How to care for your Red Mason Bee cocoons

Red Mason Bees


In late-March to Early-April once the days are warmer and the threat of overnight frost has past, the release chamber containing the cocoons should be placed into a Mason Bee Nest Box alongside empty nesting tubes. The capped end should be level with the outer ends of the nesting tubes, some of the empty tubes may need to be removed to make space. It is important that the end exit hole is facing outwards and rotated so the sticker covering the exit is at the top (eg. the twelve o’clock position), this is to make sure that no cocoons block the exit when the bees start to hatch. Remove the sticker to uncover the exit hole. Preferably the nest box should be located 1-2 metres above the ground in a sunny south-facing position. Ideally against a wall, a wooden fence or under the eaves of a garden shed or house, ensure the entrance is not covered by vegetation as the bees do not like dappled shade. Position the nest box so the open end is angled slightly downwards to allow water to drain out. Once all the bees have emerged the release chamber can be removed from the nest, you may want to keep this for next year if you wish to release your own cocoons.

Storing Nest Tubes

The bees will lay multiple eggs in the nesting tubes positioned in the Mason Bee Nest Box, gradually filling each one and then capping the end with mud. When each tube is complete, it can be removed and stored in a cool place in an upright position, such as in a flower pot, with the mud plugged end facing up. It is essential they are stored upright so the bee larvae remain in contact with the stored pollen which will be their food source. By October the eggs laid earlier in the year will have hatched into larvae and these larvae will have transitioned into cocoons, there may be some tubes that are only part filled, both these and the full tubes can be stored in the upright position (as above) throughout the winter in an unheated garage or shed, before returning to the garden again next spring. However, for the best results and to avoid parasite build up, the cocoons can be removed.

Removing Cocoons (Optional)

Red Mason Bee Cocoons

This step should not be performed before October to allow sufficient time for the bees to develop into cocoons and enter their dormant state. It is best for the cocoons are recovered before the end of November to remove any parasites. It is also advisable to wear latex gloves when handling the cocoons or wash your hands thoroughly afterwards as some of the debris will contain larvae faeces. Start by gently removing the plastic cap from the base-end of the tube, this part can be tricky so a pair of pliers may be required. As the cap is removed it should also pull with it the paper liner from inside the tube, if not you may need to carefully unwrap the cardboard tube. Gently open the paper liner and search through the contents to find the small, smooth, brown cocoons (pictured). Carefully rub off any foreign matter from the outside of the cocoons before placing them in a container. A clear plastic container with a lid is ideal and will protect them from any inquisitive rodents. Secure the lid and store in an unheated garage or shed for the winter. In late-March, Early-April the cocoons can be placed in a release chamber and put back into the bee nest and sited outdoors as described in ‘Siting’ section above.

Frequently Asked Questions

  1. What should I do if my bees don’t emerge?

    There are no guarantees that all the cocoons will hatch, however we do know that changes in temperature can affect the hatch rate. If, after a couple of weeks of siting, the bees have not started to emerge we recommend that the release tube be taken indoors and placed in a clear plastic tub with a lid. Keep a close eye on it and as soon as the bees start to emerge transfer the tube back to the bee nest and allow the rest of the bees to emerge.

  2. What do I do with the nesting tubes when they are full?

    The bees will lay multiple eggs in each nesting tube and gradually fill them, capping the end with mud. When each tube is complete, remove it and store as per ‘Storing Nest Tubes’ section above. As you remove full tubes you can replenish with empty ones – replacement tubes are available to order.

  3. When is the Red Mason Bee Breeding Season?

    Red Mason Bees are most active on warm sunny days, so their breeding season is very dependent on the weather. They are likely to emerge in April if the weather conditions are favourable and will usually have completed their breeding by the end of July.

  4. What else can I do to help Mason Bees?

    You can provide a source of food for them by planting pollen rich wildlife friendly plants near the nest box. You can also help the bees build their nests by putting out a heap of well sifted, lightly dampened soil a few meters from the nest box which they can use to seal the cells in each tube.

  5. Will the Red Mason Bees sting me?

    Our research team handle the bees regularly and none of them have ever been stung, so the risk is extremely low. The ability to sting is only possessed by the female Red Mason Bee and they will only do so after extreme provocation. The sting is of such low toxicity that even if they do sting it feels like a pin prick.

For any further information please email or call us on Freephone 0800 731 2820.