ROOT DISTURBANCE OF COMMON ASH, FRAXINUS-EXCELSIOR (OLEACEAE), LEADS TO REDUCED FOLIAR TOUGHNESS AND INCREASED FEEDING BY A FOLIVOROUS WEEVIL, STEREONYCHUS-FRAXINI (COLEOPTERA, CURCULIONIDAE)

1. Bioassays were carried out to examine differences in the feeding of a folivorous weevil, Stereonychus fraxini De Geer, on leaves from ash saplings with undamaged roots, and those with damaged roots. Beetles ate significantly more of the leaves of root-damaged saplings in a cho ice experiment. 2. A separate study of the effect of root damage on le af toughness was carried out on a second group of ash saplings. Saplin gs with damaged roots had less tough leaves than control saplings. Dec reased leaf toughness in hypothesized as a mechanism to explain the pr eference of weevils for leaves from damaged trees. 3. Both chemical an d physical changes may occur in the tissues of ash trees in response t o environmental stress such as drought and root damage. 4. Root damage caused by agricultural disturbance is hypothesized as a mechanism mak ing mature ash trees in hedgerow ecosystems more susceptible to insect herbivores.