Any insect of the order Ephemeroptera, found around streams and ponds. The approximately 2,000 species are up to 1.6 in. (4 cm) long, have triangular membranous forewings, smaller round hind wings, and two or three long, threadlike tails. Wings are held vertically when at rest. Chewing mouthparts in the aquatic larvae are vestigial in the adult, which lives just long enough to mate and reproduce. Males “dance” in large swarms to attract females. The adult's entire life span is usually only a few hours (though at least one species lives as long as two days), and poets have used the mayfly as a symbol of life's ephemeral nature.
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The mayfly belongs to group 1 taxa, or pollution–sensitive animals. This means if mayflies are in or around the water, the water should be of a good quality.
Eggs are laid on the surface of lakes or streams, and sink to the bottom. Naiads moult 20 to 50 times over a period of a few months up to year, depending on the species. The naiads live primarily in streams under rocks, decaying vegetation, or in the sediment. Few species live in lakes, but they are among the most prolific. For example, the emergence of one species of Hexagenia was recorded on doppler radar along the shores of Lake Erie.
Most species feed on algae or diatoms, but there are a few predatory species. The naiad stage may last from several months to as long as several years, with a number of moults along the way. Mayfly naiads are distinctive in that most have seven pairs of gills on the dorsum of the abdomen. In addition, most possess three long cerci or tails at the end of their bodies. (Some species, notably in the genus Epeorus, have only two tails.) In the last aquatic stage, dark wingpads are visible. Developmentally, these insects are considered hemimetabolous insects. A more casual and familiar term is incomplete metamorphosis. Mayflies are unique among the winged insects in that they moult one more time after acquiring functional wings (this is also known as the alate stage); this second-to-last winged instar is usually very short, often a matter of hours, and is known as a subimago or to fly fishermen as a dun. This stage is a favourite food of many fish, and many fishing flies are modelled to resemble them.
It often happens that all the mayflies in a population mature at once (the hatch), and for a day or two in the spring or fall, mayflies will be everywhere, dancing around each other in large groups, or resting on every available surface. This happens in mid-June on the Tisza River in Serbia and Hungary; this kind of mayfly is called the tiszavirág (in Hungarian) or "tiski cvet" in Serbian which is translated as "Tisza flower". This natural phenomenon is called Tisza blooming. In certain regions of New Guinea and Africa, mayflies are eaten when they emerge en masse on a certain day.
Because of its short lifespan, the mayfly is also called one–day fly in some languages — French éphémère, German Eintagsfliege, Dutch eendagsvlieg, Slovenian enodnevnica, Swedish dagslända, Danish and Norwegian døgnflue, Polish jętka jednodniówka.
It's prime time for slippery, smelly mayflies; "They'll go down your shirt. They'll get in your hair. They'll go in your ears. It's that bad.".(NEWS)
Jul 22, 2004; Byline: Jill Burcum; Staff Writer Wild horses couldn't keep diehard fisherman Dirk Wassink from trolling the Mississippi River...