Biological studies conducted on house fly breeding in privies in Chatham County, Georgia, during the period 1955–58, have indicated that:
1.In untreated privies, few Musca domestica are produced, but treatment of privies with dieldrin, BHC, or chlordane greatly increased the house fly production therein. DDT, malathion, and Diazinon showed little or no effect on M. domestica propagation.
2.Implants of eggs from resistant house fly strains in treated privies produced 16 to 258 times as many adults as did similar implants in untreated privies.
3.Untreated privies were characterized by heavy infestations of the soldier fly, Hermetia illucens, and by semiliquid excreta. In contrast, treated privies showed few H. illucens larvae and the media were of a semisolid nature.
4.Manipulation of the water content of the media by drainage or the addition of sawdust or dirt caused an increase in house fly breeding similar to that achieved by dieldrin treatments.
5.The increased house fly production in treated privies is a result of a change in the physical consistency of the human excreta brought about by the reduction of H. illucens breeding which had been instrumental in maintaining the media in a semiliquid condition. House fly resistance plays a definite role in the phenomenon, by permitting this species to survive contact with toxicants which are highly lethal to H. illucens. No evidence was found to show that the resistance influenced or stimulated the biotic potential of M. domestica.