There are many factors that regulate insect populations. Some of these are weather, which includes temperature, light, moisture, and air movement; migration; food sources; behavior; and genetics. Much of the research compiled on insects is concerned with controlling insect population for the purposes of curbing diseases and damage to crops and livestock. Other research has focused on insects as part of the ecosystem.
For example, mosquitos have been the subject of much research since they can be carriers of malaria (1:546). One of the ways scientists have sought to control malaria is through insect genetics. In the early 1960s, the disease seemed under control. Field workers, using DDT, were able to stop the disease by attacking its transmission routes, or vectors--malaria-carrying mosquitos. However, by the end of the decade, mosquitos developed a resistance to DDT and other insecticides. The mosquitos also became resistant to the technique of swamping insect populations with sterile males to slow down their rate of reproduction. Scientists tried another technique, that of the vaccine, but the malaria parasite, which developed a resistance to the drugs, invaded the candidate vaccines.
Science has now turned to another area, that of genetic engineering, to eradicate the disease. Instead of trying to eradicate the insects, vector biologists are attempting to produce transgenic strains that are incapable of transmitting disease (1:546). Researchers are currently testing for genes that can help insect vectors resist infection with human pathogens, and they are looking for ways to spread these genes through insect populations in the wild.
Another insect, the cockroach, which is considered more of a nuisance than a carrier of a deadly diseases, has also a history of being resistent to eradication. For example, a decade ago, many people got rid of cockroaches by placing small black plastic containers containing a mi...