Bumblebees depend almost entirely on flowers for their food and, like us, they benefit from a varied diet.
They use nectar from the flowers as a source of fuel, as it is high in sugar. The pollen provides the protein and nutrients needed for growth and development. It is therefore unsurprising that the best habitats for bumblebees are those that offer plenty of flowers to feed from during the entire active phase of the bees’ lifecycle (from spring until late summer). This will ensure that there is a good supply of pollen at all of the crucial times:
- When the queens are establishing nests.
- When nests are growing.
- When nests are producing new queens and males.
- When queens are fattening up ready for hibernation.
It is also important that the flowers present are useful for bees. Certain plants have flowers that have shapes that bumblebees cannot use. For example, some flowers have petals that form long tunnels which are too long or narrow for the bees to feed from. Other flowers may not be suitable because they produce little or no pollen and nectar, often as a result of selective breeding by horticulturalists for their pleasing appearance. Plants like pansies and double begonias offer little for bumblebees and other pollinators.
It is very easy to find plants for the garden that are good for bumblebees. Visit our Bee kind gardening tool to find out which flowers are best for bees. More information on providing larger areas of land for bees can be found in our ‘Managing land for bees’ section.
What bumblebees look for in a nest site
Nest sites vary between bumblebee species. Most of the commoner species prefer dry, dark cavities and nests can turn up in a variety of unexpected places. Other species prefer tussocky grass or leaf piles and occasionally nest in compost heaps.
When searching for a nest, the queen will investigate the environment using both sight and smell. When she finds a potentially suitable site she will investigate by going into the hole. If it proves unsuitable she will continue searching until she finds a nest site. The distinctive low-flying zig zag flight of a nest-site searching queen is seen in spring and is very distinctive.
In gardens, bumblebees tend to nest in relatively undisturbed areas such as shaded corners. Some will also nest under structures such as sheds. They do not like to nest in areas with prolonged exposure to the sun as this can heat the nest too much.
Bumblebee nests vary in size depending on the species and time of year. A well-established nest may contain up to 400 bees. Honeybee hives typically contain 50,000 bees so bumblebee nests are very small in comparison.
What bumblebees look for in a hibernation site
Only new bumblebee queens go into hibernation over the winter. Very little is known about the preferences for hibernation sites, and how this differs between species. However, some research suggests that they prefer to hibernate in north-facing banks, where they dig into vegetation and loose soil. In this soil they form a small chamber, in which they spend the winter. It is not uncommon for people to find bumblebees hibernating in their compost heaps or in soil beds in their gardens.
"We are facing a fundamental problem with the decline of bees and other pollinators. They have an absolutely crucial role in pollinating many of our important crops - without them we will face higher food costs and potential shortages."
Professor Douglas Kell
BBSRC Chief Executive