Build an insect hotel yourself - how it works
Bees, bumblebees and wasps, butterflies and dragonflies are threatened in their population. In addition to food plants, they lack shelter. We can help with so-called insect hotels, in which we provide these nesting and winter spots.
- We offer bees, wasps and bumblebees a nesting possibility with tubes from 2.5 mm to 1 cm.
- Beetles and earwigs love dry nests made of wood wool and straw. However, these should be located away from the apiary so that the earwigs do not eat the bee larvae.
- Insect hotels can be built from different materials. It is important that these are weatherproof, do not get wet on the inside, and the holes are the right size for the animals.
- In addition to purchased materials such as bamboo, you can also collect your insect hotel utensils in the garden using stems, hardwood and tree bark.
- An insect house only makes sense if you also otherwise provide an insect garden and offer suitable nutrient plants for larvae and old animals.
Don't buy useless finished products
But be careful: Insect hotels are a hype, and every garden center offers them today. Most of these finished products are unsuitable as a habitat for the insects: sometimes the holes in the wood are too small, sometimes too short, or there are materials in them that the animals cannot do with.
The ecological niches of wild bees and bumblebees are very different. Sand bees dig their nests in sand, some bumble bees dig themselves underground. Others use the corridors in dead wood that eat beetles, some nest in tree holes or in piles of wood. Others live in crevices or cracks in walls. Then they populate the hollow stems of plants.
Today, sandy areas are disappearing under the shopping center, old houses stand in the place of old sheds and rotten trees are removed from the city administration, orchards are lost, dry stone walls are removed.
Food and shelter
An insect hotel in the manicured English lawn makes as much sense as an apartment with an empty refrigerator and without the opportunity to get something to eat. Create a wildflower meadow to shelter insects, plant a natural hedge with hazel, hawthorn, goat willow, meadowsweet, sloe and cornelian cherry.
Nesting aids for different species
If we know the needs of the individual species, we can simply make nesting aids. For example, we tie reeds together or fill the holes of a hollow brick with straws and hang everything up in a place of sun. The course should be dry, south-facing and windless.
Before you start, make sure the most common mistakes when building an insect hotel to avoid:
- If, for example, the stem nodes in the front part of stems, the animals cannot crawl through them.
- Ytong stones act like a sponge and absorb water. The insects cannot stand the wetness.
- Insects do not accept stems that are flat, frayed or split.
- Pine cones, straw or bark are of no importance for wild bees. Instead, these pull in ear pinchers.
- If you want to give both groups a home, separate the nests with cones, straw or bark from the shelters for wild bees. Otherwise the earwigs will eat the nectar stores empty.
- Clay-colonizing bees dig their own holes. That is why the clay must not be too hard. Avoid insect hotels with pre-drilled holes in the clay.
- The end of stems and tubes should be closed. If both sides are open, regardless of whether they are perennial stems, bamboo tubes or reeds, the insects will not accept them.
- Do not drill larger than 1 cm in diameter. There are no oversized insects here that would take the holes.
- Do not drill parallel to the wood fibers. The fibers can block the way of the animals.
- Choose softwood instead of hardwood.
- Gypsum concrete is unsuitable as a building material. It absorbs water and that kills the insects.
Insects and the garden benefit
An insect hotel supports:
- Wild bees: none These pollinate fruits and vegetables
- Wild bumblebees: Like the bees, they pollinate garden plants.
- Ladybug: They and their larvae eat aphids.
- Lacewing: Their larvae eat aphids.
- Ground beetle: They eat slugs and Colorado beetles.
Lacewings, earwigs and their larvae are also important food for toads, lizards and birds - that is, for the natural predators of the snails that grate away the lettuce.
Instructions for building an insect hotel
An insect shelter is best in partial shade with the openings to the south and free access - so not in the undergrowth. Full shade is unsuitable because the larvae need the sun's warmth to develop. It must not be exposed to the northwest, otherwise moisture will get into the dwellings. Mushrooms can spread and the animals die.
The hiding place is best raised, then predators cannot reach it too easily. In addition, it is usually too shady on the floor. It is best to have an insect pasture nearby, i.e. flowers or plants infested with aphids. An on-site water point is also necessary. It is better not to illuminate the space around the insect hotel in the dark. A wire mesh keeps birds out.
When do we set up the hotel?
We can set up insect hotels all year round, because they serve not only for breeding but also as winter quarters. But it is better to offer them from spring to autumn because the insects are not active in winter. Place the dwelling in a fixed place and leave it there.
Danger: Do not come up with the idea of "wanting to do something good" for the insects and to warm up the hiding place in winter. The larvae hatch as the temperature rises, and this disrupts the natural rhythm.
How do we fill the shelter?
Different insects have different needs, which is why we use various in the individual areas of the house Materials for the insect hotel.
- Bamboo tubes. Bamboo has solid partitions in the stem, so that we each get a sealed tube.
- Plant stemsl (abundant in winter and spring when dead perennials).
- Nesting woods
- Wood wool
- Snail shells
- Branches, twigs (for example elderberry, dog rose, cherry, willow)
Reeds, bamboo and stems are easy to process. The plant stems should be 2.5 mm to 1 cm in diameter and should be closed at the end. The mark should be removed with a stick or screwdriver.
We press the approximately 10 cm long stems into a tin can from which they do not fall out and fasten them.
For nesting woods, we use hardwood such as oak or beech and drill holes from 2.5 mm to 1 cm. This corresponds to the corridors that wild bees seek out in the dead wood. We drill from the long side, from which the beetles also eat themselves.
We never pierce the wood completely, a passage of about 10 cm is optimal, so we need thick pieces of wood. Drilling from diagonally above is optimal - then no water runs into it. The holes must not overlap.
Depending on the size of the holes, we attract different bees:
- The horned one Mason bee preferably 8 mm, the red 7 mm, the steel blue only 4-5 mm.
- The Scissor bees already make do with 3 mm.
- Mask bees and Wasps sometimes with 2.5 mm, but some species need 5 mm.
Ash, alder, beech and oak are suitable, well deposited and drilled transverse to the grain, so that no cracks occur.
Strand rabbets are particularly suitable in insect hotels. These have small holes in the right size for wild bees.
Rare wild bees breed in snail shells. For this we do not use the large houses of vineyard or agate snails, but the medium-sized houses of ribbon or snail snails.
Straw is suitable for earwigs and beetles. However, we create a straw box separately and at a distance from the beehives. Earworms eat the larvae of the bees, and their shelter should therefore be at a safe distance. You should set up catchy tunes near aphids, not near wild bee hives. You can fill old clay flower pots with straw and hang them upside down in the garden.
For a bee nesting aid made of bamboo, we saw bamboo cane into pieces eight centimeters long and remove split ends and cracks from the front opening. The length of the tube should be eight centimeters, if there are knots in the piece, let's drill them out. We glue the pieces to the back with a tile adhesive. To do this, we fill a two centimeter thick layer of the adhesive into the wooden house and press the bamboo pieces into it.
For a simple house we take four pieces of wood, each eight centimeters long, the width is based on the number of bamboo tubes. They should all fit in, but leave no gaps. We measure the back accordingly. Since the walls are not used for nesting, they only have to be so stable that the house can withstand wind and weather. Chipboard is enough.
In autumn we can cut a number of stems half a meter long, for example of elderberry, blackberry, butterfly lilac or dog rose, and dry them over the winter. In March we then bring them into the garden and attach them diagonally to trees, fences or walls. By the way: if you leave the stems of your perennials standing, you will achieve the same effect.
Role model nature
In nature, insects move into the upright stems of pithy plants. Therefore, you should put your stems upright instead of horizontally, as unfortunately in most commercial insect hotels.
The general rule: If you keep your garden "clinically" clean, ie tear out wild carrot and nettle on which caterpillars find their food, remove wildflowers as "weeds", and bring dead wood to the recycling center, an insect shelter is of no use.
Lay a dry stone wall, frame your beds with old branches and pieces of bark, leave a pile of stones, keep a wild corner where you do not mow or rake. Then you already have most of what distinguishes an insect hotel. So build this in addition to the structure of an insect-friendly garden - and not instead of this.
Nesting place for sand bees
For sand bees you need a sandy area. To do this, remove the soil to a depth of approx. 2 x 2 m and a depth of approx. 50 cm and then fill in humus, gravel and sand. The sand content should be 2/3. The floor should be loose and at the same time stable. If it is too dense, the bees will not be able to drill holes. If it is too loose, the gears collapse. You can prevent the sandy area from overgrowing by framing the area with boards. (Dr. Utz Anhalt)