The Clonopsis gallica puzzle: Mendelian species, polyploid parthenogens with karyotype re-diploidization and clonal androgens in Moroccan stick insects (Phasmida)

The stick insect Clonopsis gallica is a morphologically stable obligate parthenogen, ranging from North Africa to southern Europe, with a variable karyotype (54–57 chromosomes), considered diploid or triploid. Clonopsis gallica origin and relationships with Clonopsis algerica and Clonopsis maroccana remained unknown. Our Moroccan samples shared the same egg and body patterns and, in addition to C. gallica (2 n  = 54, XX), comprised the new bisexual Clonopsis sp. 1 (2 n  = 35/36, X0/XX) and the new all-female Clonopsis sp. 2 (2 n  = 72, XX), apparently forming a numerically polyploid series with re-diplodized karyotypes; C. gallica could thus be a triploid hybrid in origin. Furthermore, two strains of ameiotic males with 2 n  = 35 (X0) or 53 (X0) were found, which would maintain themselves as clonal androgens. We could conclude that in stick insects body and karyotype 'phenotypes' are considerably independent, thus preventing a sound taxonomy. Generally, the high heterozygosity of hybrids allows parthenogens to persist for long, particularly when hybrid polyploids are produced, as backcrosses of the hybrids to the parental species allow repeated incorporations of genetically diversified genomes. The distribution range of Clonopsis parthenogens appears to realize a sound instance of geographical parthenogenesis.