THE Effect of gamma radiation on the viability and fertility of lucilia sericata mg. (dipt.) irradiated as pupae
1960
Donnelly, Joseph
The biological effects of gamma radiation on Lucilia sericata Mg. were studied by subjecting the pupae to a range of gamma doses from a Cobalt-60 source. Observations were made on the percentage subsequently emerging after each treatment, and their longevity. Fertility was measured by caging each sex with untreated flies of the opposite sex, the numbers of hatching egg clusters obtained providing an index of fertility of the treated component. Percentage emergence, in pupae more than 3 days old at irradiation, was normal up to 12,000 rep, and reduced by about 24% after 24,000 rep. Adult longevity was progressively reduced by doses from 1,000 rep upwards, and was about 50% of the control value after 9,000 rep. The percentage viability of eggs from treated females decreased in the dosage range 0-2,000 rep without any decrease in total eggs produced, after 3,000 rep and above females failed to lay any eggs. Male fertility was about 3% after 3,000 rep; above 3,000 rep males were completely sterile. Morphologically normal sperm was produced by males at all doses up to 24,000 rep, and showed motility up to 6,000 rep at least. Pupae irradiated before completion of a third of the total duration of the pupal stage failed to emerge after 3,000 rep, those irradiated after that stage emerged normally after 12,000 rep. There was evidence that the transition from susceptibility to resistance was abrupt and that the physiological age of the pupae corresponding to this resistance threshold was independent of velocity of pupal development.
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