The high industrialization of the economy inevitably leads to contamination of the environment, both globally and on the territory of Bulgaria. The effects of the toxic and carcinogenic substances was especially clear in areas with developed chemical and metallurgical industries. The aim of the study was to trace the impact of the heavy metals lead and zinc on the reproduction of the mulberry silkworm. The silkworm hybrids Super1 x Hesa 2, Bax 1 x Svila 2 and Kom 1 were fed with mulberry leaves with high content of heavy metals collected in the area of KCM Plovdiv reported in our previous studies. The following biological parameters were traced: the number of viable eggs in the laying, number of eggs with non-viable fetus, number of unfertilized eggs and hatchability. The high content of heavy metals inhibited the development of the monitored biological traits. There were significant differences in the results for the experimental and control groups. Significant influence was exerted on the number of normal eggs in the laying. There was a high percentage of non-viable eggs with embryos and unfertilized eggs. The lowest obtained results for all the traits were registered for the Кom 1 breed. It was due to the fact that it is a pure monobivoltinna breed and not as resistant to adverse impacts as the two hybrids under study.
Effect of Pb and Zn on the reproductive traits of Mulberry Silkworm (Bombyx Mori L.)