Image: Mayfly

Mayfly

Mayfly, line drawing. Mayflies belong to the Order Ephemeroptera.

Creator:
Andrew Howells
Rights:
© Australian Museum

Notes

What do mayflies look like?

Size:
  • 4 mm - 35 mm in length with an average wingspan of 15 mm across.
Body:
  • Widest at wing attachment (wide shoulders), abdomen long and column-like.
  • Body appears soft and fragile.
Antennae:
  • Very short, bristle-like or thread-like.
Eyes:
  • Large, covering most of the head, and are very close together or actually touch.
Mouthparts:
  • Reduced in adult.
Wings:
  • One or two pairs but usually two.
  • Hindwings much smaller than forewings.
  • Both wings are membranous, clear and have numerous cross-veins forming many cells.
  • At rest wings are held upright above abdomen often pressed together.
Limbs:
  • Six slender legs.
Abdomen tip:
  • Usually three tails (two cerci, one middle filament) rarely two with middle tail reduced or absent; all tails longer than body, thread-like and similar in size.

Where are mayflies found?

  • Near water on vegetation, rocks or in the air.

What do mayflies do?

  • They group together in large numbers to form mating swarms. The swarms are often over a particular object such as a rock, tree, or bridge. This object can be indicative of a particular species.
  • When disturbed they fly away.
  • Many hold their front legs out in front when perched.
  • They are weak flapping fliers.
  • Adult mayflies do not feed.
  • Adults are short-lived, on average survive for 1-2 days, but can live for only minutes.
  • They are active night and day. Some are attracted to light.

What looks similar?

  • Stoneflies can be distinguished from Mayflies by their wings. Their wings are similar in size and folded around the body at rest. Stoneflies also never have more than two tails.
  • Caddisflies can be distinguished from Mayflies by their wings, antennae and a lack of tails. Their wings are hairy, similar in size and held tent-like at rest. While their antennae tend to be more than half their body length.
  • Alderflies and dobsonflies can be distinguished from Mayflies by a number of features. Their wings are similar in size and held tent-like at rest. They also have chewing mouthparts, long antennae and very short tails.
  • Flies can be distinguished from Mayflies by their wings and a lack of tails. The forewings of flies have few cells, while their hindwings are replaced by a club-like structure called halteres.
  • Male scale insects are occasionally confused as Mayflies. Wings of scale insects have few cells and their tails, if present, are never multi-segmented.

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Tags mayflies, insects, invertebrates, identification, Bugwise,