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The bumblebee body can be divided into three main parts to make
identification easy. These are:
The head, which can be quite
difficult to see on a foraging bee as it is deep in the flower.
The thorax which has the wings and legs attached. It is
really just a box of muscles. The biggest being the flight muscles.
The
abdomen which has the honey stomach for storing nectar, the sting, the
wax glands and all the digestive and reproductive organs. For more details on bumblebee anatomy click on the BODY tab above left or here.
A
cuckoo bumblebee, like the bird it is named after, lays its eggs in another
bumblebee’s nest and leaves the workers of that nest to rear the young. Of
course the eggs she lays are either females or males (there are no queens), and the cuckoo females
emerge from hibernation in late spring or early summer, much later than
ordinary bumblebee queens. So by the time the cuckoo females have emerged the
bumblebee queens will have already established their nests. The cuckoo differs
physically from ordinary queen bumblebee in that she has no pollen basket on her rear legs, does not exude wax
from between her abdominal segments, is slightly less hairy than ordinary
bumblebees, and all species have shortish tongues. Cuckoos have a much harder
body than normal bumblebees, and because no wax is exuded there are no weak
points between the abdominal segments, so if there is a fight between a cuckoo
and another worker or queen it is almost impossible for the queen or worker to
force her sting into the cuckoo body. they also tend to have a more pointed abdomen, and because they are less hairy the tip of the abdomen is often visible. Apart from that cuckoo bumblebees usually
have the same pattern of hair colour as the bumblebees' nests they lay
in.
It is thought
that the cuckoo females locate an established nest by smell. She may go right in
and sting the existing queen to death then lay eggs, or she may sneak in the
nest and hide for a few days until she smells the same as the nest, then lay
her eggs. Whatever method she uses it spells the beginning of the end for the
nest because the cuckoo larva consume resources but contribute nothing to the
nest.
Many of the images on this page were taken from Prys-Jones and Corbet's excellent book Bumblebees. As you can see the cuckoos resemble the species whose nests they take over.
It has been decided to rename the genus of cuckoo bumblebees from Psithyrus to Bombus.
Bombus fernaldae
Range: Alaska and Canada south to North Carolina, Tennessee, Colorado, California |
Bombus variabalis
Range: Ohio south to Florida, west to North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Tennessee, New Mexico, Mexico. |
Bombus insularis
Range: Canada south to California, Arizona, New Mexico, Nebraska, New York, Alaska. |
Bobmus crawfordii
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Bombus suckleyi
Range: Alask south to California, Utah, Colorado. |
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