Friday, September 30, 2011

Green Lacewing: Teenage Hellion

The common green lacewing, Chrysoperla sp., is a welcome insect in my garden and on the farm, but it sometimes reminds me of Dr. Jeckyll and Mr. Hyde.  It has rather alarming personality shifts.   It starts and ends life with delicate, gentle beauty, but it has a dramatic personality change during its ferocious adolescent stage.  

Green Lacewing Eggs
The miniscule space needles growing out of the shefflera stem above are not fungi.  They are the slim, stalked eggs of the green lacewing.  Lacewing eggs are usually laid on the undersides of leaves and stems.  They are a lovely surprise to find when working in the garden.  They seem so fragile that they would break or bend in the breeze, but you can brush your finger against them and they stand back up.  They are so delicate, that I can't feel them, even with my less calloused ring fingers.  They stand in peaceful beauty, glistening in the sun, while their infant lacewings develop inside each egg.  

Watch out, because after a few days, each egg cracks, and out charges a fierce, anxious monster of a teenage insect: the green lacewing larva.  It moves quickly and ranges widely, and it is hungry for fresh meat. It stalks, catches and eats every insect it can catch with its pointy mouth parts.  It kills its prey with toxic venom.  If it were 100 times larger, you would have to fortify your house and never go outside!  I'm certain some dangerous movie aliens are based on these ravenous killers. 

Scary green lacewing larva, source in picture.
After a few weeks, the green lacewing larva begins to feel full.  Its hunger for protein is sated.  It's ready to settle down, take up a peaceful existence and devote itself to future generations.  It finds a sheltered space under a leaf, wraps itself into a silk-bound ball, and metamorphoses into an adult.  The adult emerges, green and shimmering, and spreads its delicate, reticulated wings.  It floats off into the night, sipping nectar, mating and laying eggs.

Green lacewing adult with outstretched right forewing.
Don't fear the lacewing, even in its carnivorous stage.  It won't bite or sting you.  It will, however, remove hundreds of pest insects from your garden.  One lacewing larva can eat 200 aphids in a week!  Some organic gardeners buy and release lacewings onto their farms to help control insects.  Pesticides kill these useful farm workers, allowing pest insects to move back into the area with no predators.  Since pests can usually reproduce faster than prey, if both pests and prey are killed, you're likely to have a worse pest problem in a few weeks when the population recovers.  Encouraging beneficial insects like the green lacewing helps cut down on expenses, work and pesticide usage.  To encourage lacewings, plant flowers that the adults like, for example coreopsis, dill, Queen Anne's lace, cosmos and other similar plans.  You can also leave some of your dandelion weeds, because lacewings love them.

I apologize to my biologist readers for all the anthropomorphizing above, but these little critters seem very dramatic to me. 

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