Animal of the Week May 8, 2006 -- Mayflies

"What a difference a day makes, 24 little hours..." Dinah Washington new what she was singing about, she was singing about Ephemeroptera (mayflies). I know I normally do a single species and not a whole order of animals, but really, as if I am going to want to cover mayflies in AOTW again...*

There are over 2000 species of mayflies, and this group is one of the most ancient of insect orders. All mayflies are characterised by a short adult life lasting, in most cases, no more than a day; although they have a larval stage or nymph that lasts from a few weeks to several years. The nymphs live in fresh water rivers or streams, feedings and preparing for a frenetic adulthood. Commonly huge swarms explode from rivers over a very short period, at this time fish, birds, and, in some parts of the world, humans gorge themselves on the glut of crunchy goodness. In temperate Europe and North America most of the hatches happen between April and July. So any day now folks. Nuclear reactor workers do well to prepare for the hatchings as the masses of dead mayflies have been known to block the intake of water for cooling.

People thinking of eating mayflies should remain mindful of the story of Deichtine. In Irish myth, the god Lugh, in the form of a mayfly, landed in Deichtine's drink and after being swallowed made her pregnant with Setanta (who later adopted the name Cuchulainn and became one of the great heroes of Ulster). Not sure if that can really happen, but it's probably best to cover your mouth if beholding the spectacle of a mayfly hatch.

The mayfly in this picture is Ephemera danica, the UK's biggest mayfly and a popular model for fishermen's flies.
What a difference a day made
Twenty-four little hours
Brought the sun and the mayflies
Where there used to be rain
My yesterday was blue, dear
Today I'm part of you, dear
My lonely nights are through, dear
Since you said you were mine
What a difference a day makes
There's a rainbow before me
Skies above can't be full of mayflies
Since that moment of bliss, that thrilling kiss
It's heaven when you find mayflies on your menu
What a difference a day made
And the difference is mayflies

*Oh yeah, next May