Many hobby gardeners are familiar with lacewings because the insects are used in natural pest control. However, the animals have many secrets. Their life cycle is as exciting as their diet. Lacewings are by no means boring, as they have even developed special communication techniques.

Lacewings are used in the biological fight against aphids

Table of Contents

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  1. the essentials in brief
  2. Beneficial or harmful?
  3. distribution and habitat
  4. food
  5. Characteristics
  6. lifestyle and development
  7. species
  8. combat?
  9. Encourage lacewings
  10. build a nesting aid
  11. Natural garden
  12. breed and use
  13. frequently asked Questions

    14. the essentials in brief

    • Lacewings are helpful beneficial insects in the garden because they suck out aphids
    • Therefore, lacewings are bred in four places or attracted with the help of insect hotels or nesting boxes
    • Lacewings are capable of biting humans, but extremely rarely do so
    • Due to its usefulness, however, combating it should be avoided in any case

    Beneficial or harmful?

    Lacewings are beneficial in both agriculture and forestry. They are bred in large numbers for their importance in biological pest control. The larvae of the lacewings help against aphids, because they mainly feed on the plant pests and are therefore referred to as aphid lions. However, they are not choosy and will hunt for spider mites, mealybugs, thrips, whiteflies or other small insects.

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    Are lacewings dangerous?

    Larvae have pincer-like mouthparts that they use to grab their prey. There are observations that the larvae also bite people. Itching and inflammation can occur at the bite site. It is not yet clear why the animals prey on humans. Researchers suspect that the larvae suffer from a lack of food during long periods of drought and expand their prey scheme. Bites are also possible as a result of defense reactions.

    Most lacewing species no longer exhibit a predatory lifestyle in the adult stage. There is no evidence that humans have been bitten by adult lacewings in the past. Their mouthparts are used to pierce plant tissue and suck out the sap. They are of no benefit if they bite human skin. Lacewings are not poisonous and are therefore classified as harmless.

    distribution and habitat

    Lacewings are found worldwide. The common lacewing occurs both in the lowlands and at higher altitudes. From spring to autumn she lives in the low vegetation of open fields and corridors. It prefers habitats with species-rich vegetation. Old deciduous trees serve as winter quarters.

    In house and apartment

    When winter is just around the corner, lacewings look for suitable crevices to hibernate. This allows them to get into apartments and houses. During the cold season it can happen that the animals are disturbed by light sources. After short flights in the apartment, the animals quickly crawl back into their hiding place.

    food

    The majority of all lacewings feed on nectar, pollen and honeydew when fully grown. Almost all larvae are predatory like the species of the genus Chrysopa. They hunt for smaller insects such as aphids or mites. If there is a lack of food, the larvae prey on larger organisms such as ladybird larvae. Even conspecifics are not spared.

    Larvae eat large quantities of insects, with differing information on the exact number. These range from 150 insects within one development up to 100 prey animals per day.

    Characteristics

    Lacewings are a family within the lacewings also known as gold-eyes. The species received this nickname because of the metallic-bronze colored shine of the compound eyes of some species. There are around 2,000 different species in total, 70 of which are found in Europe. 35 species are native to Central Europe. The common lacewing (Chrysoperla carnea) is the best-known species. The family was named after the net-like wing pattern, which is also known as the pile.

    digression

    A look at the taxonomy

    Strictly speaking, Chrysoperla carnea is not a single species but a complete aggregate of several small species. Researchers came to this conclusion because of the courtship songs that the insects produce with their abdomens during the mating season. However, the exact identification of the species is extremely difficult, because the courtship songs sometimes seem to differ between individuals that look the same.

    features

    The most striking feature of the lacewings, which distinguishes all lacewings, are the wings that are bent downwards. They do not have a widened pronotum. In lacewings, this abdominal segment bends sideways up to the front legs. Lacewings differ from other lacewings in the pattern of the transparent wings. Rarely are the wings spotted or provided with a drawing. Central European species are predominantly green or brownish in color. They differ in their head markings.

