Effect of carbon dioxide on the radiosensitivity of adult confused flour beetles

Adults of Tribolium confusum duv., were subjected to several concentrations of CO2 in air and then exposed to gamma irradiation one day and 7 days later. The beetles became more radiosensitive when exposed to CO2 followed by irradiation within 24 hour. This effect started to appear 7 days after irradiation in the treatments of the highest CO2 concentration (46%) and 10 or more krad., increased after 14 days and reached to almost complete mortality after 21 days. On the other hand, exposure of the insects to CO2 and then to irradiation after 7 days did not show any effect. Slight effect began to appear after 14 days and did not reach complete mortality after 21 days, except at the highest concentration of CO2 followed by treatment with 20 krad or more. Thus, irradiation of the beetles within 24 hr. after exposure to CO was more effective than within 7 days. Generally, the treatments of CO2 followed by gamma irradiation induced higher percent mortality than either treatment applied alone.3 tab