Two promising candidates for paratransgenesis, Elizabethkingia and Asaia, increase in both sexes of Anopheles gambiae s.l mosquitoes after feeding

Abstract

Abstract Background The discovery of high prevalence of Microsporidia MB in both sexes of Anopheles has informed the need to also include male mosquitoes in the study of mosquito-associated microbiome which had mainly been female-focused. In this study, the microbiota of male and female Anopheles gambiae s.l were compared to identify similarity or otherwise of bacterial composition between the two sexes. Methods Late larval instars of Anopheles mosquitoes were collected from the field and raised to adults. Equal numbers of males and females of 1-day-old non-sugar-fed, 4–5-day old sugar-fed and post blood-fed females were randomly selected for whole body analyses of bacteria 16S rRNA. Results Results reveal that male and female mosquitoes generally share similar microbiota except when females are blood fed. Compared to newly emerged unfed mosquitoes, having sugar and/or blood meal increased dissimilarity in microbial diversity in both males and females with the variation being greater among females (39% P = 0.01) than in males (29% P = 0.03). Elizabethkingia meningoseptica and Asaia siamensis were highly abundant bacteria species (> 0.01 average relative abundance) that were common significant discriminants between groups based on their feeding status. E. meningoseptica was shown to be the only common differentially significant bacteria in male and female mosquitoes that had fed compared to their unfed counterparts (LDA score > 4.0, P < 0.05). Its relative abundance did not change in blood fed females while A. siamensis reduced. In males, however, A. siamensis did not differ significantly post sugar meal. Conclusions Our results indicate the opportunities for stable infection in mosquitoes should these promising species be used in bacteria-mediated disease control. Further studies are recommended for clearer understanding of multiple strain tissue tropism for selecting most appropriate and effective transmission blocking strategies.