Why,you may wonder,should spiders our friends?Because they destroy so many insects,and insects include some of the greatest enemies of the human race. Insects would make it impossible for us to live in the world;they would devour all of ous crops and kill our flocks and herd, if it were not for the protection we get from insect-eating animals.we owe a lot to the birds and beasts who eat insects but all of them put together kill only a fraction of number destroyed by spiders. Moreover, unlike some of the other insect easter, spiders never do the least harm to us or our belongings.
Spiders are not insects, as many people think,nor even nealy related to them. One can tell the difference almost a glance,for a spider always has eight legs and an insect never more than six.
How many spiders engaged in this work on our behalf?One authority on spiders made a census of spider in grass field in the south of England. and he estimated that there were more tha 2250000in one acre;that is something like 6 000 000 spiders of different kinds on a footall pitch. Spiders are busy for at least half the year in killing insects. It is impossible to make more than the wildest guss at how many the kill,but the are hungry creatures, not content with only three meals a day. It has been estimated the weight of all insects destroyed by spiders in Britain in one year would be greater than the total weight of all the human beings in the country.