Root disturbance of common ash, Fraxinus excelsior (Oleaceae), leads to reduced foliar toughness and increased feeding by a folivorous weevil, Stereonychus fraxini (Coleoptera, Curculionidae)

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Abstract

Abstract.

  • 1Bioassays 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 choice experiment.
  • 2A separate study of the effect of root damage on leaf toughness was carried out on a second group of ash saplings. Saplings with damaged roots had less tough leaves than control saplings. Decreased leaf toughness in hypothesized as a mechanism to explain the preference of weevils for leaves from damaged trees.
  • 3Both chemical and physical changes may occur in the tissues of ash trees in response to environmental stress such as drought and root damage.
  • 4Root damage caused by agricultural disturbance is hypothesized as a mechanism making mature ash trees in hedgerow ecosystems more susceptible to insect herbivores.

Ancillary