Fungal mimicry and its consequences in the unique deceptive pollination of Dracula orchids
Mushroom mimicry is a bizarre example of a deceptive pollination strategy that exploits an intimate relationship between fungi and insects. This project explores the ecology and evolution of this phenomenon in the best-known group of fungal mimics: Dracula orchids.
The labellum of Dracula chestertonii has a remarkable resemblance to gilled mushrooms. (Photo: Bryn Dentinger)
Over 150 described species of Dracula orchids exist in the Neotropical cloud forests from Mexico to Peru and most appear to mimic fleshy mushrooms, using both visual and fragrance cues to deceive mushroom-seeking flies into acting as pollinators. Previous reports of this phenomenon have assumed that these plants are mimics of mushrooms, but they have not tested the key component of mimicry: that the resemblance is adaptive. This project will test the mushroom mimicry hypothesis in natural populations of Dracula in Ecuador by using field experiments, chemical analysis of flower and mushroom fragrances, and molecular tools to examine the specificity and reproductive consequences of the orchids’ resemblance to fungi. Our experimental strategies include studies of the relative roles of visual and olfactory cues in the deception of pollinating flies, manipulation of environmental context to assess the effect of model proximity on orchid fitness, as well as molecular identification of pollinia attached to insects caught around mushrooms. We also plan to analyze Dracula population genetics to infer realized reproductive consequences of mimicry and to use DNA barcoding techniques to document diversity of co-occurring mushrooms (models) and mushroom-seeking flies (signal receivers).
Key recent publications:
- Dentinger, B.T.M. & B.A. Roy. (2010) A mushroom by any other name would smell as sweet: Dracula orchids. McIlvainea 19(1):1-13.
Conferences and workshops:
- Dentinger, B.T.M., R. Manobanda, T. Policha, T.S. Jenkinson, J. McAlpine & B.A. Roy. (2010) Exploitation of mycophilous flies by mushroom-mimicking Dracula orchids. Contributed oral presentation. Special Symposium on Insect-Fungus Interactions, XVI Congress of European Mycologists, Porto Carras, Greece, October 2010.
- Dentinger, B.T.M. (2010) Identifying the models for mushroom mimicry by Dracula orchids. Oral presentation. British Mycological Society Autumn Open Meeting, Royal Botanic Gardens, Kew, United Kingdom, December 2010.
Project partners and collaborators
University of Oregon
National Science Foundation