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Darwin, Charles, 1809-1882

"Effects of Cross and Self Fertilisation in the Vegetable Kingdom"

They work so
industriously and effectually, that even in the case of social plants,
of which hundreds of thousands grow together, as with the several kinds
of heath, every single flower is visited, of which evidence will
presently be given. They lose no time and fly very quickly from plant to
plant, but I do not know the rate at which hive-bees fly. Humble-bees
fly at the rate of ten miles an hour, as I was able to ascertain in the
case of the males from their curious habit of calling at certain fixed
points, which made it easy to measure the time taken in passing from one
place to another.
With respect to the number of flowers which bees visit in a given time,
I observed that in exactly one minute a humble-bee visited twenty-four
of the closed flowers of the Linaria cymbalaria; another bee visited in
the same time twenty-two flowers of the Symphoricarpus racemosa; and
another seventeen flowers on two plants of a Delphinium. In the course
of fifteen minutes a single flower on the summit of a plant of Oenothera
was visited eight times by several humble-bees, and I followed the last
of these bees, whilst it visited in the course of a few additional
minutes every plant of the same species in a large flower-garden. In
nineteen minutes every flower on a small plant of Nemophila insignis was
visited twice. In one minute six flowers of a Campanula were entered by
a pollen-collecting hive-bee; and bees when thus employed work slower
than when sucking nectar.


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