A population of Anopheles mosquitoes reaches very high densities, and is subject

Question

A population of Anopheles mosquitoes reaches very high densities, and is subjected
to aerial spraying by DDT. The following six years, the mosquitoes are not observed at
all, but the population was sprayed “just in case”. An outbreak occurs sevem years later,however, and this time, the aerial spraying with DDT is much less effective. Laboratory tests indicate that these mosquitoes are resistant to DDT, avoiding surfaces coated with it.It also seems that they have a reduced growth rate and lower fertility than mosquitoes from previous years. Field ecologists report that virtually every predatory insect has been eliminated from the regions sprayed with DDT.
a.What type of evolutionary event has occurred here? What was the likely
mechanism for the change in the mosquito population?
b.What recommendations would you make as a mosquito control strategy for the future

Explanation / Answer

The ones that were more resistant to the DDT survived, thus they were the only ones who reproduced and after a few sprays the whole population were the ones that survived. My recommendation would be to change the chemical used every year, then no resistant mosquitos would reign. It is due to natural selection. The more resistant ones have better reproductive success so their genes (including the resistant one to DDT) gets passed on. over time, the population of mosquitoes has a higher frequency of that gene in their population (more are resistant to DDT).

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