Effects of gamma-radiation on mature pupae of maize borer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae)

Abstract

Mature (5- to 6-day-old) male and female pupae of C. partellus were irradiated at 5 to 20 kilo-Roentgen (kR) and 5 to 10 kR respectively. Emergence of normal appearing moths, pupal periods and adult longevities remained statistically unaffected. Fecundity of normal (nonirradiated) females mated with males irradiated as pupae was nonsignificantly different from control, but fecundity of females irradiated as pupae at 10 kR was significantly reduced when they were mated with normal mates. Dominant lethals of varying intensities were induced at 5–20 kR. However, induction of dominant lethality was sex- as well as dose-dependent. Radiation doses inducing 100% dominant lethals in sperm (20 kR) and ova (5 kR) did not mitigate the mating ability of males and receptivity of females. However, receptivity of females was reduced significantly when they were irradiated as pupae at 10 kR. Rates of embryonation in F1 eggs were significantly reduced when normal females were crossed with males irradiated as pupae at 20 kR, but similar effect was observed at 10 kR in reversed crosses. Embryonic development was delayed in eggs obtained from crosses, where male or female parent was irradiated in pupal stage, but in both cases most of the dominant lethals acted late in embryonic development.