Agriculture Reference
In-Depth Information
However, certain types of honeydew (for example, that excreted by leaf hoppers when
feeding on the Tutu bush in New Zealand) are poisonous and have caused many
problems in the past - which emphasizes the need for beekeepers to know which plants
their bees are feeding on and at what time of the year.
Spreading pollen
Pollen is what bees are all about. Pollen is produced by the flower's anthers and, when
the anthers dehisce or open, the pollen travels to the stigma of a receptive flower. How it
'travels' varies with the flower/plant. Grass pollen is mainly moved around by wind, and
this is what causes hay fever in allergic individuals. Many pollens come into contact with
and adhere to bees and other insects and, when the insect brushes against the stigma
of a receptive flower, pollination occurs. Some flowers use both wind and insects for
pollination, such as the olive, and, in this case, the bee assists in the pollination process.
The cucumber plant is a typical example of pollination. The male flowers have pollen
and nectar. The bee is attracted to the nectar and, while taking it, pollen adheres to its
body because the pollen grains have a tiny negative charge and the bee a tiny positive
charge. Bees also have very hairy bodies with plumose or multi-branched hairs that can
collect and hold pollen grains. The bee may then move to the female flowers on another
cucumber plant attracted by the nectar it offers. While the bee is taking this nectar, the
pollen comes into contact with the stigma of the plant sufficient for pollination to take
place.
Harvesting the pollen
The bee in the above example is almost an accidental pollinator: its main target is the
nectar. Bees, however, also use pollen as a protein-providing food for brood and young
adult, maturing bees, and so a proportion of the foraging bees collect nectar and pollen
while some collect just pollen. The bee 'combs' itself and, by doing so, cleans out the
grains and packs them into what are called the corbiculae or pollen baskets on its hind
legs. Have a look at the entrance to any beehive during the active season and you will
easily see these pollen loads - they look like small round suitcases on the bees' legs.
