Susanne Wurst1, Dereje Dugassa-Gobena2, Reinhard Langel3, Michael Bonkowski1, Stefan Scheu1. 1. Technische Universität Darmstadt, Institut für Zoologie, Schnittspahnstr. 3, 64287 Darmstadt, Germany. 2. Georg-August Universität Göttingen, Institut für Pflanzenpathologie und Pflanzenschutz, Grisebachstr. 6, 37077 Göttingen, Germany. 3. Georg-August Universität Göttingen, Kompetenzzentrum Stabile Isotope, Forschungszentrum Waldökosysteme, Büsgenweg 2, 37077 Göttingen, Germany.
Abstract
• Vesicular-arbuscular mycorrhiza (VAM) and earthworms are known to affect plant and herbivore performance. However, surprisingly few studies have investigated their interactions. • In a glasshouse experiment we investigated the effects of earthworms (Aporrectodea caliginosa) and VAM (Glomus intraradices) on the growth and chemistry of Plantago lanceolata and the performance of aphids (Myzus persicae). • Earthworms did not affect VAM root colonization. Earthworms enhanced shoot biomass, and VAM reduced root biomass. VAM increased plant phosphorus content, but reduced the total amount of N in leaves. Earthworms led to a preferential uptake of soil N compared with 15 N from the added grass residues in the absence of VAM. Earthworm presence reduced the concentration of catalpol. Earthworms and VAM combined accelerated the development of M. persicae, while the development tended to be delayed when only VAM or earthworms were present. • We suggest that earthworms promote plant growth by enhancing soil N availability and may affect herbivores by influencing concentrations of secondary metabolites. VAM enhances the P uptake of plants, but presumably competes with plant roots for N.
• Vesicular-arbuscular mycorrhiza (n class="Chemical">VAM) and n class="Species">earthworms are known to affect plant and herbivore performance. However, surprisingly few studies have investigated their interactions. • In a glasshouse experiment we investigated the effects of earthworms (Aporrectodea caliginosa) and VAM (Glomus intraradices) on the growth and chemistry of Plantago lanceolata and the performance of aphids (Myzus persicae). • Earthworms did not affect VAM root colonization. Earthworms enhanced shoot biomass, and VAM reduced root biomass. VAM increased plant phosphorus content, but reduced the total amount of N in leaves. Earthworms led to a preferential uptake of soil N compared with 15 N from the added grass residues in the absence of VAM. Earthworm presence reduced the concentration of catalpol. Earthworms and VAM combined accelerated the development of M. persicae, while the development tended to be delayed when only VAM or earthworms were present. • We suggest that earthworms promote plant growth by enhancing soil N availability and may affect herbivores by influencing concentrations of secondary metabolites. VAM enhances the P uptake of plants, but presumably competes with plant roots for N.