Ultrastructural evidence of Wolbachia rickettsiales in Drosophila simulans and their relationships with unidirectional cross-incompatibility

Abstract TEM examination of two unidirectional cross-incompatible strains of Drosophila simulans (C compatible and P incompatible strains) showed intracellular procaryotes in the ovaries of the C strain and of the F1 offspring of the ♀C × ♂P crossing. Ovaries of the P strain and of the rare offspring of the ♀P × ♂C crossing were procaryote-free. These procaryotes seemed to be very similar to the rickettsia Wolbachia pipientis already described in mosquitoes. Their possible role in the cross-incompatibility is discussed.