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04-24-03
Bees and Flowers Play the Pollination
Game
Flowers and bees! Bees and flowers! No matter how you look at it, you
really can't separate the two. In the natural order of things, bees depend
on flowers and flowers depend on bees.
This flower and bee thing is what scientists call mutualism. It is a
partnership where both participants benefit from the association. So how
does it work?
Like a lot of things in nature, it all boils down to reproduction. One
of the most common reproductive approaches used by plants is based on
seeds. Production of seeds begins when pollen from the male parts of a
plant contacts the female parts of a plant. Then some X-rated things happen
involving pollen tubes, styles and other plant parts. Ultimately, a seed
develops.
If both the male and female parts are from the same plant, the process
is called self-pollination. If the male and female parts are from different
plants, that is called cross-pollination. Cross-pollination is good since
it results in gene mixing and what has come to be known as hybrid vigor
in the offspring.
Plants, unlike animals, can't go searching for mates. Instead, plants
just send their pollen in search of mates. Send may not be the correct
word. The pollen has to be transported. Sometimes the pollen is carried
by the wind. Other times pollen is carried by insects.
Several groups of insects transport pollen from flower to flower. Beetles,
butterflies and wasps have been shown to carry pollen. However, one group
of insects, the bees, are the premier pollen bearers of the insect world.
Unlike other insects that transport pollen by accident, the bees do so
intentionally.
Bees and flowers actively play the pollination game. The process is one
of the miracles of nature. But neither the flowers nor the bees play the
game just for fun. We're talking serious biological business here. The
flower has a job that needs to be done. It needs pollen transported. The
bee needs food to feed its family. This is the biological version of "Let's
Make A Deal!"
Flowers produce a fine quality food called nectar. This sweet substance
is utilized by many insects. Unlike other insects, bees have developed
a process to refine and store nectar as honey.
So what we have here is a classic economics problem. Flowers have a raw
material that is needed by bees. But economics teachers warn that you
can't stay in business if you sell products below costs. This is true
of flowers. So nectar is bartered. Bees provide a pollen transport service
in exchange for nectar. In order to ensure that the bee carries out its
part of the deal, the flower does not provide a full load of nectar for
a bee. Each flower provides just enough nectar to entice the bee to feed.
It must go to other flowers to complete the load. When that happens, pollen
is transferred from flower to flower.
But in the rough-and-tumble world of business and nature, it is not enough
to provide a wonderful raw material like nectar. The plant has found that
it pays to advertise! Plants do so with flowers. The flowers function
to attract the bees to the plant. Once there, the bee makes its way to
the nectar distribution center. On the way, it crawls by the pollen-dusting
facility where grains of pollen stick to hairs on its body.
So what if the bee seems to have been tricked into carrying the pollen
for the plant? Remember, "All's fair in love and war!" And in
pollination, apparently.
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