Recently, elevated levels of aneuploidy were described in laboratory lines of free-living flat worms Macrostomum lignano . During its evolutionary history this species has undergone whole genome duplication followed by chromosomal rearrangements . In this species, chromosome abnormalities might have disturbed the delicate gene balance, but instead did not lead to any abnormal development or pathological phenotype. Thus, it is at least possible that, in parthenogenetic females of polyploid species, phenotypically normal linages characterized by chromosome abnormalities can arise. These lineages can be an evolutionary dead end or can generate new diversity for further natural selection and evolution. Application of molecular in situ approaches for reliable karyotyping of individual samples of Phasmatodea is required to answer the question of comparative molecular cytogenetics of different strains of polyploid species in stick insects.