If you have a bee hotel containing cardboard tubes or a wooden bee box with separate units and trays, then October is the perfect time to move out any occupants into a drier and safer place to spend the winter.
You can tell if there are occupants by the number of sealed tubes or entrance holes. Red mason bees (Osmia bicornis), by far the most common bee hotel guests, plug the tubes/entrances with mud after laying their eggs in the tubes or trays, Blue mason bees (Osmia caerulescens) and Orange-vented mason bees (Osmia leaiana) use finely chewed leaf and leafcutter bees (Megachile) make their front door from pieces of leaves. As you can see from the photos above, we only have Red mason bees nesting in our bee hotels.
Behind each plugged entrance there could be seven or eight cocoons from which adult bees should emerge next spring – the males first as they are laid at the front of the tubes, the females at the back of the tubes.
The cocoons started life as an egg laid by the female mason or leafcutter bee. When the egg hatched into a larvae a few months ago it gorged itself on all the pollen its mother had provisioned in the cell and then began to spin a silk cocoon and pupate into an adult bee.
We can help the bees on this journey.
- Some tubes or units can can get damp and mouldy over winter, so I think it’s best to remove them and store in a cool, dry place like a shed. I either pop the whole hotel into a cardboard box and store it there, or just the tubes. And I also store the inside unit of a bee observation box.
- A step further is to open up the cardboard tubes and tease out the cocoons, or prise them out of the detachable wooden bee boxes. The cocoons look like small kidney beans covered in fuzz. This fuzzy stuff is specks of bee poo and could also be parasitic grubs. Dust it off with a soft brush and wipe with a damp cloth until the black cocoons are smooth and shiny (like the photo above)*. Then place the cocoons on some kitchen roll to absorb any excess water before storing them in a cardboard or plastic box with a lid. Put the box in a cold place like a garage or shed. Label the box just in case you forget what’s in it!
- Red mason bee cocoons can also be popped into the fridge as they can be safely stored at around 3-4 C.
- The next step is to thoroughly clean the bee hotel or nest box with a brush and hot, soapy water and bring it inside for winter. The bee boxes will have instructions for how to take them apart and clean.
- Then order new cardboard tubes to put in your cleaned bee hotels ready for next spring.
At the beginning of March, I will explain how to take the cocoons out of storage, but for the next few months you can have peace of mind knowing that they will be safe and sound in their winter home…
* Thanks to Rosybee for the cocoon photo, I couldn’t find any of ours