Bumblebees are mostly social bees that live in colonies in the spring and summer months. There are also ‘cuckoo bumblebees that take over the nests of social bumblebee species. They are crucial pollinating insects for a range of flowering plants – but like, many insects in our countryside, they are in trouble.
Two species of bumblebee became extinct in the UK during the 20th century while another further eight species (a third of the remaining species) are currently listed on conservation priority species lists due to their large-scale declines in distribution.
Bumblebee wings beat 230 times per second, so they need an energy-rich food to power their flight – which is nectar from flowers. They also need pollen from flowers, both so that queen bees can survive winter hibernation (and found new colonies) and also to support the development of the young larvae in the nest.
Bumblebees do not just need flower-rich habitats in which to forage, they require areas that are suitable for nesting, mating and hibernating and all within flying range of foraging sites (up to 1 km). Nests of bumblebees are often in rough, tussocky grass and queens sometimes adapt burrows left by small mammals such as voles. The queen bees over-winter in out-of-the way places, perhaps buried a few centimetres in the loose soil or in old tree stumps or gaps in walls. The hibernation sites are often north-facing, so the queens do not emerge too early in the spring when there is not enough food.
Two species of conservation concern in the Yorkshire Dales are the Bilberry Bumblebee (Bombus monticola) and the Moss Carder Bee (Bombus muscorum).