What are Solitary Bees ?
There are over 240 species of wild bees in the UK, most of which nest in small tunnels or holes in the ground, or in sandy banks, piles of sand, or crumbling mortar or sparse starved lawns. You can support them by leaving areas of bare soil or gravel in your garden.
Some species of small, solitary wasps build their nests by reusing hollow stems from dead plants or tunnels that have been bored into dead wood by beetles. These wasps are harmless to humans, but they are predators of small insects. Some of the more distinctive wasps that are common in gardens are described in my fact sheet about solitary bees and gardens.
Some species of solitary bees will group their nest cells together in aggregations, while a few have evolved social behaviour similar to that of bumblebees. Many solitary bees are very small, and you may not have realized they are bees. All collect nectar and pollen from flowers, with the exception of the so-called ‘cuckoo’ species that lay their eggs in the nest cells of other species.
There are approximately 200 species of solitary bees in North America. Approximately 200 species of bees that live alone exist in North America and are mostly harmless to humans. They will only sting humans if they feel threatened or are squished, and their sting is not as painful as that of a honeybee. These bees also do not produce honey or build hives.
Leave hornets’ nests alone if you come across them, as they have likely been living there for many years. They are part of the local biodiversity and should be cherished.
Many different kinds of bees commonly found in gardens, like the Red Mason and Leafcutter bees, build their nests in tubes or tunnels. They’re very helpful in pollinating fruit crops. Gardeners can encourage these bees by providing them with artificial nest sites, like drilling holes in dry logs or blocks of wood.
These bee houses are also called ‘trap nests’, or in America, ‘bee condos’. It has become fashionable to call them ‘bee hotels’, but this is misleading, as they are not short-term accommodation like a hotel room. They are the bee’s permanent home for eleven months of its short life as it develops from an egg through a larval stage, then as a dormant pupa, and finally emerges as an adult.
Buying Bee Houses (‘Bee Hotels’)
Although bee houses only provide nesting sites for a small number of bee species, it is still interesting and educational to watch them using them.
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 on to 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 for 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 moulds
Manufacturers of bee houses do not give adequate instructions for long-term care, or mention that the species of bees they want to attract, Red Mason Bees and Leafcutter Bees, are not found in some parts of Britain and Ireland. It would be a waste of money to buy one of these houses, so either find one from Nurturing Nature, or follow the simple instructions below to make your own.
Instructions for a Simple DIY Bee House
Home-made bee houses can be made fairly cheaply using re-cycled or waste wood and logs. All you need is a wooden box, open on one side, with a sloping roof to deflect rain. The box should be a minimum of 20cm (8ins) deep, and needs an overhang at the top to keep rain off. The bee house in the picture is 20cm deep, 30cm (12ins) high at the front and 30cm wide, made out of untreated European spruce. It has a sloping, slightly overhanging roof to deflect rain.
If the bee house is to be free standing, fixed to a pole, you must give it a back, to give protection from rain and wind.
The size of the bee house does not matter, as long as it is large enough for the bees. It is possible to make a extremely large, free-standing bee house, but it is not recommended. Doing this could invite parasites and diseases, as it would not be easy to manage. Smaller bee houses are easier to take care of.
A container can be anything that can hold something else. This can be anything from a coffee can to a milk carton. Often, containers are permanent structures made out of wood.
While it may look cool, a huge bee house may be too difficult to maintain for a beginner.
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 the rain and other external elements.
To keep your structure from getting wet, you can paint it with a waterproof coating. You can also make it more fun and personal by painting it with bright colors.
Since bees use different materials to build their nests, it is a good idea to provide a range of materials and sizes of tubes for bee houses.
You can make your tubes out of rolled-up paper or cardboard, fill the house with paper straws and hollow reeds, or use bamboo. Some people worry that bamboo will retain moisture and cause pests and fungus, but I have used it in the past with no problems. Just be careful to keep an eye on it.
To make your own tubes, take some thick paper (such as packing paper) and roll 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.
Tie your bundle together with tape and insert it into the container. Pack the tubes tightly together so that they fill the container completely. Insert them so that the overhang protects the tubes but also so that they will still receive direct sunlight.
You can also use nesting blocks which involve drilling holes into small pieces of wood. The holes should have different diameters to accommodate the different types and sizes of bees. They should be 1/16-5/8” in diameter.
Use only untreated wood to make your bee house, such as pine, spruce, or oak.
How to Maintain a Bee House
The bee house you build needs to be maintained or it can be deadly for the bees.
Some predators affect solitary bees by stealing the pollen that the females leave behind for their offspring, which leaves none for the larvae. This includes pollen mites, carpet beetles, and the Houdini fly.
Without proper management, bee houses can become overrun by parasites that feast on the cocoons of the bees, including parasitic wasps and chalkbrood fungus.
The cavities that bees live in are usually spread out in nature, but in human-made homes, there are a lot more bees living together. This makes them more likely to get mites and other pests, so it’s important for people to take care of them instead of just leaving them alone as they would in the wild.
The materials should be cleaned out once a year, preferably between September and November. This is when the bees will be fully formed.
Once the bees have finished spinning their cocoons, you will remove the tubes and inspect them for parasites. This process is called harvesting the cocoons. You can learn how to properly harvest and store bees at the David Suzuki Foundation.
Throw away any used tubes and clean the entire machine using soap and water. Soak and scrub any nesting blocks you intend to reuse.
The best time to remove a beehive from your house is after the last frost, in February or March. It’s best to put it back in the same spot every year, as some bees like to return to their old nesting spot. If any of the tubes are discarded, replace them with new ones.
Place cocoons in a protected, sunny spot close to your house. Mason bees come out in the spring, and leaf cutter bees in June.
Be sure to check on your house every few weeks to ensure that everything is running smoothly. You can also keep birds such as woodpeckers and blue jays out of your house by covering the exterior with metal netting. However, do not cover the nesting holes as this will prevent bees from entering.
Some people on the continent build special bee walls out of soft mortar for Mining bees, but the author has had no success with this. They recommend keeping some sunny patches in your garden clear of vegetation and mulch to help them out. Stacks of upturned turfs in sunny places are sometimes colonised by mining bees. You can also try creating mounds or slopes of sand or sandy soil in a sunny place specifically for Mining Bees. You will need to hand-weed the patches occasionally to keep them clear of vegetation, and you may need to put up a fence to keep animals from disturbing them.