Fifty years ago, bed bugs were nearly eliminated in the United States by using of pesticides like DDT. Today bed bugs are back in beds and theaters. DDT is no longer used due to environmental issues. Pyrethrums are currently the top choice for bed bug infestations. Pyrethrums are especially useful to us because they generally have a stronger effect on bugs than on humans and animals. Some bed bugs had mutations in their genetic code which allowed them to survive the chemical pesticide and they produced chemically resistant offspring. How can this be explained?

Since a mutation cause them to build up a resistance two chemicals they are more likely to survive and reproduce. since most of the bed bugs that are not resistant will die off it is very likely that two chemically resistant bed bugs will mate and reproduce resulting in a almost a hundred percent chance that The Offspring will also be chemically resistant. or the bedbugs could go through a process of natural selective breeding where the parents that are chemically resistant purposely breed with other chemically resistant bed bugs knowing that their offspring would be more likely to survive based on past experience.