Effects of soil biota community (SB, SEG 33 and SEG 37), <i>Agriotes</i> training (AP1, <i>Agriotes</i> presence in phase 1, untrained and trained) and <i>Agriotes</i> presence (AP2, without and with) on plant and AMF parameters in phase 2.

<p>significance level:</p>*<p>p<0.05,</p>**<p>p<0.01,</p>***<p>p<0.001,</p><p>ns = not significant, LEH: length of extraradical AMF hyphae, AMF: arbuscular mycorrhizal fungi.</p

Plant and AMF parameters and Soil CN ratio (mean (se)) in different soil treatments (soil biota communities SGE 33 and SEG 37, <i>Agriotes</i> untrained (−AP1) or trained (+AP1) soil substrate) in phase 1 and 2.

<p>gDW: gram dry weight, LEH: length of extraradical AMF hyphae, AMF: arbuscular mycorrhizal fungi, RLC: root length colonized.</p

Shoot biomass (mean + se) of plants affected by the presence of <i>Agriotes</i> larvae.

<p>Phase 1 (A) <i>P. lanceolata</i> (B) <i>A. millefolium</i>; phase 2 (C) <i>P. lanceolata</i> (D) <i>A. millefolium</i>, (E) <i>T repens;</i> SEG33, SEG37: soil biota from respective grassland sites; −AP1, +AP1: untrained and <i>Agriotes</i> trained soil from phase 1, respectively.</p

The Root Herbivore History of the Soil Affects the Productivity of a Grassland Plant Community and Determines Plant Response to New Root Herbivore Attack

<div><p>Insect root herbivores can alter plant community structure by affecting the competitive ability of single plants. However, their effects can be modified by the soil environment. Root herbivory itself may induce changes in the soil biota community, and it has recently been shown that these changes can affect plant growth in a subsequent season or plant generation. However, so far it is not known whether these root herbivore history effects (i) are detectable at the plant community level and/or (ii) also determine plant species and plant community responses to new root herbivore attack. The present greenhouse study determined root herbivore history effects of click beetle larvae (Elateridae, Coleoptera, genus <i>Agriotes</i>) in a model grassland plant community consisting of six common species (<i>Achillea millefolium</i>, <i>Plantago lanceolata</i>, <i>Taraxacum officinale</i>, <i>Holcus lanatus</i>, <i>Poa pratensis</i>, <i>Trifolium repens</i>). Root herbivore history effects were generated in a first phase of the experiment by growing the plant community in soil with or without <i>Agriotes</i> larvae, and investigated in a second phase by growing it again in the soils that were either <i>Agriotes</i> trained or not. The root herbivore history of the soil affected plant community productivity (but not composition), with communities growing in root herbivore trained soil producing more biomass than those growing in untrained soil. Additionally, it influenced the response of certain plant species to new root herbivore attack. Effects may partly be explained by herbivore-induced shifts in the community of arbuscular mycorrhizal fungi. The root herbivore history of the soil proved to be a stronger driver of plant growth on the community level than an actual root herbivore attack which did not affect plant community parameters. History effects have to be taken into account when predicting the impact of root herbivores on grasslands.</p> </div

Effects of soil biota community (SB, SEG 33 and SEG 37) and <i>Agriotes</i> presence (AP1, without and with) on plant and AMF parameters and soil CN in phase 1.

<p>significance level:</p>*<p>p<0.05,</p>**<p>p<0.01,</p>***<p>p<0.001,</p><p>ns = not significant, LEH: length of extraradical AMF hyphae, AMF: arbuscular mycorrhizal fungi.</p