Native Wolbachia infection dynamics across Aedes albopictus (Diptera: Culicidae) populations in Hawaiʻi

Aedes albopictus , an important vector of arboviruses, such as dengue, chikungunya, and Zika, is a widespread invasive mosquito species in the Pacific Islands Countries and Territories, including Hawaiʻi. Wolbachia , an endosymbiotic bacterium, widely used for mosquito control through its cytoplasmic incompatibility and pathogen blocking properties. Two Wolbachia strains, w AlbA and w AlbB, naturally inhabit Aedes albopictus unlike Aedes aegypti . However, their infection patterns in Hawaiʻi remain poorly characterized and may influence the success of future Wolbachia -based control efforts. Using quantitative PCR, we characterized the Wolbachia infection status of Ae. albopictus collected from two Hawaiian Islands: Oʻahu and the Island of Hawaiʻi. We assessed the influence of sex, island, temperature, and precipitation on the prevalence and density of w AlbA and w AlbB, as well as interactions between the two strains. Overall, 98.5% ( N = 399) of individuals were infected with Wolbachia . All infected specimens carried w AlbB, but only 28.6% were superinfected with w AlbA. Infection dynamics were strongly sex-specific, with females significantly more likely to harbor w AlbA, and Wolbachia density was also significantly higher in females. The prevalence of w AlbA was associated with island and precipitation at the collection site. However, w AlbB prevalence did not vary significantly with sex, island, or climatic variables. In superinfected individuals, w AlbB consistently exhibited higher density than w AlbA, while w AlbB density was higher in superinfected individuals than in those with w AlbB mono-infection. Interestingly, both strains showed higher densities in females than in males. Strain densities were positively correlated in females but not in males, indicating sex-specific interactions. By characterizing the Wolbachia infection dynamics of Ae. albopictus populations in Hawaiʻi, these findings establish an important baseline for biocontrol efforts. We demonstrate that Ae. albopictus mosquitoes in Hawaiʻi were either superinfected or carry only w AlbB, with lower-than-expected w AlbA infection, which may complicate the design and effectiveness of Wolbachia -based control strategies. Our results highlight that future population suppression projects involving Wolbachia and cytoplasmic incompatibility in Hawai’i must take into account varying patterns of Wolbachia infection in the region prior to biocontrol strategy development and implementation.