Insect death: causes, consequences and insect protection in your own garden

Insect death: causes, consequences and insect protection in your own garden

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The number of insects in Germany has shrunk by around 80%. If the insects and thus the base of the food chain fail, the consequences would be catastrophic: the plants die with them because bees, bumblebees or butterflies no longer pollinate them.

A world without insects?

There were no apples, no pears, no plums, most of the fruits and vegetables fell out. The flowers are also dying out. Animals that eat insects disappear, as do herbivores. Smelly animal carcasses lie around because no more insects eat them, as well as feces and putrid organic waste products. Josef Tumbrinck from NABU North Rhine-Westphalia says: "If we don't have the flying insects, the entire food chain is at risk: flowers and trees are no longer pollinated and swifts and swallows lack the food base."

Decline for decades

There are around 33,000 species of insects in Germany. 7,800 of them are on the Red List of Threatened Species, many of which have already died out. In addition, 40% of all insect species continuously decrease in their populations.
In the wild bees even more than half of the species are endangered, 233 of the approximately 550 species decreased in their populations, also almost 30% of the hoverflies, 35% of the grasshoppers, 37% of the ground beetles and a whopping 87% of the water beetles.

Beetle populations declined by 75% over ten years, with half of the species losing more than 30%.

Insects are disappearing all over Europe. Butterflies across the continent have declined by 11% in 25 years, and grassland butterflies by as much as 19%.

All insect groups affected

Ecologist Josef Settle summarizes: ““ The decline does not seem to be limited to certain groups of insects. It affects practically everyone who feeds directly on plants, for example butterflies or leaf beetles, as well as predators living on them, such as dragonflies, and probably also parasites. ”

Bees and bumblebees are particularly affected: “Honeybees and wild bees such as bumblebees are also affected by the pollen intake. The pollinators are also touched. Bee deaths have been reported many times. Neonicotinoids also play a critical role in this. ”

Bird extinction indicator

The populations of certain bird species provide an indirect indication of the insect population in that they are better examined than insects. The findings are clear here: The greatest declines in the past 25 years have been in bird species that rely on insect and spider nutrition during the breeding season. Their numbers have dropped even more dramatically in the past twelve years.

Causes of insect death

Agriculture is the main reason for the decline in insects, more precisely: all primary causes of insect death are related to agriculture. These include monocultures that deprive insects of food and nesting opportunities, pesticides that directly destroy or damage insects, and the extreme use of fertilizers that change the composition of plants. Insect mortality is itself an indicator of the destruction of microhabitats.

Other causes are climate change, the sealing of areas, building and the tearing apart of living spaces for settlement and commercial construction such as industry.

The biologist Josef Settele says: “There are probably a whole bunch of reasons. The use of pesticides in agriculture is often mentioned first. Other factors are monocultures in the agricultural sector, the loss of hedges and margins in the fields. Climate change may also play a role. The dilemma is there is probably no reason. Climate change will certainly have a noticeable impact in the medium term, but can currently only explain local phenomena well in rare cases. "

What are the consequences of insect death?

Insects are central to humus, to pollinate plants and to keep the soil fertile. Insects are needed for many plants to survive. These are also essential for birds, reptiles and mammals.

NABU NRW writes: “In North Rhine-Westphalia, the population of bees, butterflies and hoverflies has decreased by around 80 percent since 2000. While the causes of insect death are being discussed controversially, the consequences are obvious: several bird species such as swallows and swifts are no longer able to find prey and many domestic (useful) plants can no longer be pollinated; there is a risk of crop failures. "

Requirements of the nature conservation association

NABU demands that agricultural policy in the EU be fundamentally reformed and that agriculture should only be subsidized with tax funds if it is compatible with nature. For example, farmers who take measures to protect birds such as insects should find support, but subsidies for large-scale use of pesticides should no longer exist.
Since the redistribution of 60 billion euros is involved, NABU is aware that there will be non-objective attacks against these plans.

Illegal farming

The NABU says that many farmers illegally expand their arable land to the streets and thus also occupy property of the municipality, district or country. The municipalities are often not interested in taking care of this, and clarifying the legal claims is associated with extensive measuring of the wayside edges. By expanding the fields, the farmers are destroying the edges of the path that are important for insects, birds, reptiles, amphibians and small mammals, whose microhabitat gives the wild flowers habitat that modern agriculture drives away from the fields.

