Mayfly

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{{Taxobox | color = pink | name = Mayflies | image = Haft.jpg | image_width = 200px | regnum = Animalia | phylum = Arthropoda | classis = Insecta | ordo = Ephemeroptera | ordo_authority = Hyatt & Arms, 1891 | subdivision_ranks = Suborders | subdivision = Suborder Schistonota
Superfamily Baetoidea
   Siphlonuridae
   Baetidae
   Oniscigastridae
   Ameletopsidae
   Ametropodidae
Superfamily Heptagenioidea
   Coloburiscidae
   Oligoneuriidae
   Isonychiidae
   Heptageniidae
Superfamily Leptophlebioidea
   Leptophlebiidae
Superfamily Ephemeroidea
   Behningiidae
   Potamanthidae
   Euthyplociidae
   Polymitarcydae
   Ephemeridae
   Palingeniidae
Suborder Pannota
Superfamily Ephemerelloidea
   Ephemerellidae
   Leptohyphidae
   Tricorythidae
Superfamily Caenoidea
   Neoephemeridae
   Baetiscidae
   Caenidae
   Prosopistomatidae
}}

The mayflies belong to the order Ephemeroptera (Ephemeroptera: Greek Ephemeros - short-lived, pteron - wing, referring to the short life span of adults). They have been placed into an ancient group of insects termed the Paleoptera (the dragonflies also belong to this group.) They are an aquatic insects where the larval stage occurs in fresh water. The adults are short-lived, maybe as little as a few hours to a day or two, depending on the species. Worldwide about 2,500 species are known. In North America, there are about 630 species. Some common names for these insects include dayfly, shadfly, fishfly, and Canadian soldier.

Image:Ephemeroptera01.jpg The larvae (sometimes the term nymph is used in the older literature) live primarily in streams under rocks or in the sediment. Very few species live in lakes, but those that do can occur in huge numbers. For example, the emergence of one species of Hexagenia was recorded on doppler radar along the shores of Lake Erie. Most species graze on algae. There are very few predaceous species. In the USA the predaceous species tend to live in sand bottomed streams such as those found in Nebraska and Iowa (certain streams in Indiana and Illinois have also been known to have the predaceous forms.) The larval stage may last from several months to as long as several years, with a number of molts along the way. Mayfly larvae are distinctive in having seven pairs of abdominal gills. 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 molt 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 favorite food of many fish, and many fishing flies are modeled to resemble them.

The primary function of the adult is reproduction; the mouthparts are vestigial, and the digestive system is filled with air. The wings are membraneous (similar to a house fly's wings but with many more veins). The forewings are much larger than the hind wings. The males' eyes are usually large, and the front legs long, used to grasp females and often held in front when resting. In some species, all legs aside from the males' front legs are useless. The majorty of the life of the adult is spent in mating swarms.

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; this kind of mayfly is called the tiszavirág or "Tisza flower".

Both immature and adult mayflies are an important part of the food web, particularly for carnivorous fish such as trout in cold water streams or bass and catfish in warm water streams.

Mayflies are also an industrial nuisance, as the large population of dead adults can clog the intakes of air and water supply systems. A good example of this is found in the nuclear industry when plants located near fresh water can have their cooling water intakes clogged by the corpses.

In literature mayflies can sometimes illustrate something hard to find and/or obtain.

There are four North American species believed to be extinct. Pentagenia robusta was originally collected from the Ohio River near Cincinati, but this species has not been seen since its original collection in the 1800's. Similarly, Ephemera compar was reported from the "foothills of Colorado." Despite intensive surveys of the Colorado mayflies, this species has not been collected in the past half century. The Large blue lake mayfly is listed as vulnerable. The status of most species of mayflies is unknown as numerous species are only known from the original collection data.

In certain regions of New Guinea and Africa, mayflies are eaten when they emerge en masse on a certain day.

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External links

Mayfly Central hosted by Purdue University

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Sources from the Scientific Literature

Berner, L. M. L. Pescador. 1988. The mayflies of Florida. Revised Edition. University of Florida Presses, Tallahassee.

Burks, B. D. 1953. The mayflies, or Ephemeroptera, of Illinois. Bulletin of the Illinois Natural History Museum 26: 1-216.

Edmunds, G.F., Jr. S.L. Jensen, and L. Berner. 1976. The mayflies of North and Central America. University of Minnesota Press, Minneapolis (out of print).

McCafferty, W. P. 1994. Distributional and classificatory supplement to the burrowing mayflies (Ephemeroptera: Ephemeroidea) of the United States. Entomological News 105: 1-13.

McCafferty, W. P. 1991. Comparison of old and new world Acanthametropus (Ephemeroptera: Acanthametretopodidae) and other psammophilous mayflies Entomological News 102: 205-214.

McCafferty, W. P. 1996. The Ephemeroptera species of North America and index to their complete nomenclature. Transactions of the American Entomological Society 122: 1-54.

McCafferty, W. P. 2001. The gentle quest: 200 years in search of North American mayflies. pp. 21-35 in Trends in Research in Ephemeroptera and Plecoptera. E. Dominguez, ed. Kluwer Academic/Plenum Publishers.

McCafferty, W. P., R.S. Durfee, and B.C. Kondratieff. 1997. Colorado mayflies: an annotated inventory. Southwest Naturalist 38: 252-274.

McCafferty, W. P., T. Hubbard, T. H. Klubertanz, R. P. Randolph, and M. Birmingham. 2003. Mayflies (Ephemeroptera) of the Great Plains. II: Iowa. Transactions of the American Entomological Society 129: 77-105.

Randolph, R.P. and W. P. McCafferty. 1998. Diversity and distribution of the mayflies (Ephemeroptera) from Illinois, Indiana, Kentucky, Michigan, Ohio, and Wisconsin. Ohio Biological Survey Bulletin NS13(1): vii + 188pp.

Randolph, R. P. and W. P. McCafferty. 2001. New species and records of the mayflies (Insecta) from Mexico. <i>Dugesiana 8: 15-21.

Needham, J.G., J. R. Traver, and Y.C. Hsu. The biology of mayflies. Comstock Publishing CO., Ithaca, NY. Out of print.

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