Defense of Scots pine against sawfly eggs (Diprion pini) is primed by exposure to sawfly sex pheromones

Research output: Contribution to journalArticle


Plants respond to insect infestation with defenses targeting insect eggs on their leaves and the feeding insects. Upon perceiving cues indicating imminent herbivory, such as damage-induced leaf odors emitted by neighboring plants, they are able to prime their defenses against feeding insects. Yet it remains unknown whether plants can amplify their defenses against insect eggs by responding to cues indicating imminent egg deposition. Here, we tested the hypothesis that a plant strengthens its defenses against insect eggs by responding to insect sex pheromones. Our study shows that preexposure of Pinus sylvestris to pine sawfly sex pheromones reduces the survival rate of subsequently laid sawfly eggs. Exposure to pheromones does not significantly affect the pine needle water content, but results in increased needle hydrogen peroxide concentrations and increased expression of defense-related pine genes such as SOD (superoxide dismutase), LOX (lipoxygenase), PAL (phenylalanine ammonia lyase), and PR-1 (pathogenesis related protein 1) after egg deposition. These results support our hypothesis that plant responses to sex pheromones emitted by an herbivorous insect can boost plant defensive responses to insect egg deposition, thus highlighting the ability of a plant to mobilize its defenses very early against an initial phase of insect attack, the egg deposition.


  • Norbert Bittner
  • Janik Hundacker
  • Ander Achotegui-Castells
  • Olle Anderbrant
  • Monika Hilker
External organisations
  • Free University of Berlin
  • Centre for Ecological Research and Forestry (CERAF)
  • Autonomous University of Barcelona
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biochemistry and Molecular Biology
  • Ecology


  • Diprion pini, hydrogen peroxide, induced plant defense, insect oviposition, priming
Original languageEnglish
Pages (from-to)24668-24675
Number of pages8
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number49
Publication statusPublished - 2019
Publication categoryResearch

Related projects

Erling Jirle & Olle Anderbrant


Project: Research

View all (1)