Legal basis

There have long been legal foundations to counteract this overexploitation of refuges for wildflowers and insects. According to the Roads and Paths Act of Schleswig-Holstein, section 18a “Road and path edges and noise barriers should be preserved and designed in such a way that they can develop in a natural way. Their entertainment should focus on the importance as part of the biotope network systems. The road residents must tolerate all the necessary measures, provided that there is no expropriation effect. ”


The illegal appropriation by farmers is only one reason for the destruction of the waysides with their daisies, flakes and cornflowers, way attendants or St. John's wort. Another reason is the extreme spreading of liquid manure on the fields. This will release ammonia into the air. Although this promotes blackberries and nettles, these dominant plants ensure that the “weaker” wild perennials can no longer spread.


Another reason for the destruction of microhabitats is mowing, which farmers and local authorities do too often in many places. In contrast to private gardeners, the restrictions of nature conservation law do not apply to municipalities and "professional" nature users such as farmers or anglers.

The Bavarian biologist Josef Reichholf criticizes that nature-loving citizens are not allowed to take bird feathers home or bring frog spawn into the garden pond, while at the same time municipal employees mow meadows, clear hedges and dry up wetlands that provide the animals with a habitat.

Field border strips

In an effective agricultural technology, which reduces the number of wild plants in the fields to 1% of the crops, field border strips are of particular importance. The purpose of such sown flower strips is to relieve the soil.

High land prices

However, the high land prices mean that farmers also fully exploit poor soil. They are suitable for maize cultivation, which has been booming for years. The EU, the federal government and the federal states promote edge patrol programs through subsidies from farmers, but the cultivation of maize promises higher profits. Farmers are not legally obliged to create border strips.

Depending on the structure of the soil, plants on the verge that provide food for insects are, for example: tansy, plantain, rocket, pathway, corn poppy, yarrow, snake head, nettle, mugwort or scratch thistle.

Forage plants for butterflies

Forage plants for butterflies are, for example, leaf clover, crown vetch, wild carrot, borage, field man litter, cypress spurge, meadow widow flower and musk mallow. Neozoa such as summer lilac, giant hogweed or Canadian goldenrod also offer butter rich nectar, but are unsuitable as feed like the caterpillars.

The cornell cherry

The fruits of the cornell cherry served our ancestors as an olive substitute. It is ideal for planting slopes and gaps. The wood has great value as a bumblebee, butterfly and bee pasture because it blooms early.

What to do about insect death?

Everyone can do something about the death of insects. NABU writes: “For example, farmers can plant wildflowers between their fields and use natural pesticides, while beekeepers can give their colonies better health prophylaxis. (Interestingly, nicotine protects bees from parasites and infections.) Balcony and garden owners can help prevent insects by avoiding pesticides. Likewise through nesting aids such as insect hotels, but this variant only makes sense if your own garden is exemplary in terms of biodiversity. "

Insect-friendly plants

On your own balcony or in your own garden, you can look out for insect-friendly plants. The biologist Jürgen Tautz from Würzburg sums it up: “Throw the geraniums from the balcony! What looks nice is not always good for insects. Geraniums provide neither pollen nor nectar. ”

Stuffed plants show particularly lush flowers, but do not contain pollen because the nectaries are mutilated. Such breeds include certain roses, asters, chrysanthemums, dahlias, carnations, peonies or camellias.

Diversity in the garden

Insects love wild flower boxes, in which mugwort grows, for example, which provides food for 150 insect species. Even unsprayed apple trees are paradises for the little animals, while intensive plantations with sprinkled apples offer no living space for them.

They help a lot if you do not use artificial fertilizers in the garden and on the balcony. You can use plant-based weed killers and fertilizers instead.

Insect hotels

Insects are increasingly suffering from a loss of nesting opportunities. Insect hotels offer you an alternative. They consist of wood, tree bark, reeds, cones and stones and provide shelter for bumblebees, wild bees, ladybirds, lacewings or butterflies.

How do you create diversity?

Plant native shrubs and flowering bushes, sow wildflowers. A box on the balcony is enough for wildflowers.

