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Bombus pascuorum identification
workers and males look similar to the queen, but are a little smaller. Lengths, queen 16-18,
workers 10-15, male 13-14 mm.
This queen above has her tongue sheath extended, her tongue is
inside and is longer than the sheath.
Although there are a few species of
ginger coloured bumblebees in the UK this is by far the most common in nearly
all areas. The hairs of the abdomen are lighter in colour to those of the
thorax, and there are a few black hairs. If there is a complete absence of black hairs on the abdomen,
then the bumblebee is probably not B. pascuorum, but either B. humilis or B. muscorum
In a very sunny summer the
hairs of older bees can become faded and appear beige in colour. The thorax is
always covered in hairs, with other bumblebees there is sometimes a bald patch
in the centre of the thorax of older workers and the queen. This can be caused by wear as the bees rub against
the side and roof of the nest, but this is hardly ever seen in Bombus
When I was marking bees in order to follow them and record their
foraging behaviour I found that B. pascuorum was the most difficult to
mark as its thorax was so hairy. Early in the
summer, before it has been bleached by the sun, the hairs are a beautiful, rich
ginger colour as you can see in the photograph above.
Bombus pascuorum, carder bee nests
B. pascuorum nests just below ground in old mammal burrows, or on the surface in grass tussocks. Successful nests can have as many as 150 workers. After founding the average nest lasts for about 25 weeks. The cuckoo species is B. campestris.
Some say Bombus pascuorum can
be aggressive when disturbed, even chasing after people. However when observed
during foraging it is no more aggressive than any of the other species. The
photograph on the right was sent in to me by a visitor to the site, and shows
typical behaviour of scrabbling around in grass, and pulling bits or dried grass and moss into the
pascuorum foraging behaviour
Bombus pascuorum has a medium length tongue and can often be found foraging on
clovers (see below), vetches, blackberries, and later in the year on thyme sage and
lavender. The nectar in these flowers can only be reached by a bumblebee with a medium to long tongue.
Bombus pascuorum nests destroyed by silage cutting
I believe that this bee is
suffering from the recent habit of farmers cutting their grass for silage in
June/July instead of for hay in August.
In Scotland the queens have just
established their nests - Bombus pascuorum is a rather late-starter at nesting - but have few workers when the nests are destroyed by
Some queens will be killed sitting on eggs, others will have the
onerous task of establishing a nest again.
Fortunately it is still a fairly
common bee, and is very valuable for pollinating the more "difficult" flowers such as antirrhinum, left, where an inexperienced forager hesitates before plunging into the gullet of the flower allowing the top petal to fully enclose her. Only a heavy and strong insect such as a bumblebee can get into such flowers.
On the right is a fairly old worker with a full pollen basket foraging on clover. You can tell she is fairly old by the wear to the edges of her wings. This photograph was taken at the end of July on a path at the edge of woodland with open fields on the other side of an old stone wall. This is typical pascuorum habitat
On the right is a worker (female), and you can clearly see the 3 ocelli (simple eyes), as well as the compound eyes.
Bombus pascuorum males
On the left and right is a male foraging on scabious. As you can see he looks pretty much like the workers and queens. The main differences are the rear legs do not have pollen baskets, and also his head has more ginger hairs below the antennae.