Spodoptera exempta larvae were orally challenged with one of five doses of SpexNPV and survivors were mated and their offspring monitored for viral mortality. Offspring from parents challenged with low viral doses showed evidence of ‘immune priming’ (i.e. enhanced survival following SpexNPV challenge); in contrast, offspring from parents challenged with higher viral doses exhibited greater susceptibility to viral challenge.
Most offspring larvae died of the virus they were orally challenged with; in contrast, most offspring from parents that had been challenged with the highest doses were killed by the vertically transmitted virus (90%) and not the challenge virus.
These results demonstrate that the outcome of a potentially lethal viral challenge is critically dependent on the level of exposure to virus in the parental generation, either increasing resistance at very low parental viral doses (consistent with trans-generational immune priming) or increasing susceptibility at higher parental doses (consistent with virus triggering).
Wilson, K., Grzywacz, D., Cory, J.S., Donkersley, P. & Graham R.I. (2021) Trans-generational virus transmission and immune priming are dose-dependent. Journal of Animal Ecology 2021;00:1– 10.
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