From the leaf to the community: distinct dimensions of phytochemical diversity shape plant-insect interactions within and among individual plants

Plant secondary chemistry is known to be an important driver of plant-insect community structure across ecological scales. Recently, the concept of phytochemical diversity has been introduced to help describe variation in plant secondary chemistry and explain how this variation affects community structure. Previous studies show that phytochemical diversity among individuals and species results in phytochemical mosaics, known as the phytochemical landscape. However, plant traits can vary at finer scales, such as within individuals, and even a single host plant may be perceived as an entire phytochemical landscape by an interacting insect.

Using the neotropical shrub Piper amalago, we tested and compared how herbivory, caterpillar biodiversity and plant-herbivore network structure are affected by the compositional (number and concentration of compounds) and structural (diversity of distinct chemical structures) dimensions of phytochemical diversity. We analysed variation among individu...