Legacy effects of herbivory enhance performance and resistance of progeny plants

Abstract

1. Herbivory‐induced changes in plant resistance and tolerance traits can mediatethe interaction between spatially and temporally separated above‐ and below‐ground herbivores. However, it is unknown how long the impact of transient her‐bivory events last or if legacy effects can be detected systemically in the plant andacross plant generations.
2. Here, we studied the impact of transient above‐ground herbivory by the specialistcaterpillar Manduca sexta on the plant traits of wild tobacco Nicotiana attenuataand the consequences for below‐ground root‐knot nematodes Meloidogyne incog‐nita in short‐term, long‐term, and transgenerational experiments.
3. In the short‐ and long‐term experiments, above‐ and below‐ground herbivory hadsignificant, albeit independent, impacts on key plant traits such as plant biomass,nutrient content, and secondary metabolites. In addition, herbivory influenced fit‐ness parameters such as seed yield and quality. In the long‐term and transgenera‐tional experiments, transient above‐ground herbivory had facilitating effects onnematodes, irrespective of any treatments of the parental plants. We found evi‐dence for transgenerational legacy effects of both above‐ and below‐ground her‐bivory on the resistance of progeny plants against above‐ground herbivores.Additionally, below‐ground herbivory in the parental generation increased theroot biomass of progeny plants.
4. Synthesis. Our results suggest that herbivory may have a long‐term impact onplant fitness by improving the performance of progeny plants challenged byabove‐ and below‐ground herbivory.