of molts varies depending on species, temperature, and water conditions. Mature nymphs swim to water surface or crawl onto rocks or plants, then molt into winged subadults (subimagos) which fly to nearby plants and molt again into adults (called imagoes). Adult lifespan ranges from 1.5 hours to two weeks; most adults live 48-72 hrs.
Remarks
Adults and nymphs are an important source of food for fish and other aquatic wildlife. Anglers often use mayflies as bait.
See Also
stonefly and caddisfly adults hold their wings together horizontally over the abdomen, and hugged closed to the body
stonefly nymphs have filamentous gills (not plate-like), and usually have two cerci (not three)
Print References
(10)
Internet References
Fact sheet (TAMU)