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Chemoecology

, Volume 17, Issue 4, pp 235–243 | Cite as

Constitutive or induced defences - how does Eucalyptus globulus defend itself from larval feeding?

  • Luke P. RapleyEmail author
  • Geoff R. Allen
  • Brad M. Potts
  • Noel W. Davies
Article

Summary.

Following herbivory, induced responses involving plant secondary metabolites have been reported in a number of tree species. Although a wide range of plant secondary metabolites appear to operate as constitutive plant defences in trees belonging to the Eucalyptus genus, no induced responses have as yet been reported following foliar-chewing insect damage. We empirically tested whether branch defoliation (artificial and larval) of 2-year-old Eucalyptus globulus Labill. trees altered the abundance of specific plant secondary metabolites immediately (3 months after initial larval feeding) and 8 months after the cessation of larval feeding. Metabolites assayed, included essential oils, polyphenolic groups and foliar wax compounds and in all cases their abundance was not significantly altered by defoliation. However, the level of foliar tannins after 3 months of larval feeding did display a trend that suggested elevated levels as the result of defoliation, though this trend was not evident 8 months later, indicating that, if real, the response was a rapid and not a delayed induced response. The level of foliar tannins was also negatively correlated to both average larval survival and average percentage branch defoliation, suggesting that foliar tannins may operate as toxins and/or anti-feedants to M. privata larval feeding.

Keywords.

Plant-insect interactions leaf chemistry induced and constitutive plant defences Lepidoptera Geometridae Mnesampela privata Myrtaceae Eucalyptus globulus 

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Copyright information

© Birkhaeuser 2007

Authors and Affiliations

  • Luke P. Rapley
    • 1
    • 4
    • 5
    Email author
  • Geoff R. Allen
    • 1
    • 5
  • Brad M. Potts
    • 2
    • 5
  • Noel W. Davies
    • 3
    • 5
  1. 1.School of Agricultural Science/TIARUniversity of TasmaniaHobartAustralia
  2. 2.School of Plant ScienceUniversity of TasmaniaHobartAustralia
  3. 3.Central Science LaboratoryUniversity of TasmaniaHobartAustralia
  4. 4.School of Public Health, Tropical Medicine and Rehabilitation SciencesJames Cook UniversityCairnsAustralia
  5. 5.Cooperative Research Centre for ForestryHobartAustralia

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