Insects can also use many originally foreign plants as a source of food, but evolution has leveled them and regional plants very closely together. So there are flowers that can be pollinated by only one species of butterfly. Caterpillars in particular are often specialized in a single plant. For example, the American scarlet thorn feeds only two species of bird in Germany, while the native hawthorn 32.

Fall foliage and dead wood

Be sure to leave fall leaves in certain places in the garden. It is a lifeline for insects and insect larvae. Deadwood offers habitat for various beetles, parasitic wasps, bumblebees, bees and ants. The animals living there generally do not cause any damage to the trees and bushes because they specialize in dead wood.

Hedge with subsoil

They create an ideal habitat for insects, small mammals, some amphibians and birds if they leave dead wood in one place in the garden until blackberries overgrow it, unload fruit and hedge trimmings and plant sloes like wild roses around. Slow crawls and robins, bumblebees and wild bees will thank them.

Nesting aids for wild bees

You can help wild bees with simple means. For example, they drill holes in slices of oak, beech or other deciduous trees that lead about 10 cm into the wood without leading out on the other side. These tubes should be up to 8 mm thick. Hang these panes in a sunny and dry place, for example on a south-facing wall of a house.

Stems, stones and stalks

You can also tie reeds, elder branches or the stems of perennials like hollyhocks together or fill them in a box with an opening and hang them in a place protected from rain.

Alternatively, you can use perforated bricks or stones, fill the holes with clay and drill small passages with a twig.

Flower pots

For bumblebees, half fill large flower pots with dry moss, close the opening with wire mesh and dig in the pots so that the water hole protrudes a finger's breadth from the ground.

Old piles

Do you have an old pile lying around? Outstanding. This is the XXL version of the wooden disc. Drill additional tubes for bees and bumblebees to the passages that beetles have eaten into.

Insect hotel does not have to be

A bought or self-built insect hotel in your own garden or on the balcony is good and nice, but remember what it is made of and do not ban these "raw materials" from their surroundings.

Anyone who leaves a pile of dead wood in the garden, creates a layer of leaves like a dry wall, provides a pile of stones, a brushwood bed, a "wild" compost pile, a raised bed with a hedge and fruit cut as a base, leaves old branches on the tree, and the perennial stems not cutting off until next spring, which offers on many square meters what an insect hotel imitates as a micro model.

Dilapidated garden huts

The "ideal" for a shelter from insects would be a dilapidated garden shed with holes in the roof, clogged rain gutters, "mess heap" from old tools and the accumulation of natural elements, with overturned rain barrels and broken wheelbarrows, wooden deckchairs that are decaying, etc. Since you are in but also want to feel comfortable in your garden, don't let it get that far.

But at your garden shed you can look for free space for insects on and around the hut. If you don't like clutter, an "insect garden" can also be kept tidy.

Baskets, boxes and firewood

For example, you can store clippings in wicker baskets or wooden boxes, stack firewood in a dry place but with free access to the outside, decorate slate plates on the garden pond so that openings remain free, through which insects can pass.

If you do not want wildflowers to "rampant", you can also place them in hanging baskets, flower boxes or special raised beds.

Leave in silence

Many traditional gardeners find it difficult, but more important than all insect hotels is to simply leave corners in the garden in peace. Since they are native plants, many food plants of the insects spread by themselves, and shelters arise on their own when the raspberry leaves wither at the garden pond and the leaves fall over them in autumn. (Dr. Utz Anhalt)

Author and source information

This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.


  • Segerer, Andreas H .; Rosenkranz, Eva: The great dying of insects: what it means and what we have to do now, Oekom Verlag, 2018
  • Angres, Volker; Hutter, Claus-Peter: The silence of nature: The uncanny disappearance of insects, birds, plants - and how we can stop it, Ludwig Buchverlag, 2018
  • NABU - Naturschutzbund Deutschland e.V .: (accessed: October 19, 2018), fewer bees, flies, butterflies
  • Hallmann, Caspar A. et al .: "More than 75 percent decline over 27 years in total flying insect biomass in protected areas", in: PLoS ONE, Volume 12 Issue 10, 2017, Plos | ONE
  • State Association for Bird Protection in Bavaria (LBV) e. V: (accessed: October 9, 2018), The consequences of insect death

Video: The great death of insects. DW Documentary ecology documentary (October 2022).