All through last winter, one shelf of our fridge was taken up with Red Mason Bee cocoons. They were being stored at the right temperature and humidity to keep them safe and healthy ready for their triumphant emergence in the spring.
In late March we put mixed-sex batches (the male cocoons are smaller) out into the release box and waited for them to hatch and fly away:
The idea of the several small batches is that not all your eggs are then in one basket should an unexpected patch of bad weather blow up and kill all the newly hatched Bees. However, in the event, the cocoons remained for ages in the release box without hatching and so I did end up putting them out altogether because I started worrying that I was going to run out of springtime.
But most of the cocoons did eventually hatch – the whole thing was a success and we are now filled with a bit more confidence to do it all again.
The Red Mason Bee observation boxes also went back up in late March, ready for the Bees to make their nests within.
These boxes had been thoroughly cleaned from last year. Then boiling water was poured over them followed by a drying out in front of the Aga and they even then went into the freezer for a month. So I was pretty confident that these boxes were clean! The outer casing was painted with a non-toxic varnish although the inner wooden blocks were not touched:
They also had an insect barrier grease spread on the gaps and cracks to minimise the chance of parasites squeezing their way in via the back.
The Red Mason Bees mated (the smaller male, with the white fur, on top)
Although this turned into a bit of a mass bundle with other males trying to be involved as well:
Once mated, the females started building their nests in the observation boxes. Eggs were laid on piles of pollen and wet mud used to wall each egg off into a separate cell.
Meanwhile, the parasites gathered in the vicinity looking for a chance to get their eggs onto the piles of pollen instead. Some of the parasites were really beautiful such as this Ruby-tailed Wasp:
The Bee eggs hatched into larvae that ate the pollen and grew:
Once the Bees stopped flying at about the beginning of June we took the boxes inside, wrapped them in tights so that predators couldn’t gain access and kept them under the stairs in the cool and the dark to see out the rest of the summer.
This year, we also had some different Summer observation boxes which went out once the Red Mason Bee boxes came in. These boxes have tunnels of different sizes for summer-flying Bee species.
These summer boxes also went in tights under the stairs as the summer came to an end.
Now that it is October, it is time to harvest the cocoons and clean them up. The two Summer Bee boxes are on the left in the photo below. These species spend the winter as soft larvae rather than hard cocoons and so we can’t remove parasites without damaging the Bees. We will have to leave these boxes as they are and just bring them out next spring so that the Bees can hatch out.
However, the earlier-flying Red Mason Bees have now formed hard, dark-coloured cocoons that can be safely handled.
As well as the cocoons, there is the mud used to build the walls, some unused pollen and a lot of parasitic shenanigans, despite all of those precautions we took.
We used narrow wooden coffee stirrers to push the cocoons out of the wooden blocks:
and put them in batches into a bucket of tepid water. The cocoons float and everything else sinks:
Once they were scooped out of the water, we sand-cleaned them by shaking them in sand vigorously for a few minutes:
We gave them one last dunk to wash off the sand:
and then they were rested on some kitchen roll before going into the cocoon fridge storage box:
Actually, I have ordered a second one of these Humidibee boxes so that the cocoons won’t be so densely packed once it arrives:
And here is their home for the winter, our fridge:
My feeling is that we had fewer healthy Bee cocoons and more parasites this year but I am sure that it varies greatly from year to year and is dependant on all sorts of factors.
But good to have got that all done for another year and already looking forward to seeing them hatch out next spring.