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Bumblebee and comfrey |
24.5.2003 |
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Robert Burton |
I was doing a little weeding when I
heard a loud buzzing, as of a trapped bee. It was a bee but
it was not trapped. It was avidly examining a drooping
flowerhead of comfrey. Comfrey is sometimes grown because of
its herbal use in healing wounds or as a compost activator
but I grow this rather unruly plant for bumblebees.
I hoped the buzzing would be a case of
'buzz pollination' but there were no more buzzes and I was
unable to confirm it. Buzz pollination is a trick that
bumblebees use to collect pollen from tubular flowers. They
perch over the flower and buzz their wings, faster than they
do when flying, to make the anthers discharge a cloud of
pollen which settles on the bumblebee's furry body. It works
on comfrey and also on tomato, but only in dry weather when
the pollen is powdery. The last week's weather was not
suitable for observing this behaviour.
I have been a little more successful
with finding another relationship between bumblebees and
comfrey. This one is one-sided. Some bumblebees have tongues
which are too short to reach the nectaries of tubular
flowers. So they bite a hole in the base of the flower's
corolla and insert the tongue. It is cheating because the
bee gets the nectar but does not transfer pollen between
flowers. I have found these holes in my comfrey but I have
not caught the culprits at work. The comfrey is now fading
but I can try my luck again when the honeysuckle flowers.
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