Lacewings are delicate insects belonging to the order Neuroptera, recognized by their intricately veined, translucent wings. Both green and brown varieties are highly valued by agriculturalists and home gardeners for their predatory nature. The immature stage, known as the “Aphid Lion,” is highly effective at controlling garden pests. Understanding the distinct dietary needs of the lacewing throughout its life cycle is important for natural pest management.
The Voracious Larval Diet
The lacewing larvae are the primary predatory stage, actively hunting soft-bodied pests immediately after hatching. These alligator-like immatures are voracious, consuming hundreds of pests during their two- to three-week developmental period. Their diet includes agricultural pests such as aphids, mealybugs, thrips, and scale insects.
Larvae also target spider mites, whiteflies, and the eggs of pest insects, making them generalist predators valuable for controlling multiple threats. A single larva can consume 200 to 300 aphids before reaching the pupal stage. This high consumption rate makes them effective biological control agents.
The lacewing larva employs a unique feeding mechanism to subdue its prey. It possesses a pair of prominent, sickle-shaped, hollow mandibles. The larva uses these sharp jaws to pierce the body of its victim, such as an aphid or mite.
Once the prey is impaled, the larva injects digestive enzymes directly into the soft body. These enzymes rapidly liquefy the internal contents, which the lacewing then sucks back through the hollow mandibles. This process allows the larva to process its meal quickly, leaving behind only the shriveled, empty husk.
The Specialized Adult Diet
Upon reaching maturity, the lacewing undergoes a significant dietary shift, moving away from predatory larval habits. Adult green lacewings primarily sustain themselves on non-animal food sources, providing the carbohydrates and nutrients necessary for flight and reproduction. Their main energy sources are plant-derived sugars found in nectar and pollen.
Adults also feed on honeydew, a sugary waste product excreted by sap-feeding insects like aphids. This diet positions the adults near aphid colonies, ensuring newly laid eggs hatch close to a food source for the emerging larvae. While some green lacewing adults are mildly omnivorous and may consume small insects, their diet focuses on sugary and protein-rich plant materials.
Practical Application: Lacewings as Natural Pest Control
The lacewing’s predatory larval stage is a component of integrated pest management (IPM) strategies for farmers and gardeners. Because the larvae are generalist feeders, they suppress a broad spectrum of pests across various crops and environments. These beneficial insects can be introduced through commercial release programs.
Growers commonly purchase lacewings as eggs or newly hatched larvae to ensure the predatory stage is present when pest populations are active. Larvae are effective for immediate treatment of localized infestations, while adults establish a breeding population for season-long control. Release rates typically range from 50 to 250 individuals per thousand square feet, depending on pest pressure.
Gardeners can attract and sustain natural lacewing populations by providing suitable habitat and food sources for the adults. Planting flowering species such as dill, fennel, yarrow, and coriander provides the nectar and pollen required for longevity and egg production. Avoiding broad-spectrum insecticides is important, as these chemicals eliminate lacewings along with the target pests.