Tree Bumble Bee

Appearance

"Bombus hypnorum" has a short proboscis and a rounded head. The thorax is usually of a uniformly ginger colour, the abdomen is black-haired and the tail is always white. In workers, the first tergite is black-haired, but a proportion of males may have ginger hairs intermixed with the black hair, both on the face and on the first abdominal tergum. On the European continent, individuals with extended yellow coloration exist. Workers are often small, drones are much bigger, and the queens vary in size.

Distribution

"B. hypnorum" is a common bumblebee species in continental Europe and northern Asia, from northern France to Kamchatka in the east, and from the Pyrenees to the mountains in northern Europe. It is not found, though, in the Mediterranean, the Balkans, or the steppes of eastern Europe, only in the mountains of the Iberian Peninsula and not south of Tuscany in Italy. The bumblebee was first observed in United Kingdom on 17 July 2001 close to the village of Landford in Wiltshire, and has since been spreading widely. In August 2008, "B. hypnorum" was found in Iceland, and queens have been found each year since. It likely will continue to stay in Iceland and prosper in close living with humans near dense settlements, i.e. Reykjavík, but will most likely not venture into the more rural parts of Iceland.

Behavior

The tree bumblebee is generally quite docile, but if disturbed, it can defend its nest proactively and it has been known to sting people whom it perceives as a threat.

Habitat

The bumblebee often lives near human settlements. It prefers to build its nest above ground and often inhabits bird boxes. The nest is quite large, with 150 workers or more. The species is a pollen storer; it stores pollen in separate cells and feeds each larva individually, instead of storing the pollen in pockets under larval cells. It visits an enormous range of flowering plants such as "Rhododendron", cherry, grape hyacinth and, in the north, "Vaccinium". It is an important visitor to raspberry and bramble.

Reproduction

The species has a short breeding cycle, with queens emerging early, usually in March. The first cycle is completed from mid-May to early July. A smaller second generation is produced in late summer in favourable years.