Indirect effects (or parental effects) occur when thermal conditions met by a host parental generation affect the way its offspring will interact with parasitoids.  Using the complex involving eggs of the moth Lobesia botrana as hosts for the parasitoid Trichogramma cacoeciae, we developed an experimental design to disentangle the effects of (1) host parental temperature (temperature at which the host parental generation developed and laid host eggs) and (2) host offspring temperature (temperature at which host eggs were incubated following parasitism, i.e. direct thermal effects) on this interaction.  Such indirect thermal effects might arise from a low nutritional quality and/or a high immunity of host eggs laid in warm conditions.  By contrast with host parental temperature, offspring temperature (direct thermal effects) did not significantly affect the outcomes of the interaction.  This work emphasises the importance of accounting for parental thermal effects to predict the future of trophic dynamics under global warming scenarios.
THERM