Neuroptera: lacewings and antlions

Characteristics
Lacewings are delicate looking, soft bodied insects with a wingspan ranging in size from 5 to 150 millimetres and a body up to 50 millimetres in length. As their name suggests their wings appear lace-like with many intricate veins across their entire surface. Lacewings can be recognised by the following features:

• Elongate, soft body

• 2 pairs of membranous wings of relatively equal size

• Complex wing venation with main vein forked along the bottom edge of the wing. Wings are held tent-like over the body when at rest

• Mandibulate mouthparts

• Relatively large compound eyes

• Often long, filiform antennae, which may be clubbed in some species

The larvae of lacewings, many of which are commonly known as antlions, appear very different from the adults and vary greatly in shape and size depending on the species. The larvae are grub-like with large jaws projecting from the front of the head, which are used to seize their prey.

Lacewings may be confused with dobsonflies or alderflies (Megaloptera) but can be distinguished from these insects by the presence of forked veins. They may also be confused with stoneflies (Plecoptera) and dragonflies (Odonata) but lack the two thin abdominal cerci that stoneflies possess and usually have longer antennae and softer bodies than dragonflies.

Life Cycle
Mating in lacewings is direct and females usually lay their eggs on or in the substrate. Many species lay their eggs on the end of thin stalks, which may be attached to wood, leaves or other surfaces such as the windows and walls of houses. After hatching the larvae moult on average 3 times (sometimes 4 or 5 depending on the species) before they spin a silken cocoon in which to pupate. Development is usually rapid and some species of lacewings have several generations each year, although some species in colder areas take up to 2 years to fully develop.

Feeding
Lacewings are predatory as both adults and larvae, although some species of adults may supplement their diet with honeydew or pollen. Adults mainly eat soft sap sucking insects such as aphids and scale insects. Most larvae are active predators and have modified jaws, which they use to catch small insects and suck out their insides. In the more arid regions you may have observed the small pits of antlions, which are common in sandy areas. Small insects stumble into the pit trap where they are grabbed and devoured by the antlion who is waiting just below the surface.

Habitat
Lacewings are common throughout most of Australia and can be found in almost all habitats. They are common on native vegetation, such as flowering eucalyptus and in suburban gardens and homes. Many lacewings such as the green lacewings (Chrysopidae) are often attracted to lights at night and will release a strong smelling liquid when disturbed.

CHRYSOPIDAE are known as the green lacewings and are characterised by having long, filiform antennae at least half as long as the forewings. Their wings have many rectangular cells and their bodies are mostly green. Adults are common throughout the year in many areas of the country with Chrysopa being the most common genera in Australia. Members of the family NYMPHIDAE are found only on mainland Australia, Tasmania, Lord Howe Island and in New Guinea. This is only a small family and the species are most common along the east coast of Australia.