THE EFFECTS OF ACUTE GAMMA IRRADIATION ON THE BRINE SHRIMP, ARTEMIA. III. MALE F₁ REPRODUCTIVE PERFORMANCE FOLLOWING PATERNAL IRRADIATION OF MATURE SPERM

¹ Biology Department, Long Island University, Brooklyn, New York 11201

Male brine shrimp (Artemia) were hatched from commercially obtained Californian cysts and irradiated as adults with acute doses of 0, 1, 2, 3.5, 5 or 10 kR gamma rays. Each male was individually pair mated to a white eye female. The F₁ were raised to maturity and scored for survival to adulthood, sex ratio, and F₁ male reproductive performance. There was a significant decrease in F₁ survival to adulthood after paternal doses of 3.5, 5 and 10 kR, but not at lower doses. A significant increase in male sex ratio was observed after 5 and 10 kR, and these males were almost completely sterile. A paternal dose of 3.5 kR resulted in a 44 per cent decrease in the number of fertile males and some fertile males were semi-sterile. No apparent effect was observed after 1 or 2 kR.

These data support the proposed holokinetic nature of the Artemia chromosome. They also demonstrate that the observable effects of radiation may be much more extreme in the F₁ animals than in the irradiated generation itself. This observation has important implications when assaying the effects of radiation on natural populations.