Sunday 17 March 2013

Green Lacewing

Image: Stephen Ausmus
Ah! The ubiquitous and rather beautiful Green Lacewing! If you ever leave the light on at night, you will probably see this lovely sliver of green fluttering around. But did you think of the children? The beastly, beastly children?

Green Lacewings are a couple thousand members of the family Chrysopidae, with wingspans ranging between 6 and over 60 mm (0.2 to 2.4 in) across. They can be found all over the world and belong to the order Neuroptera, a remarkably fascinating yet lamentably little spoken of group called the net-winged insects.

Image: cotinis
A close look at a Green Lacewing shows you the almighty kerfuffle of lacy, network lunacy that makes up their wings.

Image: Malcolm Storey,
Lace wings
Basically, they fly by very quickly flapping pieces of the internet. Only there's less smut and fewer shysters. Which is weird because it means they're simultaneously more open and honest and more covered and clothed...

Image: BugMan50
It doesn't take much to see where the Green comes from. It comes from the fact that they're green. It's taken us a long time to get to grips with this "speech" business and no-one's gonna stop us from calling a green thing a "Green Thing". Yay, us!

Image: Gilles San Martin
Adultes se nourrissent de Chrysope Verte... Mon Dieu! I mean adult Green Lacewings have quite a wide diet, feeding on nectar and pollen as well as aphids, mites and other tiny beasties. So they can eat what the flower has to offer and then finish off a whole bunch of insects who are also eating what the flower has to offer. That's a great deal!

Of course, Green Lacewings are themselves tiny beasties, which is why they must defend themselves against slightly larger beasties. One way of doing this is by being nocturnal, which is effective against most birds. They can also release a stinky fluid when disturbed. At night, it's the bats that are the problem. Green Lacewings can actually hear the screech of bats that use echolocation, at which point it's time for evasive manoeuvres - they close their wings and fall to the ground.

So it's all stench, darkness and falling for our poor, delicate Green Lacewing, but at least that hearing ability comes in handy. It's achieved by the tympanal organ at the base of the front wings. They're basically drums; a frame with a membrane across, an air sac behind and lots of nerves to sense vibrations.

Having no desire to let a good thing go to waste, Green Lacewings use sound for communication and courtship. They "tremulate", which is an old word for "tremble in fear", only they do it a little more lasciviously. It's all about... you know.

The sound they produce is much more difficult for us to hear than that of crickets and grasshoppers, but sometimes the only difference between two species of Green Lacewing is the song that attracts them. They are otherwise almost completely identical. Kinda like teenagers.

When all's sung and done, the female lays a couple hundred eggs on the end of stalks on the underside of leaves. The rigid, silk stalk protects the eggs from ants and other ne'er-do-wells. Eventually they hatch. Many would wish they didn't...

Image: USDAgov
Larval Green Lacewings are aggressive, voracious brutes. Forget the lovely shades of green, the big round eyes and the precious wings - the larvae can barely see or hear or do anything other than walk, feel and eat.

So off they go, swaying their head back and forth like a mad thing. When they touch upon the soft, plump body of an aphid, they brutally pierce it with their long, hollow mandibles. They then inject digestive enzymes such that the aphid melts away in its own exoskeleton. Now the larva can suck up the slurry, flick the husk away and strut on in search of new victims.

Image: Miroslav Deml
And there are a LOT of victims. Some species can eat hundreds of aphids every month, leading some to call them Aphid Lions or Aphid Wolves.

Image: allencraig
Real wolves sometimes get in trouble for killing sheep and cattle, and it's no different for Aphid Wolves. Ants don't like their cattle getting killed!

Image: dpamlin
So some larvae have long bristles on which they place debris and aphid corpses. To serve as camouflage, you understand. It's not just because they're brutal sickos. No, sirree. Good thing actual wolves haven't caught on to this trick!

Image: David Illig
It's a whole bungalow here! Jaws on the right
Eventually, the killing must stop. Our heroic psychopath lays down his sweet, vicious, little head and pupates. They rest for several weeks, dreaming blood-thirsty dreams before finally, an adult emerges...

Image: JJ Harrison
She flutters her antennae and flies off into adulthood. Yes, to eat yet more aphids, but also to smell the flowers. And eat them a little.


TexWisGirl said...

okay. those children are not cute nor pretty! grow, babies, grow up!

Joseph JG said...

Haha! The "ugly" duckling doesn't know how good he had it!