The Tree Bumblebee (Bombus hypnorum) is one of the ‘Big 7’ widespread and abundant Bumblebee species found in the UK, despite only arriving in the country in 2001.
Identification: The Tree Bumblebee is a very distinctive species and easy to identify. It has a completely ginger-brown thorax, a black abdomen and a white tail. In males, the first and second abdominal segments may be brown but they are always followed by entirely black segments. Occasionally all black (melanic) specimens can be seen.
Sometimes the bees have worn fur on the central part of the thorax which looks like the bees are going bald. Fur loss like this is unusual in bumblebees so its presence can further aid identification.
Behaviour: The queen usually locates her nest well above ground and bird boxes containing old bird nests are frequently used. Queens have even been observed evicting blue tits from their nest box before taking up residence themselves. As the colony grows, yellow bee faeces can be seen coating the front of the bird nest box as can nest material protruding from the entrance hole. They also nest in tree holes, under roof tiles and eves of houses. Colonies are also frequently seen amongst straw in rabbit hutches and horse stables.
Tree Bumblebees are distributed across mainland Europe, through Asia and into the Arctic Circle. Range expansion meant that they naturally colonised the UK in 2001. Because they have found their own ecological niche by nesting in places that are rarely used by other bees, they aren’t competing with any of our original bumblebee species. In fact they are excellent pollinators and a welcome arrival to our shores.
Colonies can reach sizes of 300-400 bees but the majority of colonies are much smaller. Colonies are short lived and only last for around 4-5 months, sometimes dying out earlier due to attack by the Bumblebee Wax Moth (Aphomia sociella).
Where to see: This is a common bee species and can be seen all across the UK. Tree Bumblebee queens usually emerge from hibernation around late February or March. Owing to their preference for suburban habitats you shouldn’t have any problems seeing one.
Did you know? Male bees cant sting – the stinger is a modified egg laying device (ovipositor) so only females have them.