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Order Ephemeroptera - Mayflies
Classification Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Class Insecta (Insects)
Order Ephemeroptera (Mayflies)
Other Common Names in angling or flyfishing terminology, an adult mayfly is called a spinner; the winged pre-adult is called a dun Explanation of Names EPHEMEROPTERA: from the Greek "ephemeros" (of or for a day; short-lived) + "pteron" (wing; feather) ...refering to the short time that adults are on the wing - normally only a day or two
["ephemeros" itself comes from "epi" (upon) + "hemera" (day)]
MAYFLY: adults normally appear in large numbers beginning in May Numbers more than 600 species in 21 families in North America ( nearctica.com)
about 2,200 species worldwide Size adult body length 2-32 mm (How to Know the Insects; Roger Bland) 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, and body dull and pubescent but otherwise similar to adult; 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 throughout North America 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 also attracted to light Season some adults emerge in late April (or even 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 all 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
adults do not feed; they have no functional mouthparts 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. Nymphs (or naiads) develop through several 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 imagos). Adult lifespan ranges from 1.5 hours to one or two weeks; most adults live only two or three days. Remarks Mayflies are the only group of insects that molt after they have wings.
Adults and nymphs are an important source of food for fish and other aquatic wildlife. Anglers often use mayflies as bait, or tie "flies" that are made to resemble adult mayflies (spinners) or pre-adults (dun). 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)
Internet References Tree of Life live adult images of two undetermined species by Alex Wild, plus classification and references
Insects of Cedar Creek overview of the order with links to families, giving habitat info but no images or biology (John Haarstad, U. of Minnesota)
links to info including species checklists, distribution, and classifcation, but no images, descriptions, or biology (Mayflies of North America, Purdue U., Indiana)
good overview of mayflies including description of life stages (with photos), life cycle, habitat, food, pest status, and links to a glossary of terms (Texas A&M University)
overview of biology, etc. with diagrams and links to other sites (North Carolina State U.)
links to live nymph images in several genera and families (Jason Neuswanger, New York)
Mayflies of North and South Carolina; PDF doc species checklist only (copy of article from Florida Entomologist, 1999)
angling terminology (first-nature.com, UK) |
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