The combined effects of acute irradiation and food supply on survival and fertility in Daphnia magna.

The results of recent studies have provided strong evidence for the combined effects of diet restriction and exposure to chemical on the survival and reproduction of aquatic organisms. However, the combined effects of diet restriction and exposure to ionizing radiation remain poorly understood. To establish whether parental irradiation and diet restriction can affect the survival and fertility of directly exposed crustaceans and their progeny, Daphnia magna were given 10, 100 and 1000 mGy of acute γ-rays either during chronic diet restriction or normal food supply. Acute exposure to 1000 mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. Similarly acute exposure to 100 and 1000 mGy also significantly compromised the fertility of F0 and F1Daphnia and did not affect the F2 generation. Low level of food supply compromised the viability of non-exposed and irradiated Daphnia, whereas their fertility was substantially affected by all diets. The dose-response for the effects of irradiation on viability and fertility of Daphnia received different food supply were practically similar, thus implying that the level of nutrition and acute exposure to ionizing radiation independently affect the life history traits in crustacean.