Evolution of chemical defences in Salix

Chemical diversity of plant defences is a major driver of insect-plant interactions. Answering the question: Why is there such high diversity of chemical defences? is thus crucial for understanding key ecological processes that shape composition and diversity of insect-plant assemblages. Our aim is to unravel the mechanisms by which chemical diversity evolves. To achieve this, we use ecologically dominant and diverse willows as a model genus. We contrast chemical defences and herbivore communities of allopatric and sympatric willow species. This will show how the exposure to local pools of herbivores promotes the diversity of willow defences and leads to their divergent evolution.