Genetics of Mosquitoes

Abstract

Some of the implications of the studies on mosquito genetics are reviewed. Some of the practical implications of research on the genetics of insecticide resistance have been dealt with by Davidson. Of perhaps the greatest importance is the ability to detect resistance, particularly to dieldrin, by the use of discriminating dosages. In these dosages is provided the tool necessary for population dynamics investigations, although, so far, few such investigations have been made. The findings that dieldrin resistance is always of a very high order and semidominant in its genetic expression and that DDT resistance, in anophelines at least, is of a comparatively low degree and usually recessive, have led to the realization that the rates of selection must be very different. This has led to the increased use of DDT in malaria eradication schemes in the hope that eradication of the disease may be achieved before vector resistance interferes. In addition, the use of mixtures of insecticides, having different modes of action and producing different mortalities on susceptible and resistant mosquitoes, is now being recognized as a possible fruitful approach to the prevention of the appearance of resistance. Changes in mosquito populations as a result of the selective effects of insecticides, other than the appearance of resistance, may present problems for those concerned in the eradication of mosquito-borne diseases. Some of these have been indicated by Mattingly. Such changes as have occurred give some clue to the variations in genetic plasticity of a species in relation to its distribution and possible indications of its evolution. A. gambiae and A. darlingi are interesting examples in illustration [Mattingly]. Our ever-increasing knowledge, accumulating from hybridization and speciation studies and from cytogenetic investigations, must invariably shed greater light on such problems.