Lacewings are straightforward little insects. They are small, not very showy and don't appear at first glance to be anything remarkable. You probably wouldn't even notice them in a walk through the garden--that is unless you are the gardener.
Gardeners love lacewings, especially the green ones. Their larvae feed on aphids, thrips, spider mites, mealybugs, leafhoppers and the eggs of caterpillar moths. Gardeners take the trouble to provide the adult lacewings with their favorite food sources-pollen and nectar-so that the predacious larvae will hatch in the garden and get right to work.
The larvae are tiny when they hatch from the egg, and only grow to about 3/8" long. Despite this small size, lacewing larvae will consume about 200 soft bodied insects a week. They attack their prey by seizing them with their (relatively) large jaws and injecting them with paralyzing venom. They can then suck out the body fluids of the prey through their hollow jaws.
Lacewing larvae are the most voracious beneficial garden predator for their size, and are used successfully in many types of gardening and crop production. You can buy them for release in the garden if they don't occur naturally.
The larvae stage only lasts about 3 weeks. The larvae will then spin a silk cocoon in which to pupate. About 5 days later, an adult lacewing emerges.
Adults of both sexes transmit messages to attract a mate. They do this by vibrating their abdomen, sending pulses down through their legs and onto the leaf they are standing on. A potential mate has to be nearby to receive the message.
The female has an interesting way of laying her eggs. She attaches her eggs to the end of long stalks made of silk so that ants and other crawling insects can't get to them. She will lay up to 300 eggs, and once a clutch of eggs is laid the overall effect is much like a pincushion.
Lacewings are a large group of insects including over 5,000 species. All have four heavily veined wings from which they get their popular name.
Lacewing larvae often find themselves under attack from ants. They will attempt to defend themselves by swinging their abdomen around and depositing a drop of defense chemical from their anus onto the ant. Some have been known to try to hide under the empty skins of their prey.
Adults are mostly nocturnal, and during the day when they are inactive they are very still with their veined wings covering their body, blending them in with their surroundings. They would be easy prey for bats at night if it weren't for the fact that they have a hearing organ of sorts within the veins of their wings that can pick up the high frequency pips emitted by bats.