Tree bumblebee
(Bombus hypnorum)
Credit: Nikki Gammans
Status
This is one of the Big Eight common and widespread bumblebees.
Where to find
They are found in most habitats (gardens, parks, and the wider countryside).
UK distribution map
Tree bumblebee (Bombus hypnorum)
Map shows in dark green, the current known distribution for this species.
References
More detailed information on sources can be found here.
Credit: Jade Oliver
Active period
Tree bumblebee queens emerge from hibernation from February onwards.
Workers appear roughly 6 weeks after the nest is established and new queens and males are produced towards the end of the two to three month nesting period.
Tree bumblebees usually nest above ground in bird boxes and in roof spaces. Nests can have up to 150 workers. Males show a distinctive behaviour where large groups fly around outside a nest entrance. They are waiting for new queens to emerge so they can mate with them.
This species often has a partial second generation and can be seen up to the end of August.
Description
All three castes (queen, worker and male) have the same appearance, with an entirely ginger brown top to the thorax followed by a black abdomen and a white tail. In males the ginger brown hair can extend on to the front of the first section of the abdomen.
Some individuals appear very dark with little ginger brown hair on the thorax, although the white tail remains. This process is known as melanism (and individuals are referred to as melanic) because of the increased production of the dark pigment, melanin. Production of melanic individuals occurs in virtually all bumblebee species but seems to be particularly prevalent in Tree bumblebees.
This species has a short tongue, and it often feeds on the flowers of brambles, raspberry, and cotoneaster.
Similar species and differences
The Common carder bumblebee (Bombus pascuorum) has similar ginger brown hair on top of the thorax, but the sides of the thorax are pale (black in Tree bumblebees). Common carders also have a mixture of brown, cream and black hairs over the entire abdomen and never have a white tail.
Melanic individuals can be produced by most bumblebee species (most commonly by the Tree, Garden, Ruderal and male Field Cuckoo bumblebees) and reliable separation in the field can be very difficult.
