Mosquitoes became resistant to DEET through mutation and natural selection.
Natural selection selects beneficial alleles, which increase their frequency in the population, resulting in adaptation. Aptitude, which is the contribution of each genotype to the next generation, increases too.
In many cases adaptations, resulting from the natural selection process can be correlated to environmental factors or selective pressures applied by other organisms or habitats.
The DEET repellent is the selective pressure or modeling environmental factor.
Some mosquitos had mutations that altered their behavior.
The new mosquito's response is not-detection of repellent presence (only in those harboring the mutations).
These mutations benefit from natural selection.
Mosquitoes live and adapt to their environment.
Some mosquitos in the population most likely developed a mutation that favored them.
DEET, a repellent, was not detected. These individuals gained resistance to the chemical and were able to survive and reproduce, resulting in an increase in population size. Natural selection favored the resistance-inducing mutation.
Repellents may cause a genetic change in insects, causing them to be unable to detect the chemical. Insects have evolved to be able to tolerate the DEET dose that is commonly used to repel mosquitos.
Learn more about mosquito adaptation here:
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