title: A case study of modified interactions with symbionts in a hybrid mediterranean orchid.
abstract: OBJECTIVE
  Most studies on orchid hybrids examine separately the effects of hybridization on interactions with pollinators or with mycorrhizal fungi. Here, we simultaneously investigated both interactions in the mediterranean food-deceptive Orchis simia, O. anthropophora, and their hybrid (O. ×bergonii) and tested a possible breakdown of coevolution using a multidisciplinary approach. •
  
  
  METHODS
  We compared leaf growth, seed viability, emitted scent, and mycorrhizal fungi (species and rate of infection) among these three taxa. •
  
  
  RESULTS
  We show that leaf surface is greater in adult hybrids than in the parental species, suggesting a heterosis effect for vegetative growth. We demonstrate that flowers of the two parental species emit well-differentiated bouquets of volatile organic compounds, while hybrids emit larger quantities, accumulating most compounds of the two parental species. However, hybrids fail to attract pollinators and have a 10 times lower fruit set. We determined that closely related Tulasnellales are mycorrhizal in the three taxa, suggesting that the mycorrhizal partner does not impair hybrid survival. We propose an interpretative model for O. ×bergonii compared with its parents. •
  
  
  CONCLUSIONS
  In hybrids, carbon resources normally devoted to reproduction may be reallocated to the mycorrhizal symbiosis as a result of the disruption of the pollination interaction in hybrids. Higher mycorrhizal infection may in turn enhance vegetative growth and scent emission. Such interplay between the two obligate biotic interactions yields new insights into hybridization among orchids.
authors: Equipe Interactions Biotiques, Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, 1919 route de Mende, F-34293 Montpellier Cedex 5, France.
authors: Bertrand
authors: B
authors: Schatz
authors: Alexandre
authors: A
authors: Geoffroy
authors: Benjamin
authors: B
authors: Dainat
authors: Jean-Marie
authors: JM
authors: Bessière
authors: Bruno
authors: B
authors: Buatois
authors: Martine
authors: M
authors: Hossaert-McKey
authors: Marc-André
authors: MA
authors: Selosse