AUTOMICTIC PARTHENOGENESIS AND ITS GENETIC CONSEQUENCE IN BACILLUS-ATTICUS-ATTICUS (INSECTA PHASMATODEA)

The meiotic divisions in the eggs of the diploid thelytokous stick ins ect Bacillus atticus atticus (2n=34 or 33) were examined in Feulgen sq uashes. The reduction division is normal and results in two interphase nuclei. These nuclei fuse at the onset of prophase II and a diploid m eiotic division II follows. One of the resultant nuclei degenerates an d the other starts embryogenesis. This automictic type of parthenogene sis explains the clonal maintenance of cytotypes and also the transmis sion of different levels of heterozygosity. The degree of heterozygosi ty is determined by the position of the chiasmata and the orientation of the chromosomes at metaphase II. The production of diploid B. attic us/rossius hybrids and its underlying mechanism are discussed.