Lacewings are amongst the most enchanting and delicate insects encountered in the British isles and are named so for their exquisitely intricate wings, which resemble fine lace due to the network of veins that crisscross them.
These wings are typically held roof-like over their bodies when at rest, giving them a distinctive silhouette and are what gave their order the name Neuroptera, which translates as ‘nerve-wing’ or ‘net-wing’, deriving from the Greek words ‘neûron’, meaning sinew, tendon or nerve and ‘pterón’, for wing.
The most commonly encountered Lacewings in Britain belong to the family Chrysopidae, often referred to as Green Lacewings due to their vibrant emerald hue. There are 14 members of that family and altogether over 70 species can be found here including 29 belonging to the family Hemerobiidae, known as Brown Lacewings, which are smaller and less conspicuous.
Sometimes they are called ‘Stinkflies’, as they will emit a foul-smelling substance from their prothoracic glands when threatened, this contains ‘skatole’, the compound which makes mammalian scat smell so atrocious.
(Bees & Wasps of Ireland)
Leonine Larvae
Adult green lacewings are delicate and ethereal creatures, generally 1 to 2 cm in length, with long, slender antennae and large, compound eyes that shimmer with a slightly alien-looking metallic sheen.
Their larvae, however, are entirely different beasts, being voracious predators, and are often nicknamed ‘Antlions’ or ‘Aphid-lions’ pertaining to their ferocious behaviour and enormous appetite for Aphids and other small invertebrates.
These Antlions are elongated and grub-like, with powerful, over-sized jaws evolved for capturing prey. They feed insatiably for two to three weeks and then pupate in a silken cocoon, emerging as adults after about a fortnight.
In these few weeks some Antlions may dig a conical pit in loose, sandy soil and bury themselves at the bottom with only their jaws exposed. When an ant or other small insect haplessly stumbles into the pit, the loose sides cause it to slip toward the center.
The Antlion may flick sand upward to accelerate the prey’s slide but however it grabs it once the prey is seized in its powerful mandibles there is no escape, for the Antlion injects it with a powerful venom to paralyze it, and immediately proceeds to devours it alive.
by Jimmy Bugs
Sometimes the larvae may hatch near an aphid colony in which case they will roam through it with impunity attacking the hapless creatures as they go, this behaviour has given them the alternative name of ‘Aphid-lions’.
A few of our Lacewing species exercise a very clever survival technique called ‘debris-toting’, whereby they camouflage themselves by attaching debris; dead insect bodies, lichen or plant material, on their backs, making them appear less conspicuous to prey and predator, much like Æsop’s ‘Wolf in Sheep’s Clothing’ who famously donned a fleece coat in order to sneak into the flock.
it seems that spiders are in fashion this season!
Adaptable and Resilient
While Lacewing larvae are solely carnivorous, the adults have more varied diets. Many green Lacewings feed on nectar, pollen, or honeydew, though some species retain predatory habits, consuming small insects. This dual feeding strategy makes them adaptable and resilient in Britain’s fluctuating climate.
Their lifecycle is also ingenious, the female lays her eggs on stalks, a unique adaptation that elevates the eggs away from potential predators. These stalked eggs, often found on plant stems or leaves, hatch into the larvae after only a few days.
This adaptability and resilience has made Lacewing very useful to us in agriculture, as natural pest control agents. Farmers will introduce Lacewing larvae into fields or greenhouses to reduce populations of soft-bodied pests, such as aphids, mites, whiteflies, and small caterpillars, without resorting to chemical pesticides.
They can adapt as easily to a greenhouse as to a field and are happy eating whatever prey is available.
This biological control method is a sustainable farming practice as it promotes natural predator-prey relationships and minimises environmental impact. The larvae are particularly effective because they have a high feeding rate, and when they’ve pupated into adult Lacewings they will continue contributing to pollination and minor pest control.
You can even buy them for your garden, (other retailers are available, I just picked the first one I found!)
Indicative Insects
Rarer species, such as Drepanepteryx phalaenoides, the Dead Leaf Lacewing, are more habitat-specific, found only in ancient woodlands or wetlands, and their presence can indicate healthy, undisturbed ecosystems.
Their sensitivity to environmental changes, such as pesticide use or habitat loss, makes them indicators of ecosystem health, so a thriving Lacewing population often signals a balanced environment, for this they are termed bio-indicators, and commonly studied by ecologists.
Such research includes studies into how they react to changes in temperature, which tells us how climate change may affect other insect species and the wider environment. (with Lacewing an increase in temperature leads to faster development but lower survival rates)
Other studies have looked into the Lacewing’s unusual method of communication, whereby they create low frequency vibrations with their abdomens. This is a concern where Lacewing habitat is near to major roads and motorways, as they cannot detect each other’s presence over the noise and vibration caused by traffic, which affects breeding success.
(Gilles St Martin)
When are Lacewing out and about?
Seasonally, lacewings are most active from late spring to early autumn, though some species overwinter as adults, seeking shelter in leaf litter, bark crevices, or even houses. In fact it’s not uncommon to find a green lacewing fluttering around a porch light or resting on a windowsill during the colder months.
While Lacewings are not currently considered endangered in Britain, their populations can be affected by intensive agriculture and the widespread use of insecticides.
Encouragingly, their numbers can be bolstered through simple conservation efforts; planting nectar-rich flowers, avoiding chemical pesticides, and maintaining wild patches in gardens can provide lacewings with the resources they need to thrive.
For those interested in observing Lacewings, a keen eye and a bit of patience are all that’s required. Dusk is an ideal time to spot adults, as they become more active in the fading light. Alternatively, inspecting plants for their distinctive stalked eggs or searching for larvae among aphid colonies can reveal their hidden presence, and it’s worth doing so as they are fascinating insects to observe.
“That’s a good idea,” Moomintroll agreed. “He once pulled my mother down into a hole and sprayed sand into her eyes.”
(From Finn Family Moomintroll, by Tove Jansson)
At that moment a threatening head with staring eyes popped up from the hole in the sand.
“Did you say weak?” hissed the Ant-lion. “I can dig myself down in exactly three seconds!”
“You should really show us how it’s done, so that we can believe such a wonderful feat is possible,” said Moomintroll, persuasively.
“I shall spray sand on you,” replied the Ant-lion very crossly, “and when I have sprayed you down into my hole I shall gobble you up!”
(From ‘Looking for the Ant-lion and trapping him’ in Finn Family Moomintroll )
A B-H
(March 2025)
Northwest Nature and History 
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