Common green lacewing

Appearance

The green lacewing eggs are oval and secured to the plant by long slender stalks. They are pale green when first laid but become gray later. The larvae are about one millimetre long when they first hatch. They are brown and resemble small alligators, crawling actively around in search of prey. They have a pair of pincer-like mandibles on their head with which they grasp their prey, sometimes lifting the victim off the leaf surface to prevent its escape. The larvae inject enzymes into the bodies of their victims which digest the internal organs, after which they suck out the liquidated body fluids. The larvae grow to about eight millimetres long before they spin circular cocoons and pupate.

Adult green lacewings are a pale green colour with long, threadlike antennae and glossy, golden, compound eyes. They have a delicate appearance and are from twelve to twenty millimetres long with large, membranous, pale green wings which they fold tent-wise above their abdomens. They are weak fliers and have a fluttery form of flight. They are often seen during the evenings and at night when they are attracted by lights.

Naming

"Chrysoperla carnea" was originally considered to be a single species with a holarctic distribution but it has now been shown to be a complex of many cryptic, sibling species. These are indistinguishable from each other morphologically but can be recognised by variations in the vibrational songs the insects use to communicate with each other, which they especially do during courtship.

Behavior

The green lacewing adults overwinter buried in leaf litter at the edge of fields or other rough places, emerging when the weather warms up in spring. Each female lacewing lays several hundred small eggs at the rate of two to five per day, choosing concealed spots underneath leaves or on shoots near potential prey. The eggs are normally laid during the hours of darkness.

The larvae hatch in three to six days, eat voraciously and moult three times as they grow. They feed not only on aphids but also on many other types of insects and even prey on larger creatures, such as caterpillars. They can consume large numbers of prey and completely destroy aphid colonies. When food is scarce they turn cannibal and eat each other. After two to three weeks, the mature larvae secrete silk and build round, parchment-like cocoons in concealed positions on plants. From these, the adults emerge ten to fourteen days later. The length of the life cycle is greatly influenced by the temperature and there may be several generations each year under favourable conditions.