Data from: Species-specific plant-soil feedback effects on above-ground plant-insect interactions

1. Plant–soil feedback (PSF) effects on plant performance strongly depend
on the plant species that conditioned the soil. Recent studies have shown
that PSF can change above-ground plant–insect interactions via
soil-mediated changes in plant quality, but whether these effects depend
on species-specific soil conditioning is unknown. We examined how PSF
effects of several plant species influence above-ground plant–aphid
interactions. 2. We grew ragwort (Jacobaea vulgaris) in field soil
conditioned specifically by 10 plant species, belonging to three
functional groups (grasses, forbs and legumes), in a multispecies mixture
of the conditioned soils and in control (unconditioned) field soil. We
measured plant biomass, concentrations of primary (amino acids) and
secondary (pyrrolizidine alkaloids) metabolites in phloem exudates, and
performance of the generalist aphid Brachycaudus cardui and the specialist
Aphis jacobaeae. 3. We observed that plant species, via species-specific
effects on soil fungal communities, exerted unique plant–soil effects on
J. vulgaris biomass, amino acid concentrations in phloem exudates and
aphid performance. The direction and magnitude of the species-specific PSF
effects on aphid performance differed between both aphid species. PSF
effects on soil fungal communities, plant biomass and A. jacobaeae
performance also differed between grasses, forbs and legumes, with soil
conditioning by forbs resulting in lowest plant biomass and aphid
performance. 4. Synthesis. Our study provides novel evidence that PSF
effects on above-ground plant–insect interactions are highly species
specific. Our results add a new dimension to the rapidly developing
research fields of PSF and above-below-ground interactions, and highlights
that these fields are tightly linked.