Read the following passage carefully and answer the questions on it.
Have you always thought that insects are nothing more than a nuisance? Would you like the world to be free of these annoying pests ? Do you spray them swat them. or step on them at every opportunity? Before declaring war on every bug that crosses your path, why not try to learn something about their world? After all, with a population that outnumbers humans by about 200 million to one you can be sure that insects are here to stay! A brief look at just a few of these amazing creatures might well convince you that insects deserve your respect.
Consider flying insects for example: Mosquitoes can fly upside down. Some can even fly through the rain without getting wet – yes, actually dodging the raindrops! Some tropical wasps and bees buzz around at speeds of up to 72 kilometres per hour. One monarch butterfly of North America logged 3,010 kilometres on its migration flight. Hover flies can beat their wings more than a thousand times per second – much faster than humming-birds and dragon flies can fly backwards. Clearly then. insects are such accomplished fliers, unmatched by any other winged creature.
The eyes of many insects serve as a compass. Bees and wasps, for instance, can detect the plane of polarised light. This enables them to locate the sun’s position in the sky – even when it is hidden by clouds. Thanks to this ability, these insects can forage far from their nests and still navigate their way home unerringly.
In the insect world, sounds and aromas are often used to find a mate – no small achievement when prospective mates are few and far between. Female emperor moths find a suitor by emitting a scent that is so potent that a male can i home n on its source from nearly 11 kilometres away. Crickets, grasshoppers, and cicadas prefer to make themselves heard. Even we humans can hear the amorous cicada as it converts its whole body into a sounding board. A large group of courting cicadas can create a noise louder than that of a drilling machine!
Insects play a vital role in our daily life, about 30 percent of the foods we eat results from pollination by them. But pollination is only one of their useful functions. Insects keep the earth clean by means of an efficient recycling system, as they reprocess dead plant and animals. Scientists have observed that without insects the earth will be inundated with dead plant and animal matter. Insects also enrich the soil by liberating nutrients that make things grow. They are sorely missed when their work is not done. Consider what happened in Australia, which has become home to millions of cattle. Herds scattered dung everywhere. Besides being unsightly, the dung provided a breeding site for the bush fiy – a plague to both humans and cattle. So dung beetles were imported from Europe and Africa, and the problem was solved!
Admittedly, some insects eat crops and carry disease. But only about one percent of the world’s insects is considered as pests, and many of these cause damage because of the way man himself altered the environment. Even with their drawbacks, insects are an integral part of the natural world on which we depend. Scientists have pointed out that while insects can survive without us, we cannot survive without them.
(a) In three sentences, one for each, summarise the characteristics of insects discussed in the passage.
(b) In three sentences, one for each, summarise the important functions of insects discussed in the passage.
Explanation
(a)i) Insects are accomplished/skillful fliers. (ii) Insects have good sense of direction. (iii) Insects have keen senses of hearing and smell.
(b)(i) Insects carry out pollination. (ii) Insects enrich the soil. (iii) Insects clean up the earth.