    Lacewing wingspan:

    • Central European species: six to 35 millimeters
    • tropical species: more than 65 millimeters

    The lacewing is a very beautiful, delicate insect

    larvae

    Lacewing larvae have an elongated body, the sides of which are occupied by weakly developed protuberances. There are some species whose larvae have a squat body and are equipped with hooked bristles. This hair is used for camouflage by sticking to it various materials or prey remains.

    lifestyle and development

    Lacewings are active at dusk or at night. They can communicate with other animals by vibrating their abdomen. This touches a background, which in most cases represents a leaf. Species of the genus Chrysopa respond to ultrasound by flapping their wings against their bodies and falling to the ground. This behavior is a protection against natural predators such as bats, which use ultrasound to sense their prey.

    egg laying

    Females lay their eggs individually on stalks up to ten millimeters long. In this way, a female can attach between 100 and 900 eggs in suitable places. They choose places where the larvae are well cared for. Females therefore prefer aphid colonies as a place to lay their eggs.

    larval development

    The first moult of the larvae occurs immediately after hatching. They then move on the plant to find food. Your mode of locomotion seems aimless. The larvae tilt their heads in all directions until their jaws encounter prey. The contact triggers a stimulus that causes the larvae to grab.

    They lift the prey with their mouthparts and inject a digestive secretion. An aphid is decomposed from the inside within 90 seconds and the larva can suck out the prey.

    Lacewing larvae suck out aphids

    Life expectancy

    Depending on the environmental conditions, the development of the larva lasts between eight and 22 days. Temperatures between 20 and 26 degrees Celsius favor the development of the larvae. Normally, the life expectancy of a lacewing is two to three months. The common lacewing is able to overwinter. She can reach an age of eight months.

    wintering

    Central European species overwinter in a prepupal stage, which they spend in a double-walled cocoon. Only the common lacewing overwinters as an adult insect. To prepare for winter, it changes color from green to brown between September and October. Your metabolism is severely throttled. It does not survive the winter in heated rooms. Natural enemies and too low temperatures increase the mortality rate, which is between 60 and 90 percent in winter.

    Overwintering quarters:

    • under the tree bark
    • cool roof trusses and apartments
    • Niches in gazebos and barns

    species

    Lacewings are difficult to tell apart. Most species have a greenish shimmering body and prominently veined wings with green veins. There are also brownish or black types.

    Some lacewings are able to change color throughout the year. Shades of green turn to light brown just before winter so that the animals are better camouflaged in nature. After hibernating next spring, the animals turn green again. The habitat can also give an indication of the species.

    coloring habitat
    Common lacewing green and brown warm mixed deciduous forests
    Mediterranean lace fly green all year round pine or pine forests
    Red-headed lacewing dark brown with a red head warm mixed deciduous forests

    The red-headed lacewing is characterized by its red head

    Do lacewings have to be fought?

    Lacewings are extremely useful insects and should not be fought. Reports of biting larvae are rare and do not reflect the animals' typical lifestyle. Lacewings are not usually a nuisance as natural weather conditions and predators keep their populations in check.

    tips

    If you spot a winter lacewing, do not disturb the animal. In the spring, you can give the insect free flight by opening windows and doors.

    Encourage lacewings

    In the 1980s, intensive studies were carried out at the University of Bonn, which examined the suitability of various winter quarters for lacewings. Experiments have shown that lacewings are attracted to red and brown shades. The insects preferred models with a side length of 30 x 30 x 30 centimeters that were filled with straw. In such quarters, the mortality rate during the winter could be reduced to five to eight percent. The nest boxes are also inhabited by ladybird larvae.

    Buy an insect hotel

    It has been found that the vast majority of models on the market are not used by lacewings. If you decide to buy an insect hotel, you should pay attention to minimum dimensions, structure, paintwork and interior design. Don't let the price tempt you to order. High-quality models that are actually suitable as winter quarters for lacewings do not come cheap. There are some variants made of wood concrete, the front of which has been provided with slats. These nest boxes are well suited.

    build a nesting aid

    If you want to encourage lacewings in your garden, you can build your own insect hotel (€11.33) using the following assembly instructions. If you paint the wood in dark red shades, you increase the chance of successful use. When choosing colors, make sure that they are harmless to people, animals and the environment.

    building instructions

    Saw three boards measuring 30 x 30 centimeters. These act as back and side panels. The roof panel should protrude slightly to prevent rainwater from running into the front opening. Plan about 32 x 30 centimeters for the roof. So that the box offers optimal protection against the cold, it should be made of solid wood.

    Both the front and the underside of the box are provided with slats pointing downwards, so that the air circulation is reduced. You can saw the slats yourself out of wood. These should be about one centimeter wide and are attached to the two edges of the side walls. Use small spacers so that the slats lie at an angle. Wooden dowels are suitable for this, which you push between the slat and the edge of the side wall.

    filling

    So that the hibernating insects are optimally protected from the cold, the insect hotel should be filled with natural materials. It turns out that lacewings like to hibernate in straw. In nature, they also look for piles of leaves or crawl under the bark. To ensure that the filling material does not fall out of the box, you should provide the front and underside with a fine-meshed wire mesh before attaching the slats.

    tips

    Attach the roof to a hinge so you can open the box again. Regular cleaning is not necessary. You can replace the old filling material after about four years.

