I have several insect hotels in my garden, all of which I’ve bought rather than made, and all of which include hollow bamboo tubes. The idea is that the hotels provide habitats for different insects and the hollow tubes are there for bees to lay their eggs. These will be solitary bees, not honey bees which live in hives, and one such solitary bee is the Red Mason which is active and lays it’s eggs during April-May.
After a slow start to the year they’ve been super active in the garden this week and I’ve been watching their amazing work.
The bamboo tubes are quite long and the bees crawl inside to lay their eggs. The eggs will pupate into larva during the autumn, hibernating inside the hotel over Winter before finally the new bees emerge next spring.
Each bamboo tube contains several eggs and the construction inside is very intricate, as illustrated in the picture below.
The bee starts from the bottom of the tube by creating a little chamber and laying an egg in it. One egg per chamber. It then stuffs the chamber with lots of yellow pollen before closing it up and moving onto the next chamber. The inside of each tube in the bee hotel will look like this. The pollen is there as a food source for the larva when it pupates in autumn. This is how it can survive inside the bee hotel until next year.
Different bees use different materials and the red mason bee uses mud to create and seal the chambers, which in my garden it gathers from the ground under the insect hotel.
The other commodity our busy bees need is pollen, so for a successful red mason bee hotel we need the nesting tubes, mud and flowering plants. In my garden all are thankfully present and right now the main source of pollen is a wisteria plant which is only a couple of metres from the hotel.
In addition to being very beautiful the wisteria, glycine in French, is right now literally crawling with all sorts of pollinators, including I’m sure my nesting red masons.
Like all animals the bees time their egg laying activity based on the availability of food. Interestingly last year the mason bees had laid all the eggs and finished their work by the end of April. This year we had hard frosts and low temperatures through April delaying flowering, certainly my wisteria is later this year, and therefore the bees had to wait.
Right now they are constantly moving in and out of the tubes and currently two of them have been completed with the ends blocked.
The plug at the end of the tube is clearly mud, the tell-tale clue that the eggs have been laid by red mason bees. Other types of solitary bees might use the hotel. Leaf-cutter bees do exactly the same thing as mason bees but instead of mud they use, guess what, leaves, to make the chambers and block the end of the tube. These leaf-cutters are active slightly later in the year, June-July, when of course leaves are in greater abundance.
Last year in this particular hotel I had a dozen tubes completely blocked by the red masons, but I’m afraid life is not quite so straight forward for our bee eggs and larvae. They need to survive a whole year which is a bit of a challenge as they represent a nice food source, especially for birds.
Last Autumn the great tits and blue tits in my garden took quite an interest in the bee hotel and opened up all of the blocked tubes.
Obviously with their short beaks the birds cannot get to the end of the tube but I’m afraid if you are a larva in the first or second chamber your chances of survival until next spring are not high.
As so often in life it is best to be the first born and not the last, even for bees.