Calluna vulgaris volatile emissions suggest varying anti-herbivore defence strategies with plant ontogeny

Background Calluna vulgaris (heather) is native to Europe, where it dominates several plant communities, but is invasive in countries like Australia and New Zealand (NZ). In its native ranges, including the United Kingdom (UK), heather provides habitat to arthropods of several feeding guilds and recent studies in its invaded and native ranges show that this plant is a prolific producer of volatile organic compounds (VOCs). These defensive metabolites can modify the behaviours of neighbouring plant and insect species. However, differences in VOC emissions between growth stages (ontogeny) have not yet been explored.