    Hanging tips

    The location plays a crucial role in ensuring that lacewings accept the winter quarters. Hang the box at a height of 1.5 to 2 meters. A solitary tree is ideal. You can also attach the dwelling to a post or wall. Alignment is important. The front should face south so that the sun's rays warm the box. At the same time, the entry opening should not face the main wind direction.

    Natural garden

    Create a natural biotope in which lacewings automatically feel comfortable. The ideal habitat offers species-rich flower meadows that provide numerous sources of nectar. Deadwood creates ideal quarters for overwintering. Planting shrubs and deciduous trees is recommended in large gardens.

    Wild plants in the tub

    If you only have little space in the garden, you can fill flower boxes (€16.99) and tubs with wild plants. A self-built insect hotel provides the perfect retreat. Leave leaves in autumn and avoid using chemical pesticides. In a well-structured natural garden, insects find natural hiding places. They also support numerous specialized insect and bird species that complete the native biotope.

    plant list

    Catnip attracts lacewings, studies by American researchers have shown. Catnip flowers produce nepetalactone. The composition of this fragrance is similar to that of the sex attractant of adult lacewings. At the same time, nepetalactone has antimicrobial and antiviral properties. Catnip attracts beneficial insects and drives away numerous plant pests such as mosquitoes, cockroaches and fleas. Incidentally, the scent is also produced by aphids. Purple coneflowers and nectar-rich late summer flowers are also attractive to lacewings.

    Lacewings are magically attracted to catnip. This is impressive as the plant acts as a deterrent to many pests.

    breed and use

    There are now specialist companies that also deal with the breeding of lacewings. There are breeding sets with larvae and food that are intended for private use. However, breeding requires some patience and consistent attention so that adult insects develop from the larvae. If your plants are suffering from an aphid infestation, larvae are an effective control method.

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    application in the home

    Lacewing larvae are sent by post in cardboard combs or on buckwheat husks. Both variants prevent the larvae from eating their conspecifics. To ensure that they do not freeze to death, they are only shipped during the frost-free period. You can also order lacewings at the egg stage. These are supplied loose or glued to a cardboard box. Under optimal conditions, it takes about four to six days for the larvae to hatch. If the larvae hatch during shipping, there is a higher risk of cannibalism.

    Benefits of pest control with lacewings:

    • Larvae are already active at ten degrees Celsius
    • good results are also achieved with low humidity
    • The activity of the larvae is independent of light intensity and day length

    frequently asked Questions

    What is the lifespan of a lacewing?

    Lacewings go through several larval stages that usually last two to three weeks. They stop eating shortly before pupation. They then spin themselves into an oval cocoon in which they spend the next ten to 30 days, depending on the temperature. The adult lacewing begins laying eggs at four to ten days of age. She has a life expectancy of about two months. Overwintering insects can live up to eight months.

    Why do lacewings lay their eggs on stalks?

    This behavior is said to protect the larvae from cannibalism. A female can lay between 100 and 900 eggs in this way. The eggs are green in color at first. They then change color from dark green to brown. Shortly before hatching, they are colored grey-brown.

    Is a lacewing bite dangerous?

    Normally there is no danger for people and pets to be bitten by a lacewing. There are reports that the larvae have bitten into human skin. Such a sting can cause inflammation and itching. The symptoms disappear automatically after a few days. This behavior is not typical.Researchers suspect a lack of food as the trigger.

    What to do against lacewings in the apartment?

    The insects get lost in buildings when they are looking for a suitable winter quarters. They like to retire to unheated rooms and use niches and cracks as retreats.

    In winter they can be disturbed by light sources, causing them to fly around the room. After a short time they withdraw again. Since these are beneficial insects, you should not fight the animals. Give them a safe place to hibernate, because about 60 to 90 percent of all hibernating lacewings don't survive the winter.

    How can I attract lacewings?

    The insects like a natural garden that offers small-scale structures. Flowering fringes with plants that produce nectar are important. Shrubs and deciduous trees serve as winter quarters. Plant catnip and coneflowers. In particular, catnip is a coveted flowering plant among lacewings because its scents are similar to sex attractants.

Category:

Animals in the garden