Trees emit scents when attacked by herbivores. They use these to attract predatory insects and even birds, thus getting rid of their pests. This had only been demonstrated in smaller-scale experiments so far. A team of researchers led by the German Centre for Integrative Biodiversity Research (iDiv), the Friedrich Schiller University Jena and Leipzig University have now demonstrated this phenomenon for the first time in a natural habitat – the canopy of the Leipzig floodplain forest. The chemical calls for help even significantly determine the composition of the insect community in the canopy. This knowledge could be used for future natural pest control in agriculture and forestry.