THE TRANSFER OF WOLBACHIA-PIPIENTIS AND REPRODUCTIVE INCOMPATIBILITY BETWEEN INFECTED AND UNINFECTED STRAINS OF THE FLOUR BEETLE, TRIBOLIUM-CONFUSUM, BY MICROINJECTION

We report a protocol for transferring the cytoplasmic endosymbiont Wolbachia pipientis from infected to uninfected hosts in the flour beetle, Tribolium confusum, by microinjection of cytoplasm from infected donor eggs into uninfected host eggs. Postinjection survivorship was limited by the halocarbon oil, which was lethal to hatching larvae but necessary to stem the backflow of cytoplasm out of injected eggs. In test crosses, approximately 39% of surviving and maturing larvae exhibited the complete reproductive incompatibility typically associated with W. pipientis in this species. However, some transfected females failed to transmit the W. pipientis to their progeny and the incompatibility could be lost in the generation following transfection. Conversely, in some cases, females that did not themselves exhibit the incompatibility had some offspring that did exhibit partial incompatibilities.