Understanding the role of insects in gardening
While many types of insects, birds and animals seen in the home
are unwanted intruders, others play a vital role in pollinating
plants and moving seeds from one place to another. In fact,
without these animal and insect helpers, most plants would be
unable to reproduce.
Even though most gardeners understand how important this cycle
of pollination and seed disbursal is, few fully understand why
it occurs, or how it benefits both the plants and the animals.
The rewards of pollination and seed disbursal to the plants are
easy to determine - they get to spread their seeds far and wide,
and start new plants in far off locations. The rewards the
insects, birds and mammals derive are many as well, and they
include: Nectar - nectar is actually a sugary solution,
and therefore it is highly prized by all kinds of animals both
for its good taste and for the ample energy it provides.
Getting at this nectar is what prompts most pollinating insects,
birds and animals to do such a good job. Nature has provided
plants with various ways to attract pollinating insects, birds
and animals. Many types of flowers store their nectar in special
glands called nectaries. These nectar glands are most frequently
found in flowers, but they are also sometimes contained in
leaves or other parts of the plant as well. Most plants are
designed to protect their nectar stores from non-pollinating
insects and animals, through the use of special storage
locations that only pollinating insects can reach, for instance.
The use of nectar and the plants, insects, birds and animals
that depend on it is a fascinating study in co-evolution. The
sugar concentrations of many plant nectars have evolved to match
the energy requirements of the types of animals, birds and
insects that pollinate them. For instance, bees require a 30-35%
concentration of sugar in order to make the honey needed by
their larvae in the winter. Therefore, bees will not visit
flowers whose nectar contains less than 30% sugar. Therefore,
the flowers and plants that depend on bees for pollination have
evolved high concentrations of sugar in their nectar to attract
these pollinators.
Pollen - Pollen is also used by flowers and plants to
attract the insects, birds and animals they need. Pollen is
eaten by bees, and it is also used to make a substance called
bee bread, which is a high protein combination of pollen and
nectar. This bee bread is used to feed the larvae, which require
a high concentration of protein to grow and thrive. Some plants,
such as peonies, poppies and roses, use only pollen as a reward
and produce no nectar at all. Other types of plants produce two
types of pollen - their normal pollen and a sterile pollen with
is attractive to pollinating insects.
This evolutionary strategy ensures that the good tasting pollen
will be eaten while the reproductive pollen will be spread to
other areas by the insects, birds and animals that visit the
plant. Of course, this pollen and nectar does the plants no good
if the birds, insects and animals cannot find it, and plants and
flowers use their bright colors and strong scents to attract
these animals and let them know that pollen, nectar, or both
await them. Some pollinating species rely primarily on their
sense of sight, and the bright flowers are used to attract their
attention. Other species, particularly nocturnal ones, rely
primarily on smell. It is the scent of the flowers that attracts
these scent oriented pollinators.