October 25, 2023

A deep dive into the world of wild bees and how to build your very own bee hotel 🐝

An interview with Ramona Lichtenthäler, a Planet Wild community member, who shares her knowledge about wild bees and tips on creating your own wild bee hotel

Bees are incredibly important to all life on Earth - they play a key role in maintaining biodiversity through pollination. Unfortunately, many bee species are critically endangered. Is there anything we can do about it?

One of the Planet Wild community members, Ramona Lichtenthäler, has a few practical tips for ways to protect this important insect.

PW: Ramona, you mentioned that you are passionate about wild bees and have done a few things to help them in your free time. Can you tell us more about it?

Ramona: Certainly! I can talk about wild bees for hours, so I hope you have time!

In Germany, we're home to around 580 species of wild bees. While most people are familiar with bumblebees, there are countless other lesser-known species. They come in different sizes, colors, and have diverse lifestyles. However, the sad reality is that we're losing them at an alarming rate – about half of them are now on the Red List of threatened species.

This decline isn’t just a small concern - it is a direct threat to the very foundations of our food production and biodiversity. It's like a Jenga tower: You can remove numerous blocks, but once you pull out one too many, everything collapses. In Europe, we've already lost 75% of our once-abundant insects in the last 30 to 40 years, and they sit at the base of the food chain. So, I felt the need to start doing something.

To take practical action, I started installing insect hotels in my garden. At that time, I was a novice in the world of insect hotels, and I didn't fully understand the specific needs of wild bees. So, I simply visited a local supplies store, a Baumarkt, and purchased one. Now I really wonder who designed most of these commercially available insect hotels because most of them aren't suitable for wild bees.

‍PW: Intriguing! Could you elaborate on what makes an insect hotel ideal for wild bees?

Ramona: With pleasure! But before we get there, let’s first talk about the ways and reasons the wild bees would normally use an insect hotel.

Why would wild bees use an insect hotel

The majority of wild bees in Germany are solitary bees, meaning they do not live in colonies, as we know it from honey bees, for example. Instead, each female bee builds her own nest for procreating.
Solitary wild bees would not build their nest just anywhere. They require nesting holes - these can naturally occur or be made in hollow sticks, dead trees, or even in the ground.
Solitary wild bees have a very distinctive nesting behavior: They enter a hole, provision it with food, lay an egg, and seal the hole behind the egg. They repeat this process for subsequent eggs, creating a series of cells stacked end to end within the stem.
What is more: When a bee lays eggs, she starts with fertilized ones that will become female bees. As she works her way toward the nest entrance, she lays unfertilized eggs, which will become males. By placing the female eggs deeper in the stem, she protects them from predators, as the males act as a shield. Male bees develop quicker and emerge before the females, waiting for them, ready to mate.

A bee hotel - sometimes also used by wasps

Now, knowing all that, let’s come back to what would make a wild bee hotel an attractive residence.

What would make a wild bee hotel an attractive residence

The size of the holes is crucial. The ideal diameter falls within the range of 2 to 12 millimeters, closely matching the typical size of wild bees. A tiny bee doesn't want to spend materials and energy to fill a hole that's disproportionately large. Also, larger holes can be more easily accessed by potential predators.
The length of the nesting holes. To ensure a balanced gender ratio, the nesting holes need to be sufficiently long, at least 8 centimeters.
A mesh should be placed at the entrance to the insect hotel to deter birds from feasting on the bee eggs. The mesh should be securely fixed to prevent birds from pulling out the sticks.
The hotel should be located in a sunny location and have some sort of rain protection, to provide dry and warm environments.
Hotels also serve as winter habitats. If you notice closed stem cells in autumn, it often means new bees will hatch in the spring. Therefore, it's crucial to leave the hotels outdoors, as the new bees might otherwise hatch too early and die because of lack of available food.

‍PW: Nature is truly fascinating! Thanks for breaking this down for us. How can we ensure that bees actually start using newly installed hotels? It could be really frustrating if your efforts go unnoticed.

