Wolbachia transinfections in Culex quinquefasciatus generate cytoplasmic incompatibility

Culex quinquefasciatus is an important mosquito vector of a number of viral and protozoan pathogens of humans and animals, and naturally carries the endosymbiont Wolbachia pipientis , strain w Pip. Wolbachia are used in two distinct vector control strategies: firstly, population suppression caused by mating incompatibilities between mass‐released transinfected males and wild females; and secondly, the spread of pathogen transmission‐blocking strains through populations. Using embryonic microinjection, two novel Wolbachia transinfections were generated in C. quinquefasciatus using strains native to the mosquito Aedes albopictus : a w AlbB single infection, and a w Pip plus w AlbA superinfection. The w AlbB infection showed full bidirectional cytoplasmic incompatibility (CI) with wild‐type C. quinquefasciatus in reciprocal crosses. The w Pip w AlbA superinfection showed complete unidirectional CI, and therefore population invasion potential. Whereas the w AlbB strain showed comparatively low overall densities, similar to the native w Pip, the w Pip w AlbA superinfection reached over 400‐fold higher densities in the salivary glands compared to the native w Pip, suggesting it may be a candidate for pathogen transmission blocking.