Increased Fecundity in Strains of Tribolium castaneum (IIerbst.) and Sitophilus zeamais (Motsch.) after Ten Generations of Selection with Methyl Bromide

摘要

Five strains of Tribolium castaneum （Herbst.) and two strains of Sitophilus zeamais (Motseh.) were selected with methyl bromide for ten generations. Investigation into the reproductive capacity of the progeny compared with that of the parent strains showed increased fecundity in all strains of T. custaneum and in one of two strains of S. zeamais. Changes in tolerance of the selected strains were only of the order of x1.3 at the LD50. However,in quarantine and presbipment treatments with methyl bromide this increased fecundity has implications for the reestablishment of infestations in marginal' treatments thereby increasing the risk of fumigation failure. This could become an important consideration, for example, in fumigation of poorly sealed shipping containers.