Background and aims – The aim of this study was to investigate the potential ecological significance of wind mediated leaf movement because it has recently been suggested that leaf movement may deter herbivory and produce a selective advantage. Methods – Direct observations were made of the levels of invertebrate herbivore damage on leaves of different mobility. The Biological Records Centre database was used to compare the invertebrate communities associated with tree species that have contrasting leaf mobility. Finally simple field and laboratory experiments were performed to investigate the likely effect of leaf form and mobility on invertebrates' ability to adhere to them. Key results – Plants with more mobile leaves were found to suffer less herbivore damage, support fewer species of invertebrates, including proportionally more leaf miners and fewer surface grazers. The field experiment demonstrated that extreme leaf movements were effective at deterring external feeding phytophagous invertebrates and that the leaves of Quercus petraea appears adapted to facilitate greater movement that is an effective grazing deterrent. The laboratory experiment also supported this. Conclusions – Field observation, biological records and experiments combine to suggest that petiole length and hence mobility appear to explain highly significant differences in the invertebrate communities associated with closely related and functionally similar species of plants. It is argued that enhanced leaf mobility may be a deployed as a grazing deterrent by at least one third of native British trees and that selection in favour of enhanced leaf mobility, to deter herbivores may be balanced by selection to reduce leaf movement and direct wind damage.

GRAZING DETERRENT; HERBIVORY; LEAF DAMAGE; LEAF MOVEMENT; PHYTOPHAGOUS INVERTEBRATES