|
Why Insects Are Important
Insects are very
fertile. And their influence on the nature is, of course,
enormous. Let us talk about their beneficial influence.
The most
important function of insects is pollination of flowering
plants. Flowering plants are the main source of food and
moisture for the majority of insects. At the same time, most of
the flowering plants (that is, those with cross-pollination)
depend of insects-pollinators.
All bright,
noticeable-from-a-distance plants are “advertisements”, by means
of which plants attract insects. Insects are also attracted by
plants’ aroma.
In the corolla of
a flower in the middle, there is a pistil; around it there are
stamens; the ends of the stamens (anthers) contain pollen. For a
cross-pollination plant to bring fruit, it has to be pollinated:
the pollen of one flower has to be brought to the stigma (the
upper part of the pistil) of another one. It is insects visiting
flowers that ensure such pollination.
Insects come to
flowers for collecting pollen (some beetles, many hymenopterans)
or for the sake of sweet nectar (flies, butterflies, many
hymenopterans).
Sometimes insects
use corollas of flowers as an asylum or come inside a flower
cluster for placing there their young. All kinds of insects’
visits are used by plants for pollination.
Many plants
reproduce only thanks to pollination by insects. And we — gather
harvests!
* * *
Honeybees,
silkworm moths and Chinese oak silkmoths, Indian lac insects and
cochineal insects — these are examples of semi-domesticated
insects, bred by man for the sake of products obtained from
them.
Let us recall how
much good man receives from the honeybee! Honey, propolis,
beeswax…
Caterpillars of the silkworm moth produce silk when they build
cocoons; from this silk gentle silk fabric is made.
Another insect —
the Chinese oak silkmoth — also produces thread — even stronger
one.
A very valuable product — shellac — is produced by Indian lac
insects living on certain kinds of trees in South East Asia.
Wax-like substances secreted by them have very good insulating
qualities and are widely used in radio engineering.
In the same way,
mealybugs produce dye.
Many insects are
important for soil formation: they are destroyers of fallen
leaves, dead wood, dung.
For instance,
there was the following interesting case in Australia. Some
pastures suffered from large amount of cow feces that
accumulated and prevented growth of grass. It turned out that in
Australia there were no dung beetles. When dung beetles were
introduced, it helped to decompose quickly the feces and to
increase of the crop capacity of the fields.
Apart from
everything described above — let us remember about the
esthetical role of butterflies, moths, dragonflies, and other
insects that beautify our nature!
|