| [00:01.47] |
Lesson 2 |
| [00:03.26] |
Spare that spider |
| [00:12.39] |
How much of each year do spiders spend killing insects? |
| [00:20.01] |
Why,you may wonder,should spiders be our friends? |
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Because they destroy so many insects, and insects include some of the greatest enemies of the human race. |
| [00:32.57] |
Insects would make it impossible for us to live in the world; |
| [00:37.02] |
they would devour all our crops and kill our flocks and herds, |
| [00:41.92] |
if it were not for the protection we get from insect-eating animals. |
| [00:47.87] |
We owe a lot to the birds and beasts who eat insects |
| [00:52.38] |
but all of them put together kill only a fraction of the number destroyed by spiders. |
| [00:58.64] |
Moreover,unlike some of the other insect eaters, |
| [01:02.57] |
spiders never do the least harm to us or our belongings. |
| [01:08.18] |
Spiders are not insects,as many people think,nor even nearly related to them. |
| [01:15.83] |
One can tell the difference almost at a glance, |
| [01:19.22] |
for a spider always has eight legs and an insect never more than six. |
| [01:26.94] |
How many spiders are engaged in this work on our behalf? |
| [01:31.39] |
One authority on spiders made a census of the spiders in a grass field in the south of England, |
| [01:38.13] |
and he estimated that there were more than 2,250,000 in one acre; |
| [01:45.46] |
that is something like 6,000,000 spiders of different kinds on a football pitch. |
| [01:52.30] |
Spiders are busy for at least half the year in killing insects. |
| [01:58.09] |
It is impossible to make more than the wildest guess at how many they kill, |
| [02:03.38] |
but they are hungry creatures,not content with only three meals a day. |
| [02:09.16] |
It has been estimated that the weight of all the insects destroyed by spiders in Britain in one year |
| [02:15.99] |
would be greater than the total weight of all the human beings in the country. |
