Strain‐specific quantification of Wolbachia density in subtropical Argentinean Aedes albopictus: effects of tissue location and longevity

CHUCHUY, AILÉN; RODRIGUERO, MARCELA S.; MICIELI, M. VICTORIA

Frontiers in Insect Science

Frontiers

Año: 2025 vol. 5

The intracellular bacterium Wolbachia pipientis has emerged as a promising toolfor controlling mosquito-borne diseases; however, key aspects of its biologyremain insufficiently understood, particularly how Wolbachia influences vectorcompetence for certain arboviruses. Themain factors implicated are the activationof mosquito antiviral pathways and competition for cellular resources at the viralreplication site. Transinfection of Wolbachia strains into vector populations hasproven to be an effective strategy for controlling arboviral diseases. Here, weinvestigate the within-host density and tissue distribution of two naturallyoccurring Wolbachia strains—wAlbA and wAlbB—n Aedes albopictus fromArgentina, where infection patterns diverge from those observed globally. Usingquantitative PCR, we assessed symbiont density in ovarian (n = 5) and somatictissues (n = 5) of adult females, and in adult males across different ages: 0, 5 and 14days post-emergence (n = 5 per age group). Our results reveal superinfection inovaries (wAlbA + wAlbB) with similar densities (median relative densitywAlbA = 3.78andmedian relative densitywAlbB = 3.31), but only wAlbB was consistently detectedin somatic tissues (median relative densitywAlbB = 0.41), suggesting tissue-specificdistribution of strains. Additionally, wAlbB density in males remained stablethroughout the adult lifespan (median relative densityTime0 = 0.83; medianrelative densitytime 5 = 1.98; median relative densitytime 14 = 0.66). These findingssupport the hypothesis that Wolbachia somatic localization is strain-specific andmay be under evolutionary selection, with implications for vertical transmissionand host fitness. By advancing our understanding ofWolbachia density dynamics ina natural mosquito vector population, this study contributes critical baseline datato inform and optimize Wolbachia-based biocontrol strategies in regions at risk ofarboviral outbreaks. Because the wAlbB strain from Ae. albopictus is widely used inreplacement techniques, any knowledge of its behavior in natural host populationsis valuable.