Parasite-Induced Replacement of Host Microbiota: Impact of Xenos gadagkari Parasitization on the Microbiota of Polistes wattii

The study of microbiota of social insects under different ecological conditions can provide important insights into the role of microbes in their biology and behavior. Polistes is one of the most widely distributed and extensively studied genera of social wasps, yet a comprehensive study on the microbiota of any species of Polistes or any primitively eusocial wasp is missing. Polistes wattii is an Asian wasp, which hibernates in winter and exhibits a biannual nest founding strategy. It is often parasitized by the strepsipteran endoparasite/parasitoid Xenos gadagkari, which changes the morpho-physiology and behavior of their hosts. In this study, we employ 16S rRNA amplicon sequencing, using the Oxford Nanopore platform, to study the microbial community of P. wattii and investigate the effects of seasonality, sex, and Xenos parasitism. We show that the microbiota differs in females from solitary foundress spring nests and multiple foundress summer nests. The microbiota also differs in males and females. Finally, we show that X. gadagkari parasitism replaces and homogenizes the microbiota of P. wattii. Unlike the unparasitized wasps, the microbiota of X. gadagkari parasitoids and parasitized wasps are dominated by Wolbachia and Providencia. Although the normal microbiota of P. wattii resembles that of highly eusocial vespid wasps, we show that the microbiota of parasitized P. wattii becomes more like the microbiota of strepsipterans. Therefore, it appears that X. gadagkari and other such strepsipteran parasitoids may have a bigger impact on the biology of their hosts than previously thought.