Data from: Interspecific plant competition mediates the metabolic and ecological signature of a plant-herbivore interaction under warming and elevated CO2

1. Biotic interactions shape community evolution, but we lack mechanistic
insights on how metabolic and ecological processes under climate change
are altered by biotic interactions. 2. We used a two-trophic model
community consisting of the aphid Dysaphis plantaginea feeding on the forb
Plantago lanceolata, and a grass competitor Lolium perenne that does not
experience herbivory by the aphid. Monocultures and mixtures were exposed
to the herbivory treatment and to three relevant simulated environmental
changes as prevalent under current climate change (increased temperature,
CO2, and increased temperature and CO2) 3. Elevated CO2 reduced the
nitrogen content of P. lanceolata, while simultaneous increases of CO2 and
temperature modified the plant metabolic component and the magnitude of
these responses in different directions. Elevated CO2 enhanced defence
systems in P. lanceolata, but these effects were not altered by warming.
Interspecific plant competition did, however, neutralise these responses.
There were no indirect effects of climate change on aphid population
growth despite changes in plant defense, nutritional quality and biomass
induced by our environmental change scenarios. 4. We thus demonstrate
interactions between abiotic and biotic processes on plant metabolite
profiles, but more importantly, that climate change effect on a selection
of the metabolic pathways are altered by herbivory and competition. Our
experiment under semi-natural conditions thus demonstrates the
non-additive and often neutralizing effects of biotic interactions on
plant metabolism and species performance under climate-associated
environmental change.