Carlos Martel(1)*, Wittko Francke(2) and Manfred Ayasse(1)
(1) Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Helmholtzstraße 10-1 Containerstadt, D-89081Ulm, Germany
(2) Universität Hamburg Institut für Organische Chemie, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany
Telipogon is a Neotropical orchid genus that grows exclusively at mid elevations in the moist and cloud forests of Central and South America. The pollination system in Telipogon is through sexual deception in which the flowers mimic the females of their tachinid fly pollinators. Telipogon peruvianus has evolved a particular pollination system in which male tachinid flies of Eudejeania aff. browni developed precopulatory behavior only. However, the basis of how tachinid male pollinators are attracted to the flowers are largely unknown. Therefore, our aim was to identify the basis of the pollinator attraction in Telipogon peruvianus. To do so, we carried out floral scent collection, chemical analysis, electrophysiological analysis, colorimetric analysis and behavioral experiments in wild populations of Peru. We show that male pollinators are able to smell some compounds of the odor floral bouquet of T. peruvianus flowers and that synthetic mixtures of those electrophysiologically active compounds are attractive as much as the flowers of T. peruvianus itself. Some of those electrophysiologically active compounds were also found in the cuticular hydrocarbon extracts of the pollinators’ attractive females. Furthermore, Telipogon peruvianus flowers also reflect UV wavelengths as it was observed in the flowers of Dendrophorbium longilinguae, on which the tachinid pollinators feed. We propose that T. peruvianus flowers imperfectly mimic two models, the female tachinid fly and the flower where tachinid pollinators feed. Our conclusion is that although both olfactory and visual stimuli are important for pollination attraction, olfactory stimuli are key in the cheating of Eudejeania aff. browni males and guarantee the pollination success of the sexually deceptive Telipogon orchids.