Some years ago in spring in the garden, i observed the activity of mason bees, making use of holes in the brick wall. I started reading about them and we bought a cheap insects hotel. The next season there was a lot of activity in it. Ofcourse this hotel had a short timespan so i decided to built my own more durable beeshotel.
Important to keep in mind is that if we make a hotel that can't survive winter, we don't help them, on the contrary we help them to extinct. so we shouldn't offer that cheap junk from China to our bees.
The first attempts were pieces of a square beech pole with holes drilled into it. I joined 3 pieces together and made a roof over them. This was a great success from the start, i love to observe the activities of these industrious creatures
An important thing to keep in mind is that the hotel is located outdoors and exposed to the elements. Sadly our climate is very wet in winter so I soon discovered that if the hotel is to survive the winter, it must be thoroughly protected from moisture. Otherwise the wood is going to rot and the bees nests will be destroyed. Bamboo tubes will split when they get wet.
The materials
THE HOTEL:
- wood or hpl (trespa)
- glue and screws
- roofcovering (aluminium, roofing felt,
NESTING MATERIALThe bees nest in tube shaped holes, to provide them we can use a.o.:
- wooden blocs where we drill holes in.
- pieces of bamboo tubes, reed, drinking straws, etc
- we can buy cardboard tubes
- stacked planklets with a slot milled into them.
It is obvious that, for the nests, we should't use materials that could harm the bees. Drinking straws should be save. I use "do&dry" clay as putty to close the tube ends. This material is allowed for children so also for the bees I guess.
THE ROOF
MOISTURE INGRESS
The major enemy of our hotel is moist. There are several places where there is a threat of moisture ingress. We can distinguish between:
- direct exposure to rain
- splashing water droplets
- dripping water blown in
- leakage of the roof
- water creeping on horizontal surfaces
This all can be prevented by the roof so this is the most important part of the hotel, without a good roof all the rest is pointless.
So what makes a good roof?
THE ROOFThe roof is ideally the only part that is directly exposed to rain. Its main properties are:
- absolutely water resistant
- large enough
- sloping
There are several ways to make the roof watertight. I like to make the roof out of mdf sheet that i soak with epoxy and cover with the aluminium of beverage cans.
It should be big enough to prevent rain against the sides and front of our object. In my experience the roof can't be large enough.
Water can creep on horizontal surfaces but will not creep up. So we avoid horizontal surfaces in the roof, it should always be sloping to lead the water downwards. On the edges of the roof we need ledges that water cannot creep over.
I make these ledges bij folding the aluminium lining like in the illustration. The water creeps to the lowest spot and will drip off from there. Preferable this is a spot where the wind cannot blow this drippingwater into the hotel.
OTHER MOISTURE THREATS
Most likely our hotel hangs on a wall so between the wall and hotel there will be a narrow space that is likely to always be humid. This means that it is very important that the back is also waterproof.
We also have to pay attention to eventual splashing water. Remove objects near the hotel from where the water can splash up into the hotel.
THE HOTEL
The hotel itself is in fact a sort of cupboard, covered with a roof. The sides and especially the back should be protected from moist. I paint them with uv resistant acrylic paint. In the cupboard we can make shelves where we can arrange our nesting material on. The shelves theirselves can also be drilled.
LOCATION
The best place to hang the hotel is where it gets several hours of sun. In my case it faces south-east, this is good because generally rain comes from the west.
As already explained, the back should be waterproof because most likely this is a weak spot. I usely mount spacers at the back to prevent contact with a wet wall. This way we have some ventilation.
NEST MATERIAL
The are many kinds of mason bees and they all have their own preference for the housing. If we have tubes between 3 and 9mm we cover the most important housing needs. The tubes should not be too long <16cm, surplus is not used). They should be smooth inside, free from splinters where the bees scratch their wings on. Bamboo tubes should be intact, split tubes will not be inhabited. If we drill in wood, we need to use hard wood because pine will splinter too much.
If we drill the wood across the grain we get the best holes. Along the grain could mean that the wood splits too easy.
Furthermore anything with a hole in it will be used, like brick, plaster brick, cell concrete, use your imagination.
The mean target is to help the mason bees but the are more insects that we can help. For instance ladybugs we can provide with a dry shelter, these are useful lice removers. This could be a pot with crevice-shaped openings. These can be real works of art that looks great in our hotel.
MAINTENANCE
PREPARING FOR WINTER
In fact we don't have to worry much about out hotel. If we are sure it is protected against rain we can leave it safely outside in winter. However exceptionnal weatherconditions like the traditional autumnstorms could threaten the hotel.
To minimmize the risks I evacuate the nesting material when the season is over. I put all the housings in a cardboard box and put it in a dry place. By the end of february I put them back in the hotels.
Another measure could be to mount a plastic curtain at the front that keeps rain and wind out (please note: ventilation is important). It is even possible to move the whole hotel to a cool dry place like the shed or under a canopy.
NESTING MATERIAL
At the end of the season we can inspect out tubes. We can clean the ones that are not occupied (they have a small hole through which the last generation emerged) so that they can be used again. We remove the splitted bamboo tubes.
If we have demountable pipes we can screw them apart and collect the cocoons to hibernate them in the refrigerator. However you should know what you are doing then, please google for more info on this subject.
THE GUESTS
The guests are mainly mason bees, they don’t live in colonies, but instead, each female builds her own nest. This is preferably a tube (3 to 9mm) in which cells are built where the offspring can grow up.
If we have a well made hotel, the guests will find it soon enough. It is amazing how quick these bees find suitable nesting opportunities.
Where i live (in the netherlands) the most common species in the early spring are the red mason bee (Osmia bicornis), the horn-faced mason bee (Osmia cornifrons), the blue mason bee (Osmia caerulensens). They belong to the biggest species and nest in pipes 6 to 9mm.
Later in the season we will see the thinner tubes are occupied by smaller species.
OTHER INSECTS
Apart from our bees there are other beneficial insects that we can help by providing them places to hibernate, save from predators and rain.
To mention one, the ladybug. We know they like to crawl in small crevices were the can't be reached by birds and other predators. With some imagination we can make really nice artistic shelters for these insects. I made some objects where i can put some dry plantmaterial in. With small crevice-shaped openings. Important is that no water can run in so i made the entrances with an ascending slope.
As far as these objects can withstand the weather we can leave them outside, otherwise we can place them in the hotel where it is dry.
