title: Plant chemical defence: a partner control mechanism stabilising plant--seed-eating pollinator mutualisms.
abstract: BACKGROUND
  Mutualisms are inherently conflictual as one partner always benefits from reducing the costs imposed by the other. Despite the widespread recognition that mutualisms are essentially reciprocal exploitation, there are few documented examples of traits that limit the costs of mutualism. In plant/seed-eating pollinator interactions the only mechanisms reported so far are those specific to one particular system, such as the selective abortion of over-exploited fruits.
  
  
  RESULTS
  This study shows that plant chemical defence against developing larvae constitutes another partner sanction mechanism in nursery mutualisms. It documents the chemical defence used by globeflower Trollius europaeus L. (Ranunculaceae) against the seed-eating larvae of six pollinating species of the genus Chiastocheta Pokorny (Anthomyiidae). The correlative field study carried out shows that the severity of damage caused by Chiastocheta larvae to globeflower fruits is linked to the accumulation in the carpel walls of a C-glycosyl-flavone (adonivernith), which reduces the larval seed predation ability per damaged carpel. The different Chiastocheta species do not exploit the fruit in the same way and their interaction with the plant chemical defence is variable, both in terms of induction intensity and larval sensitivity to adonivernith.
  
  
  CONCLUSIONS
  Adonivernith accumulation and larval predation intensity appear to be both the reciprocal cause and effect. Adonivernith not only constitutes an effective chemical means of partner control, but may also play a key role in the sympatric diversification of the Chiastocheta genus.
authors.affiliation: Laboratoire d'Ecologie Alpine, UMR CNRS 5553, Université Joseph Fourier BP53, 38041 Grenoble Cedex 9, France. sebastien.ibanez@ujf-grenoble.fr
authors.forename: Sébastien
authors.initials: S
authors.lastname: Ibanez
authors.forename: Christiane
authors.initials: C
authors.lastname: Gallet
authors.forename: Fanny
authors.initials: F
authors.lastname: Dommanget
authors.forename: Laurence
authors.initials: L
authors.lastname: Després
mesh_terms: D000818:Animals; D004175:Diptera / Q000187:drug effects / Q000502:physiology*; D047309:Flavones; D005419:Flavonoids / Q000494:pharmacology*; D020387:Food Chain; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D054817:Pollination; D029626:Ranunculaceae / Q000737:chemistry* / Q000502:physiology*; D012639:Seeds / Q000737:chemistry / Q000502:physiology; D013559:Symbiosis / Q000187:drug effects
chemical_list: D047309:Flavones; D005419:Flavonoids; C043562:flavone