What are Solitary Bees?
As well as Bumblebees and Honey bees, there are over 240 species of wild bees in the UK that make individual nest cells for their larvae. Most species nest in small tunnels or holes in the ground or in sandy banks, piles of sand, crumbling mortar, or sparse starved lawns. You can leave areas of bare soil or gravel in your garden for these.
Some wasps live in dead plants or in tunnels made by beetles. They eat small insects and are harmless to humans. Some of the more distinctive species of wasps that are common in gardens are described in a fact sheet about solitary bees and gardens.
Although they are known as solitary bees, some species willroup their nest cells together in aggregations, and a few have evolvedocial behavior rather like bumblebees. Many solitary bees areery small and you may not have realized they are bees. Allollect nectar and pollen from flowers, except the so-calleduckoo’ species that lay their eggs in the nest cells ofther species.
Solitary bees are not aggressive and will only sting humans if they feel threatened. These bees do not have painful stings like honeybees, so if they do sting a person, it will not be painful. Solitary bees do not live in hives or make honey like honeybees do.
If you find a bee’s nest, please do not disturb it. The bees are very loyal to their nest sites and may have been living there for many decades. They are part of the local biodiversity and should be respected.
Some species of bees that are commonly seen in gardens, like Red Mason and Leafcutter Bees, build their nests in tubes or tunnels. They’re very helpful for pollinating fruit crops. Gardeners can encourage these bees by providing them with artificial nest sites, such as drilling holes in dry logs or blocks of wood.
These bee houses are more commonly referred to as ‘trap nests’, or, in America, ‘bee condos’. While it has become trendy to call them ‘bee hotels’, I believe this is misleading, as they are not simply temporary housing like hotel rooms; they are the bee’s permanent home for eleven months of its short life, during which it develops from an egg to a larva, then a dormant pupa, and finally an adult.
Buying Bee Houses (‘Bee Hotels’)
Although bee houses only attract a small number of bee species, they are still interesting and educational to watch.
In the light of public concern about sudden bee declines as reported in the media, (a story in fact originating from honey bee declines in North America), many horticultural suppliers have jumped onto a lucrative bandwagon and a number of commercially-made wooden bee houses are now available. Most of them are expensive, and sadly many of them are inadequate for a number of possible reasons:
- they offer insufficient protection from wet weather
- the holes are too large, because they are made abroad to cater to species that do not live in the UK
- tubes have splinters inside
- tubes have no solid back wall and are simply open-ended wind tunnels
- they contain glass or plastic tubes which cause condensation and fungus molds
Manufacturers do not mention that Red Mason Bees and Leafcutter Bees, which they aim to attract, are not found in some parts of Britain and Ireland, so beware of wasting your money! The only commercially-made bee houses that I would suggest trying out are those from Nurturing Nature. Alternatively, follow my instructions below and make your own inexpensive bee houses.
Bee Houses Must be Managed!
You should not simply site your bee house and forget it, as this may result in unoccupied cells, winter mortality of larvae due to fungus molds, and the spread of parasites.
Ideally, you need a system where you can:
- Identify at the end of the summer any cells that remain in a walled-up condition from the previous year because no young bees emerged. The contents of these cells will be dead and should be removed and destroyed.
- Identify any cells which have been taken over by the fly Cacoxenus indigator, whose larvae eat the pollen store and bee larvae. The contents of these cells should be removed and destroyed before the adult flies emerge.
- Replace drilled blocks with brand new ones every two years. This is done in the summer after the young bees have emerged. It will help to prevent the build-up of fungus molds, mites, and other pests and parasites.
What is a Bee House?
Bee houses provide a place for solitary bees to rest and nest, just like birdhouses. Mason, leafcutter, and mining bees are all types of solitary bees that would use a bee house. However, honeybees live in colonies and not alone, so they would not use a bee house.
Most mason bee houses look like little wooden houses that are filled with nesting tubes. The tubes are there to provide the bees with a place to hibernate and nest.
As gardeners, we help protect bees by adding a bee house. This way they have a safe space away from our garden work and visitors.
Building a bee house allows you to welcome bees into your space and show appreciation for their hard work. I also enjoy using mine as a teaching opportunity whenever someone is curious about what it is.
How to Make a Bee House
If you want to build a bee house, there are a few different ways you can go about it. However, all bee houses follow the same general rules. Here is all the information you need to know about creating a bee house that is uniquely your own.
A container is something that can hold things, like a coffee can or milk carton. Sometimes they are permanent structures, like ones made out of wood.
While a big bee house may look impressive, it may be too difficult to take care of for a beginner who would then have to deal with too many bees.
The size of the house should also be appropriate for the amount of food available. For example, if you have a lot of flowers, you can support a bee population.
The container should be open at the front and closed at the back. Ideally, it should have an overhang to protect it from rain and other external factors.
Apply a waterproof coating to the structure to keep moisture out. You can also make your boxes more visible in your garden by painting them.
Since bees use a variety of materials to build their houses, it is a good idea to provide a range of materials and sizes of tubes.
