Trans‐generational viral transmission and immune priming are dose‐dependent

It is becoming increasingly apparent that trans-generational immune priming (i.e. the transfer of parental immunological experience to its progeny resulting in offspring protection from pathogens persist across generations) a common phenomenon not only vertebrates, but also invertebrates. Likewise, it known covert pathogenic infections may become ‘triggered’ into an overt infection by various stimuli, including exposure heterologous infections. Yet, rarely have both phenomena been explored parallel. Using as model system African armyworm Spodoptera exempta, eruptive agricultural pest and endemic dsDNA virus (Spodoptera exempta nucleopolyhedrovirus, SpexNPV), aim this study was explore impact inoculating-dose on pathogen transmission (in broadest sense). Larvae were orally challenged with one five doses SpexNPV survivors these treatments mated their monitored for viral mortality. Offspring parents low showed evidence ‘immune priming’ enhanced survival following challenge); contrast, higher exhibited greater susceptibility challenge. Most larvae died they with; most had highest killed vertically transmitted (90%) challenge virus. These results demonstrate outcome potentially lethal critically dependent level generation—either increasing resistance at very (consistent priming) or triggering). We discuss implications findings understanding natural epizootics baculoviruses using them biological control agents.