Transgenerational effects are often assumed to have adaptive value as a driver of variation in offspring and parental fitness. Studies of transgenerational effects often focus on single environmental variables. However, in nature, it is unlikely for one factor to vary independently from others and there are likely to be trade-offs between different stressors. We altered the nutritional environment of both parents and offspring to examine how nutritional stress influences transgenerational immune priming (TGIP) with a sublethal challenge by the bacterial pathogen Bacillus thuringiensis, in the cabbage looper, Trichoplusia ni. Transgenerational immune priming was adaptive when offspring encountered the same pathogen experienced by their parents, such that offspring resistance to B. thuringiensis increased 1·5-fold and antibacterial activity in the haemolymph increased by as much as 4-fold. However, this was not a general increase in pathogen resistance as susceptibility to a second pathogen, the baculovirus, TnSNPV remained the same. Interestingly, nutritional stress in the parents both enhanced nutritional stress tolerance of offspring and heightened resistance to both B. thuringiensis and TnSNPV. Elevated pathogen resistance was linked to increased egg size. There was a significant trade-off between TGIP and the transfer of nutritional stress tolerance when parents encountered both stressors simultaneously, such that parents transferred resistance to pathogens but not nutritional stress tolerance. These results highlight the trade-offs that can modulate the occurrence and magnitude of transgenerational effects and illustrate the importance of assessing interactions between multiple environmental variables. At high population densities, disease risk increases and resour-ces become depleted. Thus, our findings could have significant implications for population dynamics.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics