How to make an insect hotel?

Today, we can only note that the balance of our relations with insects is difficult to find, between nuisance and cooperation. By making an insect hotel, you give them a helping hand to get through the difficult winter period and shelter their eggs. To carry out such a project, you must first take an interest in the species to welcome because not all of them have the same lifestyles and therefore the same needs. We guide you.

What is the point of an insect hotel?

An insect hotel aims to provide shelter for insects to promote their reproduction. They of course find natural shelters in your garden. It can be a pile of stones, dead wood, tree bark, dead stumps, etc. But not all of these materials are necessarily present in your garden or nearby. This is why such a shelter helps to promote local biodiversity by promoting the balance of the food chain.

It is quite relevant to want to build one yourself because it is not a difficult project to achieve and it allows to reuse scraps of various materials. It is above all an approach that invites you to learn more about insects. Indeed, the hotel does not aim to help just any insects, but those that are useful, those that we call auxiliaries of our gardens, that is to say those that fight against insects clearly identified as parasites or harmful: it is an exchange of good practices in short!

The actual manufacture of the insect hotel

1 – Start by identifying the insects you want to promote (see our list below).

2 – List the materials you need:

  • logs and other pieces of dry (about a year old) and rather hard wood, such as oak, beech, ash, apple tree, hornbeam, chestnut, acacia.

To hole logs, bricks or concrete blocks, vary the diameters (between 2 and 14 mm) and the depth (between 8 and 10 cm). If the supports are drilled right through, they will not be occupied. It is absolutely necessary to leave an insulating bottom. The holes are spaced at least 2 cm apart and arranged in a row.

  • bricks and blocks of expanded concrete.
  • straw or hay.
  • marrow stems (bramble, rose bush, raspberry, elderberry, buddleia, Jerusalem artichoke, weigelia, hydrangea…).
  • Hollow stems (reed, bamboo, Provence cane, forsythia, deutzia and even straws used for drinking) with a length of between 10 and 20 cm and diameters varying between 2 and 12 mm.

They must be plugged at one of their ends, either by natural knots, or by clay or loam. Make sure the plugging is thick enough so as not to cause slits that run right through and cause drafts.

3 – Draw a diagram of your future insect hotel which fixes the general structure (do not see too big for the first time) and the interior organization: “rooms” and fittings.

Once the plan is complete, calculate your wood requirement. Choose a durable wood species such as larch or douglas. Ideally, the depth of your hotel is 17.5 cm and the boards used are 3 cm thick.

4 – Build the hotel. The assemblies will be made with stainless steel or brass screws. The tightness of the whole is an essential factor for the success of the project. The roof must protect the whole from rain and runoff. You are free to choose its shape (generally two-sided) and the material of your choice, depending on what you have at your disposal: slates, tiles, shingle, aluminum …

5 – Once the hotel is finished, brush all the exteriors with linseed oil.

6 – Install the hotel (see indications below)

A hotel, yes, but for which insects?

This list is far from being exhaustive. You can complete it at your convenience. The upstream documentation concerning the insects to be accommodated is an essential and important part of the insect hotel project.

The lacewing is a small green insect with translucent wings. Its larvae feed on aphids (to the point of being nicknamed “aphid lion”), spider mites, whiteflies and thrips. Adult, it is a pollinating insect which feeds on the nectar of flowers. Lacewings lay their eggs as early as February. They take up residence in the marrow of elderberry stems, in pierced logs, in blocks filled with crumpled paper, dead leaves and dried grass.

Earwigs or earwigs also delight in aphids, but also psyllids, mites, slug eggs and very ripe fruits. These animals fear light and are fond of straw and rough terracotta flowerpots.

The osmias retorts are the best known of the solitary wild bees. They are pollinating insects that can be confused with bumblebees as their body is fluffy. They are also with him one of the first insects to appear in the garden. Their reproduction begins in March. And the females seek cylindrical and deep shelters which they line with earth and at the bottom of which they place a reserve of nectar and pollen to feed their future larvae.

The hotel will also be able to accommodate other kinds of bees: carpenters (which dig dead wood), rubicoles (which settle in the pith stems), tapestry-makers (which nest in pre-perforated dry wood ), and Masons (who use cells lined with mud).

Ladybugs are well known to delight in aphids. For shelter, they look for piles of dead leaves, hollow stems, holes that can be drilled in brick or wood, or even gaps created by the superposition of wooden planks in mille-feuille, spaced apart by some small gravel.

The ground beetles are beetles often confused with beetles. Their larvae feed on hazelnuts and codling moth caterpillars. They appreciate old stumps and branches.

An insect hotel: when and where?

The ideal orientation is South or South-East, especially at the beginning of the day, back to the prevailing winds, raised by at least 30 cm so that the whole is preserved from soil moisture. The location chosen should be quiet, away from comings and goings, and near a flower bed so that the insects have easy access to food. Installing the shelter before the end of winter maximizes your chances of seeing it used as early as March.

However, the inhabitants will not necessarily be there. Observations show that of all the insects listed above, osmias are the quickest to occupy the places intended for them. On the other hand, the others, and in particular ladybirds and lacewings, are more reluctant to settle, and their homes may remain unoccupied. It is also possible that insects will be more inclined to occupy an older hotel, which has been outside enough time to blend in with the natural surroundings.