Wolbachia pipientis: Microbial manipulator of arthropod reproduction

The alpha-proteobacterium Wolbachia pipientis is a very common cytoplasmic symbiont of insects, crustaceans, mites, and filarial nematodes. To enhance its transmission, W. pipientis has evolved a large scale of host manipulat ions: parthenogenesis induction, feminization, and male killing. W. pipient is's most common effect is a crossing incompatibility between infected male s and uninfected females. Little is known about the genetics and biochemist ry of these symbionts because of their fastidious requirements. The affinit y of W. pipientis for the microtubules associated with the early divisions in eggs may explain some of their effects. Such inherited microorganisms ar e thought to have been major factors in the evolution of sex determination, eusociality, and speciation. W. pipientis isolates are also of interest as vectors for the modification of wild insect populations, in the improvemen t of parasitoid wasps in biological pest control, and as a new method for i nterfering with diseases caused by filarial nematodes.