A green lacewing in your house is harmless and almost certainly wandered inside by accident, drawn to your lights at night or seeking shelter from cold weather. These delicate, pale-green insects with lacy, translucent wings look unusual enough to cause alarm, but they pose no threat to you, your pets, or your home. They don’t eat wood, fabric, or food in your pantry, and they won’t establish a colony indoors.
Why Green Lacewings Come Inside
Green lacewings are strongly attracted to artificial light. If you leave porch lights on or have bright interior lights visible through windows, adults will fly toward them and slip through open doors, gaps in window screens, or cracks around frames. This is the most common reason you’ll spot one indoors during warm months.
In fall and early winter, the motivation shifts. Green lacewings overwinter as adults, seeking out dry, dark, sheltered spots like leaf litter, sheds, garages, and attics. Your home looks like ideal winter housing. During this dormant period (called diapause), some species actually change color from bright green to a brownish or yellowish tone, so you may not even recognize them as the same insect you saw in summer. They aren’t breeding or feeding during this time. They’re just waiting out the cold.
How to Identify Them
Adult green lacewings are about 12 to 20 millimeters long with slender, soft bodies and large, net-veined wings that fold tent-like over their backs at rest. Their eyes are typically a striking golden or copper color. They fly slowly and somewhat clumsily, often ending up on walls, ceilings, or light fixtures. If you’ve ever noticed a faint, unpleasant smell after handling one, that’s a defensive odor some species release when disturbed.
If you spot a tiny, grayish-brown, alligator-shaped creature on a houseplant instead, that’s the larval stage. Lacewing larvae look nothing like the adults. They’re about 1 to 8 millimeters long with prominent curved jaws that they use to impale small insects and drain their body fluids. They sometimes carry debris on their backs as camouflage, earning them the nickname “trash bugs.”
Are They Dangerous?
Green lacewing adults do not bite. The larvae, with their tiny pincer-like mouthparts, are technically capable of nipping human skin, but this is rare and amounts to nothing more than a minor irritation, similar to a small scratch. There’s no venom involved, and no risk of infection beyond what any minor skin break carries. They are not toxic to cats or dogs.
Green lacewings also don’t damage anything in your home. They won’t chew through screens, lay eggs in your carpet, or infest stored food. An adult that ends up indoors is essentially lost. It would much rather be outside near flowers and other vegetation.
They’re Actually Beneficial
Green lacewings are one of the most effective natural pest controllers in gardens and on houseplants. The larvae are voracious predators of aphids, spider mites, mealybugs, thrips, small caterpillars, scales, and leafhoppers. A single larva can consume hundreds of aphids during its roughly two-to-three-week development period before spinning a small silken cocoon to pupate.
Adults of some species also eat small insects, while others feed only on nectar, honeydew, and yeasts. If you have houseplants struggling with aphids or mealybugs, a lacewing larva indoors is doing you a favor. Gardeners and farmers actually purchase lacewing eggs and larvae to release as biological pest control.
How to Remove Them
The simplest approach is the cup-and-paper method: place a glass or cup over the lacewing where it’s resting, slide a piece of paper or thin cardboard underneath, and carry it outside. They’re fragile and slow-moving, so this is straightforward. If one is fluttering near a light, turning off the indoor light and opening a nearby window or door with an exterior light on will usually guide it out on its own.
For lacewings that have settled into an attic or garage for the winter, there’s no urgency to remove them. They’re dormant, not reproducing, and will leave on their own when temperatures warm up in spring. Adults live one to three months under normal conditions, though overwintering individuals can stretch that timeline by entering their dormant state.
Keeping Them Out
If you’re regularly finding lacewings indoors, a few changes will reduce visits significantly:
- Switch outdoor lighting. Yellow or warm-toned “bug lights” attract far fewer flying insects than standard white or blue-toned bulbs. Moving porch lights away from door frames also helps.
- Check screens and seals. Inspect window screens for small tears and check weatherstripping around doors and windows, especially as fall approaches.
- Reduce light leakage. Closing blinds or curtains in the evening keeps bright interior light from drawing insects toward your windows.
Pesticides are unnecessary and counterproductive. Killing lacewings around your home eliminates one of the best natural defenses against garden pests like aphids. A stray lacewing on your ceiling is one of the least problematic insects you could find indoors.