PROPHAGE ELEMENTS FROM THE ENDOSYMBIONT, WOLBACHIA HERTIG, 1936 TRANSFERRED TO THE HOST GENOME OF THE WOODLOUSE, ARMADILLIDIUM VULGARE LATREILLE, 1804 (PERACARIDA, ISOPODA)

Males with female genital apertures (male fga) have been collected in wild populations of woodlice harbouring Wolbachia bacteria. Sexual traits of these functional males indicated they underwent a postponed sexual differentiation. Previously considered as females masculinized by an autosomal, masculinizing M gene (Rigaud & Juchault, 1993), we demonstrated for the first time that, in fact, three large DNA insertions of Wolbachia origin were integrated in their genome and consequently impaired the expression of genes responsible for male differentiation. The seventeen genes (more than 15.8 kb) inserted, induced genomic diversity and we noted that identified transposase coding genes had totally disappeared from these insertions. We discuss the putative roles of these unprecedented insertions in woodlice and make the inference that some woodlouse phenotypes are organisms that have been genetically modified in nature, and by natural causes.