Mayfly

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Mayfly
Temporal range: Late Carboniferous (Pennsylvanian) – Recent
Rhithrogena germanica
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Subclass: Pterygota
Infraclass: Palaeoptera
Order: Ephemeroptera
Ephemera danica, Belgium
by Luc Viatour.
Mississippi River mayfly hatch so heavy it shows up on weather radar

Mayflies are insects which belong to the Order Ephemeroptera (from the Greek ephemeros = ephemeral, or short-lived; pteron = wing). The name refers to the most distinctive features of the adults. They are in an ancient group of insects, the Palaeoptera, ('Ancient wings') with dragonflies and damselflies.[a]

Egg stage[change | change source]

At mating the female lays her eggs in the water.[2] They settle to the bottom where they stick to rocks, vegetation or the bottom of the stream. They range in size by the particular species of Mayfly. Depending on temperature, the eggs incubate from less than one to three months.[2] Two weeks is about the average time. During this embryonic stage the mouth, legs, tail and organs all develop.[2]

Larva (or nymph) stage[change | change source]

Mayfly are insects whose aquatic larvae (called naiads or nymphs) live from several months up to a year, in freshwater.[2] The adults are extremely short-lived, from 30 minutes to one day, depending on the species. The function of the adult imago is reproduction and dispersal; they do not eat. The naiads go through 20 or 30 moults as they develop.[b] The development is 'incomplete metamorphosis' (or incomplete life cycle).

Adult stage[change | change source]

Mayflies are unique in that they moult one more time after getting functional wings (this is also known as the alate stage). This second-to-last winged stage is usually very short, usually less than three days.[3] The stage is a favourite food of many fish, and many 'fishing flies' are modeled on them.

The hatch[change | change source]

It often happens that all the mayflies in a population mature at once (called the hatch). For a day or two in the Spring or Autumn (Fall), mayflies will be everywhere, dancing around each other in large groups, or resting on every available surface.[4] The adults have various special features. Their rear wings are small or almost vestigial; the males have two long front legs for holding females, the rest have no function. Mating is usually in mid-air. The mayfly are quite a successful group. About 2,500 species are known worldwide, including about 630 species in North America.[5] The hatch at La Crosse, Wisconsin has been a news event for several years. The hatch is so large it appears on weather radar.[6] The emerging Mayflies land on everything and cover some areas like snow.[6]

Notes[change | change source]

  1. They may not be a natural monophyletic group.[1]
  2. Moult or ecdysis: shedding the cuticle (exoskeleton) of arthropods.

References[change | change source]

  1. Trueman, John W.H. 2008. Tree of Life Web Project – [1]. Version of 2008-Mar-20. Retrieved 2008-Dec-15.
  2. 2.0 2.1 2.2 2.3 Al Caucci; Bob Nastasi; Art Flick; et al., Hatches II: A Complete Guide to the Hatches of North American Trout Streams (Guilford, CT: Lyon's Press, 2004), p. 29
  3. Hugh F. Clifford, Aquatic Invertebrates of Alberta: An Illustrated Guide (Edmonton: University of Alberta Press, 1991), p. 191
  4. Lewis Berner; Manuel L. Pescador, The Mayflies of Florida (Gainesville: University Presses of Florida, 1988), p. 132
  5. Hoell H.V; Doyen J.T. & Purcell A.H. 1998. Introduction to insect biology and diversity. 2nd ed, Oxford University Press. p. 320. ISBN 0-19-510033-6.
  6. 6.0 6.1 "Mayfly hatch shows up on weather radar near La Crosse, Wis.". USATODAY.com. 7/7/2006. http://usatoday30.usatoday.com/weather/news/2006-07-07-mayfly-radar_x.htm. Retrieved 22 May 2014.