Induced Volatile Chemistry and Arthropod Predation Across a Tree Diversity Gradient.

In Quercus petraea, methyl jasmonate induction strongly reshaped VOC profiles, and tree species richness modulated sesquiterpene composition during the first sampling period.

• Why it matters: Surrounding tree diversity may tune forest tree defence and multitrophic interactions, but how it alters induced volatile chemistry and predator responses is unclear.
• What they did: In a biodiversity-ecosystem functioning experiment, branches were repeatedly induced with methyl jasmonate; VOCs were collected after the first and last induction rounds using PDMS tubes and analyzed by TD-GC-MS, while predation was measured with plasticine caterpillars.
• The result: β-Ocimene was negatively associated with predation probability during the second sampling period, whereas absolute VOC class emissions and broad class-level composition showed no clear, consistent explanation of predation variation.