The Tree Bumblebee Arrives In The North West.

The Tree Bumblebee - A Stinger

The Tree Bumblebee

A Sting In The Tale

A new arrival in north west Britain is the Tree Bumblebee (Bombus hypnorum). First seen in Britain in Wiltshire in 2001 this new and invasive bee has spread rapidly and in 2014 was reported as far north as the Scottish border.

Whilst this is fantastic news as this species is an excellent pollinator, there are also some problems with this bee as it can be very aggressive, especially in the vicinity of its nest.

Back in 2012 we started to get a few calls from people who had been stung by bumblebees, a very unusual occurrence unless you actually disturb the nest itself.

There was also a pattern emerging, usually the victims had been mowing the lawn near to a bird box in which the bees were nesting.

The calls were also much earlier in the year and the nests much more advanced than we would expect so early in the spring.

The following year these calls increased and we became aware that we were dealing with a species new to us.

The tree bumblebee or new garden bumblebee to use its alternative name, is common in parts of Europe and Asia, it is so called because unlike our native bumblebee species it likes to nest high up and will often be found in high level air-bricks, vents and bird boxes.

It is a very easy bee to identify with its ginger thorax, black abdomen and distinctive white tail.

Tree Bumblebee colonies are relatively large compared to other bumblebees with 150 – 400 bees per colony.

A bumblebee nest is not an intricate affair like a wasps’ nest, it consists of just a few cells and is usually no bigger than a tennis ball. Often they will be covered in grass clippings or leaves.

Their breeding cycle is very early with active nests being reported before the end of April however it is in May that they begin to attract attention with their ‘nest surveillance’ fights.

Local drones (males) will swirl around the entrance to a nest, often visiting several nests in a day, hoping for an opportunity to mate with newly hatched queens.

This can look very dramatic indeed and is very noticeable, the bees swirling in a swarm-like dance around the entrance to the nest. Often dead and dying bees will be found on the ground below the nest entrance.

Their breeding cycle is normally over by August although in exceptional years there can be a second, smaller breeding phase in the Autumn.

We are often asked if it is necessary to destroy these bees and the answer is that it depends on where they are.

They are very defensive of their nest and sensitive to movement or vibration near to it and they can and will attack if they feel a threat to their nest.

It is a common myth that bees can only sting once and then they die, whilst this is true of the honeybee, bumblebees can sting multiple times.

If the nest is in a location where there is lots of passing traffic, especially children or pets, a low level air-brick for example, then we would advise that it may be safer to destroy the colony.

If it is high up above gutter height, we would advise you to leave them alone and let the colony go full term.

Naturally if they are impeding building work or the dog won’t stop chewing them then it is necessary to take action.

Like wasps a nest is never re-used and does not need to be physically removed, which would rarely be possible anyway.

Please note that these bees, like all other bumblebees are of no use to a beekeeper, they are a totally different bee to the honeybee and cannot be used for honey production.

Please have a thought for your local beekeeper and do not call him/her out to a ‘honeybee swarm’ which in fact turns out to be bumblebees.





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