Bumblebee hives will benefit from weather protection and extra insulation around the box if used in unheated greenhouses or outdoor crops, especially in winter or spring. Much like it is for us, a warm dry home is a healthy home and more insulation would never go astray, but ensure there is still adequate ventilation as the bumblebees need to breathe!
Bumblebees are warm blooded insects, while they can survive with low body temperatures, it is not conducive to activity or brood development. Bumblebees can fly in much cooler conditions than honeybees, but to do so they need to maintain a thoracic temperature of greater than 30oC, which they can actively manage while at rest or more ideally during flight. This is one of the reasons why bumblebees are such efficient pollinators, by actively maintaining their internal body temperature they can work in a wider range of conditions, and they also benefit by continuing to move, so tend to move more quickly between flowers.
To promote development, bumblebees also expend energy to keep their young at around 32oC. If the conditions are cool and the insulation is poor, more bees will be involved in heating the hive, thereby reducing its overall activity, and condensation can build in the hive creating an unhealthy environment and reducing the overall bee numbers.
Where possible avoid clumping all your hives together, rather spread them throughout the crop to improve coverage. Bees may not forage in the immediate vicinity of their own hive, so spreading hives out means bees will forage around the other hives. Placing them within the crop may promote activity on your flowers.
Morning sunlight helps warm the hive at the coolest time of the day and may help increase early morning activity. Peak day sun can over heat hives and should be avoided, especially during spring and summer conditions.
Agitated bees can get lost or sting you. It is best to wait at least 30 minutes after positioning the hive before opening it, as the hive may have become agitated during transport, and outgoing bees may not perform adequate navigation flights if unsettled. Ideally the activity of the hive will be slow to begin with, this is normal and gives the best outcome. It is best to give the hive some space after opening the box as your absence later may confuse the bees, making it harder for them to find their home again.Icons sourced from the Noun Project, click here to see acknowledgements.