Release of Sterile Males into Natural Populations of the German Cockroach Blattella germanica

摘要

A pilot experiment in genetic control of the German cockroach Blattella Germanica, was conducted aboard a small vessel based at Norfolk, Virginia. It utilized 'sterile' (double translocation heterozygotes) whose sterility effects were due to embryonic lethality plus complete entrapment of any remaining viable embryos within the egg case. Initial infestations were reduced by insecticides prior to male release. Three releases of unmated sterile males were made at monthly intervals. Infested harborages, located in the course of insecticide application, were used as release sites. The experiment was terminated after 4 1/2 months. The results showed that released sterile males joined groups near release sites and that they competed well against wild type sterile males. Apparently neither they nor females with which they mated moved far from these sites. Sterility effects differed in respect to specific sites and general areas. Population growth was retarded markedly in the galley, the area of heaviest initial infestation. Terminal infestation was heaviest in the mess-deck, although the highest sterility among females occurred at near the mess-deck release site (only one mess deck-infested site was found prior to initiation of the experiment). A slight increase in the number released might have suppressed/eliminated groups inhabiting galley harbor, but that site selection was the major problem in the mess deck. Analyses of nymphal age classes and mating types among females led to a hypothesis that insecticide-induced dispersal of nymphs resulted in the infestation of many new mess-deck harborages. Population growth was unchecked at these sites because they were too far removed from the sterile male release sites. Keywords: Reprints.