Genetically Nontransmissible Nuclear Damage Induced by Ultraviolet Radiation in the Wasp Habrobracon.

N Habrobracon, unfertilized eggs develop normally and become haploid males; I fertilized eggs become diploid females. It has been observed that when newlylaid eggs from virgin females are exposed to ultraviolet radiation on the nuclear (convex) surfaces, embryo hatchability decreases as the exposure time is increased (VON BORSTEL and MOSER 1956; VON BORSTEL and WOLFF 1955). Most of the deaths occur very early in development. However, if the eggs are fertilized before irradiation, the frequency of early deaths is markedly reduced, and preliminary experiments indicated that the fertilization-induced recovery from ultraviolet damage was indeed complete (VON BORSTEL 1961). (Operationally this is a “protection” since the modifying treatment (fertilization) takes place before irradiation, however there appear to be no interactions between egg and sperm nuclei until meiosis is complete and this occurs after the irradiation.) A similar reactivation effect seems to occur after fertilization of eggs from females treated with nitrogen mustard (LOBBECKE and VON BORSTEL 1962). The study reported here was undertaken to determine definitively: (1 ) if the fertilized induced recovery is indicative of a true repair of ultraviolet-radiationinduced damage, a postponement of death to a later stage (cf. ATWOOD, VON BORSTEL and WHITING 1956), or a large contribution of recessive lethals to the death of the unfertilized (haploid) egg, (2) the stage or stages of death in the unfertilized and fertilized egg, and ( 3 ) if the fertilization-dependent recoverable portion is identical to the photorecoverable portion of ultraviolet radiation damage.