The Role of Chemistry in History

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Insect Resistance

April 23rd, 2008 · No Comments ·

Introduction / DDT molecule / Malaria / World War II

Environmental Problems / Insect Resistance / BeginUsing Again?  /  References

There are a few theories as to how certain insects became resistant:

1. Large amounts of a chemical trigger an ‘ancestral response’

  • biological response mechanism to natural toxins
  • the insects that trigger this mechanism were able to develop a resistance and survive–natural selection

2. Resistance could result from behavioral changes

  • the insect learns not to land on certain areas that have the insecticide so they are not genetically resistant but the insecticide is not as efficient.

3. In areas where there is extensive spraying of insecticides the number of resistant mosquitoes increases. Because it speeds up natural selection by “selecting” the mosquitoes that carry the resistant gene and killing the majority of mosquitoes that don’t have the resistant gene.

Tags: DDT