Wolbachia is a naturally-occurring, intracellular, bacteria found in over half of all insect species worldwide. This includes insects, spiders, and other invertebrates such as crustaceans and nematodes. In Hawaiʻi, Wolbachia is already present in many native and non-native insects, including mosquitoes.
Wolbachia is known to have a high degree of host specialization, meaning that different strains of the bacteria are typically associated with specific host species or groups of related host species.
Wolbachia (in green) within the ovaries of a mosquito.
Zhiyong Xi/ Michigan State University
Wolbachia can manipulate the reproductive systems of their hosts in ways that benefit the bacteria’s transmission. For example, some strains of Wolbachia can cause their hosts to produce only female offspring. Other strains can induce Cytoplasmic Incompatibility, which means the males and females can’t reproduce successfully if they carry different, incompatible strains of Wolbachia.
Male mosquitoes with one strain of Wolbachia can only successfully reproduce with females with a compatible strain of Wolbachia. Males with one strain of Wolbachia cannot successfully reproduce with females with an incompatible strain of Wolbachia.
This is the phenomenon that the Birds, Not Mosquitoes partnership is using through the Incompatible Insect Technique (IIT) for mosquito suppression in Hawaiʻi.