Insects have an important role as part of the living planet, and they make up four-fifths of all animal species. But what difference do they make to our lives?
Insects as a problem
Humans have caused some insect species to be moved from one part of the world to another—deliberately or by accident. If the introduced insect species has no natural enemies in their new home, they can become a real problem. A recent UK example is the Harlequin ladybird, which has found its way to Britain and eats other ladybirds.
Some insects can sting, bite, or transmit disease to humans.
So, when it comes to insects, its important to understand the consequences of human actions.
Insects as an opportunity
Insects are very important as pollinators(传粉者). Bees are perhaps the best example of this.
Insects are also useful as models in scientific research. The Fruit Fly is a good example. It breeds rapidly, and can produce very many generations per year in the laboratory, so it is ideal for the study of evolution.
Insects can be useful to the gardener too—ladybirds, for example, are the gardeners’ friend because they eat aphids. Hoverflies and wasps also hunt and kill other insects for food in the garden. These species are called predators(捕食者).
A.Without them, many crops would fail. |
B.Many insect species compete with us for food. |
C.And don’t forget insects can also be eaten by man! |
D.Many of these have been caused by human activities. |
E.Sometimes it is joked that this is because they find us tasty. |
F.Many pests can be controlled by spraying with chemical pesticides. |
G.In fact, many genetic discoveries couldn’t have been made without it. |