Overview

Lacewings, commonly called green lacewings, belong to the family Chrysopidae within the order Neuroptera. This widespread family includes many genera and, depending on the source, roughly 1,300–2,000 described species worldwide. In temperate regions two genera, Chrysopa and Chrysoperla, are among the most commonly encountered. Lacewings occur across diverse habitats where vegetation supports the small arthropods that form their primary food supply.

Morphology and distinguishing features

Adults are slender insects with large, reticulated wings held roof-like over the body when at rest. Many species are green, providing camouflage among leaves, though some are brown or yellowish. Distinctive traits include long, threadlike antennae and prominent compound eyes. Tiny hairs on the wing surface reduce adhesion to spider silk, and many species possess a specialised tympanal or auditory structure at the wing base that detects ultrasonic bat calls, enabling evasive responses.

Life cycle and feeding habits

Lacewings undergo complete metamorphosis: egg, larva, pupa and adult. Females often lay eggs singly on short stalks to reduce predation and parasitism. Larvae are elongate, predatory and sometimes carry debris or shed skins as camouflage. Known colloquially as "aphid lions," larvae feed on soft-bodied arthropods such as aphids, whiteflies, small caterpillars and insect eggs. They capture prey with grasping front legs and inject digestive secretions through hollow maxillae, performing extra-oral digestion so that internal tissues are liquefied and consumed.

Behavior and defenses

Both adults and larvae show behavioural and chemical defenses. Some adult chrysopids can release unpleasant-smelling substances from thoracic glands to deter predators. When bats are detected by ultrasonic echolocation, many lacewings fold their wings and drop to escape. Their light body mass and wing microstructure also allow escape from spider webs: rather than thrashing, they may bite through silk threads and slip free with minimal vibration.

Ecological role

Lacewings are important natural enemies in many ecosystems, helping regulate populations of plant-feeding pests. Their presence in hedgerows, field margins and crop canopies contributes to biological control services that benefit agricultural and horticultural systems. Both larvae and some adults consume pests, although larvae typically account for most predation.

Use in biological control and integrated pest management

Because of their predatory habits, lacewings have been used in biological control programs in greenhouses, orchards and field crops. They are sold commercially as eggs, larvae or adults. Successful use depends on timing releases to match pest abundance, ensuring suitable habitat and alternative food (such as pollen) for adult survival, and reducing harmful pesticide exposure. Lacewings are one component of integrated pest management (IPM) rather than a standalone solution.

Taxonomy, communication and research

The family Chrysopidae is part of the ancient neuropteran lineage and is the subject of taxonomic and behavioural research. Some species of Chrysoperla use substrate-borne vibrational signals for mate recognition. Ongoing studies investigate species boundaries, life history variation, and interactions with other predators and parasitoids to improve conservation and biological control outcomes.

Practical considerations for growers and naturalists

To encourage lacewings, provide diverse flowering plants that supply pollen and nectar for adult nutrition, reduce broad-spectrum insecticide use, and maintain habitat complexity. Monitoring larvae and adults can inform whether augmentative releases are needed. When buying commercial lacewings, check supplier quality and release recommendations to match local pest pressures.

Further reading and resources

For identification, observe wing venation, body coloration and larval habitus; consult regional keys when precise species-level identification is required. The biology and usefulness of lacewings make them a familiar subject for entomologists, farmers and naturalists interested in sustainable pest management and biodiversity.