There are a few different ways that you can make tubes for your insects. You can either use rolled up paper or cardboard, or fill the house with paper straws and hollow reeds. Some people also use bamboo, but it can retain moisture and is more likely to develop pests and fungus. I have used bamboo reeds in the past and had no problems, but you need to keep a careful eye on them.
Make your own tubes by taking some thick paper and rolling it around a dowel. Tape the paper and gently slide the dowel out. Bend one end of the tube and tape it shut so no light passes through. Tubes should be a minimum of 6 inches deep.
Addition: If possible, put the container on its side so that the tubes get more sunlight. Tape your bundle of tubes together and insert it into the container so that the overhang protects the tubes but also so that they still receive direct sunlight. If possible, put the container on its side so that the tubes get more sunlight.
Nesting blocks are another option you can use. This involves drilling holes of various diameters into small pieces of wood to accommodate different types and sizes of bees 1/16-5/8” in size.
Untreated wood should be used to make bee houses. Pine, spruce, and oak are some good bee-friendly options.
Annual Management of Bee Houses
The following techniques may help to prevent the build-up of parasites such as the Cacoxenus fly.
Dealing with Cacoxenus indigator
This is a very small fly with red eyes. It is a cleptoparasite that affects Red Mason Bees. The larvae of these flies eat the pollen store and the young bee larva in the Red Mason Bee’s cells. The fly larvae then bite small holes in the mud walls of the cells, before pupating. They remain as pupae throughout the winter and the adult flies emerge in spring, using the small holes in the mud walls to escape. In late summer or autumn, you should examine all the tubes that have been walled up with mud during the summer and identify any in which there is now a small hole. These have been taken over by the fly, and these tubes or tunnels should be cleaned out and the contents destroyed.
If you suspect that the bee larvae in your hive have died, there are some things you can do to check. One suggested method is to look for capped brood cells that are sunken in and have cracked caps. If you find brood cells like this, it’s a sign that the larvae inside have died.
If moisture gets into a cell, the pollen store can go moldy or the bee larvae or pupae can succumb to fungal diseases. Also, bee larvae can be killed by the Monodontomerus wasp or by invasions of pollen mites that eat the pollen store, so the bee larvae starve. During winter, after removing the contents of any tunnels that have fallen prey to the Cacoxenus fly, mark all sealed tunnels with a colored marker pen. This won’t harm the emerging bees next season as they don’t ingest any of the mud wall of each cell; they simply break it up to get out. At the end of next season (i.e. next September or October), any tunnels that still have the colored mark represent those from the previous year in which the bee larvae died and didn’t emerge. These should be cleaned out, or in the case of bamboo or cardboard tubes, removed and destroyed.
If your beehive has old, worn-out bee blocks, logs, or dry stems, you’ll need to replace them with new ones. Here’s how to do it: 1. Lift the top off of the hive and set it aside. 2. Remove the old bee blocks, logs, or dry stems and set them aside. 3. Place the new bee blocks, logs, or dry stems in the hive. 4. Put the top back on the hive. To replace bee blocks, logs, or dry stems in your hive, first lift the top off and set it aside. Then remove the old bee blocks, logs, or dry stems and set them aside. Next, place the new bee blocks, logs, or dry stems in the hive. Finally, put the top back on the hive.
You should replace blocks every two years with newer ones. Proceed as follows:
To prepare for the bee emergence season, get new tubes, drilled blocks, or drilled logs ready. Get a thick black plastic bucket and cut a triangular notch in the lip. You can also use any other large, opaque plastic container or an old wooden box. Cardboard boxes can also be used but as they are not waterproof, they have to be protected from rain in some way. Just before the first adults are due to emerge, move the occupied tubes or blocks from your bee house and place them on the dry ground beneath the inverted bucket or box, near your bee house. When the bees emerge from the tubes, they will fly towards the light and leave the upturned bucket or box through the small gap where you cut the notch. Place the new tubes or blocks in your bee house and the young bees will occupy those.Leafcutter bees emerge, on average, two months after Mason bees. Be sure to check for ants, earwigs, or slugs periodically, as they can become a problem. Once all the Leafcutter bees have emerged from their old blocks or tubes, remove and destroy them.
The same technique can be used to replace dried stems that have been occupied by solitary bee nests. Cut the stem at an angle above the brood cells and peel back the outer layer of the stem. The cells can then be gently transferred to a prepared nesting block.
The procedures outlined in the text need some care and dedication to be successful, forgetting about the bee house will not help the bees.
FAQs About Bee Houses
What Are Wild Bees vs Bought Bees?
Companies have started selling bees to help with commercial pollination because they are such good pollinators. You can actually buy the cocoons of these bees to put in your yard.
It is more beneficial to look after the current bee population rather than introduce new ones that have been purchased. This will help the health of the environment and native species as a whole.
Do Bee Houses Really Work?
You should maintain bee houses in urban settings, as this provides the best possible nesting habitat for solitary bees. If you do not take care of bee houses, they can become homes for pests, which is bad for the bees.
If you see that the tubes are slowly filling up with mulch and leaf debris, that means there are bee larvae inside.
It is better to make your own bee house than to buy a commercial one. The materials used in most commercial bee houses are not suitable for bees and can be harmful to them.