I posted my first Mason bee update on 25 March and I was really satisfied that I had attracted Osmia to my new Mason bee houses and I hoped to gather a bit of data on what might be suitable spots to situate Mason bee houses and what sized holes they preferred.
Firstly, no surprises, it looks like in France, at least, the bees prefer a sunny position. Out of the first three new hotels that were put up, it was the one on the wall in the front garden, with the morning sun, that attracted the most bees.
The bamboo canes had been chosen to give a diameter of 6mm to 1cm. I think the smaller diameter was favoured but my task was complicated as a potter wasp decided to use the hotel too. The potter wasp is responsible for the filling of the larger hole in the picture and the open holes are where the wasps have already vacated. I presume some of the other holes may hold wasp larvae.
The Bee hotel in the plum tree that received only dappled sunlight through its branches has Osmia and some other insects nesting but like the one under the willow at the bottom of the garden received fewer Osmia than the sunny hotel.
The bees arrive!
Keeping on track, not only did my original hanging house hatch out last year’s Osmia cornuta and have some more bamboo canes re-occupied but the new neighbouring one on the wall was even better received.
The O. cornuta preferred the new nest on the wall either because it was sunnier or because it was fixed securely to the wall rather than swinging on the branch of the lilac.
And then a second variety!
I had first seen the O. cornuta males around the old nest box at the beginning of March but in April I spotted another species of male Osmia in the garden.
The Osmia rufa are not as brightly coloured as the O.cornuta and hatch out and fly later. I had never noticed them in the garden before.
Both the O. rufa and the O.cornuta have curious prongs on their heads just under their antenna. The prongs are used to tamp in the mud they bring to seal their nest.
With two species of Osmia nesting in the hotels my husband became concerned that they would run out of holes or feel overcrowded so he hastily built a fourth hotel to go on an outbuilding wall that receives the sun all day long.
The third Osmia provides lots of entertainment in the summertime!
The Osmia leiana were the next arrivals in May and stayed around well into July. These little bees really put everything into building their nests. Gradually they fill the holes, cell by cell, and you can get a better look at all the action as they complete the last one or two compartments. I had now three species of Osmia nesting!
The Osmia leiana is not so colourful as the other two Osmia but nested for a longer period and the females even slept overnight in the bamboo of the hotel.
All the Osmia bees have strong mandibles to help them in building their nests. The O. leiana were prolific nesters and nested in all the bee hotels, even building a few nests in the hotels in the shade under the trees.
Then there is the Anthophora!
I have Anthophora plumipes nesting in the stone walls of the house and in May they were feeding on the blue Cerinthe in the front garden. I think this is a female of the light form that I have here starting off her nest in the holes of the trunk section of the bee hotel in the front garden.
The Anthophora have nested in the bored wooden holes in the cut tree trunks of the bee hotel on the out building too. They nest deep inside the holes but their presence is noticeable as they leave “paths” of sawdust on the bottom of the holes. They do this in the holes in the house walls but the “paths” in this case are like fine sand produced as they excavate their nests in the soft limestone.
And the Anthidium!
Another bee that nests in the bee hotels is the Anthidium. It is called the cotton bee in French for obvious reasons. She gathers the soft hairs from plants such as Stachys and brings them to the bamboo canes to make her nest.
Frequently the nest is made deep into the hole and the cotton does not protrude so it is easy to miss their nests. It is really amazing to see the quality and quantity of cotton that this bee produces. I have a great attraction for this lovely bee.
Different Megachiles arrive!
I had noticed suspicious pieces of leaves missing from plants in the garden during the summer and I had suspected leaf cutting bees but I had never caught any “in the act” so I could not be sure. So I was ecstatic when at the end of August I found them nesting in the sunny hotel on the outbuilding. They were so engaged in their task that they did not object to being watched. I found their determination and hard work fascinating to watch.
Some leaf cutting bees also nested in the hotel in the front garden but they were not early risers and I used to enjoy watching them wake up. This little bee had been so busy that she fell asleep on her back with a piece of leaf for a blanket. I took the photo at 9.49 a.m. and she was awake shortly after.
At the beginning of September one of the leaf cutting bees used rose petals to make her nest. I did not see her but the end result was beautiful. I think they are most likely to be Megachile centuncularis.
I am puzzled by this hole as it is shiny (I couldn’t manage to get a photograph to show the shine). Who has filled this hole? Is it another species of bee such as Colletes which line their underground nest with a cellophane? Or is it some other insect?
The other puzzle is how many different types of bees are nesting in the bee hotels? I have photographed six different species of solitary bees in this post. In addition, I think there is more than one species of Anthophora in the hotels and what about the ones I’ve missed?
I am always on the look out for parasites and predators, which are numerous.
I was concerned when I saw this on the nests at the end of September.
This wasp came around at the end of September and seeing her putting her long tail into the bamboos I worried that she had been laying eggs in the bees nests. Apparently she prefers to parasitise wood boring insects but the larvae of the potter wasp which also used the bee hotel could also be a target.
And then there’s our lizards!
The lizards can be a bit of a pain as they insist on squeezing in between the bamboo and sometimes they will dislodge one causing it to fall. I replace it but I think a winter job will be to put a backing behind the bamboo to keep out the lizards. I comfort myself thinking that they will eat any little flies that might be lurking around.
I’m just not sure how vigilant my lizard guardians are but I can always hope.