Ramona: Right. To entice them for a first visit and encourage them to stay, you need to ensure there's an abundance of water and nourishment in the vicinity. You can provide a simple bowl you regularly refill or, if you have a garden, a small pond. It's essential to add something in the center of these water features, so if a bee takes an accidental dip, it can easily find its way out.

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When it comes to nourishment, nothing beats the charm of local flowers. Ideally, you'd want a selection of local flowers that bloom from late winter through the end of autumn. So, when the first eggs hatch in February-March, they already have some nourishment. In Germany, these would be wild crocus and tulips, for example.

Flowers that come from other countries will only help the generalists, like honeybees and bumblebees. But many wild bees are specialists - they evolve together with the local wild flowers, so their bloom times coincide with the bees' search for food. It's a beautiful symbiotic relationship. Many commercially bred varieties may look lovely, but they lack nectar and pollen, the two essential food sources for insects.

PW: When is the best time of the year to install a new bee hotel?

Ramona: You can install a bee hotel at any time, but late winter, around February, is best. Right now, in October, most wild bees have already perished. They have a short lifespan, usually only 2–3 weeks, focused on procreation. So, by October, their job is done. Now is the ideal time to start learning about wild bees; read books, watch videos, and prepare for the next season.

If you want to construct your own hotel, you need to know that there are at least three different types of bee hotels that are suitable for solitary wild bees.

Classic insect hotel

If you want to make a house-like insect hotel, you can purchase reed stems or bamboo stems for example (just make sure they aren't too thick).

You can then place these sticks inside a regular insect hotel or utilize an empty coffee tin by filling it with as many sticks as possible.

You’ll find everything you need on the Internet. Lots of people have specialized in selling suitable materials. Just look for nesting tubes for bees (Niströhre in German).

Vertical mini hotels

Many wild solitary bees prefer vertical homes! So, to accommodate them, you can simply take a branch with a soft inside, like raspberry or blackberry, tie it with a wire to a harder stick that won't rot when touching the ground, and secure it in the soil.

Wild bees will dig holes inside the softer branches and lay their eggs there. A few of these vertical homes can already make a significant impact. Position them in a sunny, dry location with an overhead roof for ideal conditions.

Sand hotels

These hotels cater for ground-nesting solitary bees, who normally excavate nests in sandy soil.

The sand pile should be at least 50 centimeters deep, allowing bees to create nest chambers for their larvae's development. Ideally, make the sand above ground sloped so rainwater can run off without damaging the structure.

So, dig a hole in a sunny spot, fill it with sand, drill a few holes to invite the bees, and ensure you use builder's sand with clay - otherwise the holes won’t hold.

Also, I would suggest placing some thorny branches on top, so that local cats don’t claim it as a litter box.

Ready-made hotels

For those who prefer ready-made options, you can buy a good insect hotel from specialized dealers, like this one. It’s important that the hotel features a variety of hole sizes, ranging from 2 to 12 millimeters, have the right length and have a small roof to offer protection from the rain.

‍PW: Wow, it’s a whole new world that you have just described. Are there other ways that people can contribute if they love nature, but don't have either a balcony or a garden. Is there anything else they can do?

Ramona: Yes, absolutely!

How to contribute if you don't have a garden or a balcony

You can still make a significant impact by simply scattering the seeds of local wild flowers in your surroundings. It's an easy and effective way to support bees and other essential insects.
Another way to contribute is through the use of apps that help identify local plants and insects, and simultaneously use this data in the analysis of local wildlife. By using specific apps, like Obsidentify and enabling geotagging on your smartphone, you can provide valuable data that assists scientists in monitoring the distribution of insects and plants. Just go around making pictures of insects and plants, and expand the knowledge about insects and the wildlife that lives around you.

PW: Thanks so much for taking the time to share your passion with our community!!

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If you would you like to join our community of like-minded individuals, you can use Ramona's invite link (or enter her code manually: 4443XR). By signing up this way, we will plant 3 trees for you and an additional 3 trees for Ramona during our upcoming mission in Senegal.