Novel Pathogen Infections in the Clonal Raider Ant

Abstract

Social insects live in high-density colonies of genetically similar individuals making them susceptible to rapid pathogen transmission. While pathogens can have detrimental effects on host fitness, insect hosts employ various immune strategies in response to infection. Here we study host-pathogen interaction and transmission dynamics in the clonal raider ant, Ooceraea biroi, using the acute bee paralysis virus (ABPV) and Sodalis praecaptivus. We investigate the ability of these pathogens to replicate and transmit within host colonies and their impact on survival. To understand the host response, we investigate potential immune mechanisms. Our results indicate that ABPV does not infect or elicit an RNAi response in O. biroi. In contrast, S. praecaptivus successfully establishes infection across multiple life stages. S. praecaptivus localizes across the host body and impacts survival and fecundity. It also leads to changes in host melanization. However, neither pathogen exhibits transmission among colonymates. Together our findings contribute towards understanding infection dynamics in response to novel pathogens in O. biroi. These results also lay the groundwork for establishing a fluorescently tractable host-pathogen system in O. biroi that can be used for monitoring behaviour responses to infection progression within a colony.