The Department of Agriculture decreed that since sparrows were a threat to the harvest, they had to be done away with. So they were. And as a result swarms of insects, which sparrows normally keep under control, descended upon the fields and ate them bare. Then the government found a solution for this: costly insecticides. These chemicals made foodstuffs more expensive but also proved harmful to health. All too late did people come to realize that though the sparrows had lived off the grain in the fields, they also kept the food healthy and cheap.
-Tony de Mello
It is a clear example of what happens when we interfere with the nature and upset the well-designed order in nature, where every creature has its place and function to perform for the welfare of the total – I have not yet been able to figure out the ordained purpose of mosquitoes, nevertheless there must be some unique reason to justify their existence.