Order Ephemeroptera - Mayflies

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)

The classification/nomenclature in the Guide generally follows (2)

Ephemeroptera Hyatt & Arms 1891

~650 spp. in ~110 genera of 23 families in our area(2); worldwide, ~3350 spp. in >440 genera of at least 42 families(3)(4)(5); 300 spp. in se. US(6), 204 in the Carolinas(7)(8), 71 in FL(9)

Overview of our fauna * taxa not yet in the guide(10)

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

1‒30 mm

worldwide and throughout NA; for ranges of nearctic spp., see(22)(2)(23)

some emerge in late April (earlier in the south) but the greatest numbers first appear in May

nymphs feed on 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 do not feed

Adult males usually gather in mid-air swarms 5‒15 m above the ground; females fly into the swarm, and mating occurs in flight. Females drop their eggs while flying low over the water, or by dipping the abdomen; some go underwater to lay eggs.

Mayflies are the only insects that molt in winged condition. There may be from several to dozens nymphal instars. Mature nymphs swim to water surface or crawl onto rocks or plants, then molt into winged subimagoes which then molt again into adults (imagoes). Adult lifespan ranges from 1.5 hours to two weeks, most adults live 48‒72 hrs.

Adults and nymphs are an important source of food for fish and other aquatic wildlife. Anglers often use mayflies as bait.