Gamma radiation susceptibility of strains of Tribolium castaneum (Herbst) resistant and susceptible to fenvalerate

Gamma radiation susceptibility of adults of the fenvalerateresistant strain of Tribolium castaneum (Herbst) (Coleoptera : Tenebrionidae) was studied under laboratory conditions. Selection for resistance to fenvalerate in adult beetles was carried out up to the sixth generation. In each generation of selection, adults of the fenvalerateresistant strain were evaluated for susceptibility to gamma radiation and compared with their fenvalerate-susceptible counterparts. Susceptibility to 60Co gamma radiation was evaluated on the basis of dosage-mortality (LD50) and time-mortality (LT50) responses. We found the LD50 values for the fenvalerate-resistant and -susceptible strains to be 89.16 and 97.46 Gy respectively, showing no significant difference in susceptibility to gamma radiation. LT50 values were 7.58 and 17.20 days for the fenvalerate-resistant and -susceptible strains respectively, showing that mortality in the resistant strain occurred markedly earlier than in the susceptible strain. (author)