A Comparative Study of the Effects of β-Rays, γ-Rays, and X-Rays on Development in Habrobracon

Abstract

Eggs of Habrobracon juglandis (Ashmead) were subjected, 1-3 hours after they were laid, to [beta] rays from p32, gamma rays from Co60, or 125-kvp X-rays under equivalent physical conditions. At each of the 7 dose levels used dosages were adjusted so that the amount of energy dissipated within the eggs was approximately the same for all three types of radiation. X-rays were most effective in reducing the percentage of eggs hatching, [beta] rays were less effective and gamma rays were least effective in this respect. Histological observations made on embryos exposed at the highest dose level are described. Enlargement of nuclei (up to 3 times the diameter of those found in untreated animals) was a prominent feature of the degenerative changes observed. Although there was indication that cell division continued for a time after exposure, other developmental processes were for the most part completely inhibited. Externally visible structural derangements were seen in damaged eggs but none which were interpreted as being peculiar to any of the types of radiation employed. In general, the time between irradiation and the appearance of visible signs of injury was inversely proportional to the amount of radiation received by the eggs.