A. D. OBRETENCHEV
St. Kliment Ohridsky Sofia University, Department of Biology, BG-1000 Sofia, Bulgaria
OBRETENCHEV, A. D., 2003. Influence of gamma-radiation on different ontogenetic stages of Trogoderma versicolor Creutz. (Coleoptera: Dermestidae). I. Egg and embrionic development. Bulg. J. Agric. Sci., 9: 725–728
Experiments to establish the influence of gamma-radiation on eggs of Trogoderma versicolor Creutz (Coleoptera: Dermestidae) were provided at Plant Protection Institute, Kostinbrod, Bulgaria. All irradiations were done in gamma-irradiator 'Issledovatel' (60Co, dose rate 629 rad.min–1 ≈ 6.3 Gy.min–1) under conditions of temperature 20° ± 1 °C and relative humidity 70 ± 5 %. One day old eggs (24 h) were irradiated with doses from 5 to 60 Gy and 6 days old eggs (144 h) with developed embrio with doses from 10 to 130 Gy. It was established that the development of the embrio of one day old eggs irradiated with doses from 5 to 10 Gy was faster – average 5.96 days, but with the rise of the doses it was longer – average 11.16 days at 35 Gy. Dose of 40 Gy was lethal for newly laid eggs of T. versicolor.
Doses from 10 to 80 Gy didn't affect the percent of hatching of irradiated 6 days old eggs. With the rise of the doses this percent was lower. Dose of 120 Gy was lethal for 6 days old eggs. The hatched larvae from irradiated 6 days old eggs with doses from 60 to 80 Gy died at second instar, but they fed till now. The larvae hatched from 6 days old eggs irradiated with doses from 90 to 110 Gy died at first instar and didn't fed. The emerged insects from irradiated eggs with dose of 50 Gy in most cases had deformations of the elytrae , depigmentation of hole body or parts of it.