Wolbachia

Definition

A genus of gram-negative, intracellular Alphaproteobacteria (family Anaplasmataceae) that infects arthropods and filarial nematodes as maternally transmitted endosymbionts. The relationship with hosts spans parasitism, commensalism, and obligate mutualism; many strains manipulate host reproduction through cytoplasmic incompatibility, feminization of males, parthenogenesis induction, or male killing. Wolbachia is among the most widespread reproductive parasites in the biosphere, estimated to infect 25–70% of insect species, and has become a tool for biocontrol and vector suppression programs.

Etymology

Named for Simeon Burt Wolbach (1880–1954), American pathologist who co-discovered the bacterium in 1924, with the Latin feminine suffix -ia.

Example

In Culex mosquitoes, Wolbachia strain wAlbB induces cytoplasmic incompatibility: matings between infected males and uninfected females produce unviable embryos, while infected females can reproduce successfully with any male, driving the bacterium rapidly through host populations.

Related Terms

• Cytoplasmic incompatibility
• endosymbiont
• maternal transmission
• parthenogenesis induction
• male killing
• Rickettsiales
• vector control
• Biological control

Usage Notes

Specialists often refer to specific strains (e.g., wMel, wRi, wAlbB) rather than the genus alone. The term is sometimes loosely applied to the bacterium in any host, though phylogenetic studies recognize multiple supergroups (A–Q) with distinct host ranges. Not all Wolbachia infections are parasitic: in some filarial nematodes and bed bugs, the bacterium is an obligate mutualist required for host fertility or nutrient provisioning. Distinguish from other reproductive manipulators such as Cardinium, Spiroplasma, and Rickettsia.