Repair of X-Irradiation Damage in TRIBOLIUM CASTANEUM Strains Selected for Differences in Developmental Rates

Lines previously selected for different speed of development were found to differ in their spontaneous and induced wing abnormalities after single exposure to X-ray (10 KR) in Tribolium castaneum at 33 degrees and 70% relative humidity. At the time of irradiation the mean developmental time (from egg to first day pupa) was 16.9, 18.8, 22.8 and 18.4 days for fast, intermediate, slow and unselected lines, respectively. There was no difference between males and females in their responses. The spontaneous rate (angular values) of wing abnormalities was 5.3%, 11.2%, 3.5% and 7.2%, and the corresponding induced values were 16.7%, 20.5%, 11.7% and 25.2% for fast, intermediate, slow and unselected lines, respectively. The difference between the spontaneous (due to selection) and the induced (due to selection and irradiation) rates indicates that slowing down development will probably increase the efficiency of the repair of the irradiation damage. This difference (angular values) was 11.4%, 9.4% and 8.1% for fast, intermediate and slow lines, respectively. Increasing developmental time by one day resulted in repairing 0.56% of the radiation damage. These results indicate that both the genetic and the developmental state of the line influence both induction and repair of the X-irradiation damage. The relationship between development, cell cycle, protein synthesis and repair is discussed.