Pollinator deception

Flowers of some orchids mimic both the appearance and sex pheromone of virgin females of certain species of bees or wasps. This sexual deception results in pollination by male hymenoptera that would not normally visit flowers. Japanese honey bee drones (Apis cerana japonica) cluster on the oriental orchid (Cymbidiumpumilum) while on their mating flights [ 134]. By comparing volatile profiles of orchids and the female hymenoptera they mimic, or by GC-EAD and GC-MS analysis of orchid volatiles, several compounds have been identified that may mediate this attraction for the solitary bee Andrena nigroaenea [135, 136] and the scoliid wasp Campsoscolia ciliata [135]. 

Ackerman, J.D. (1986). Mechanisms and evolution of food deceptive pollination systems in orchids. Lindleyana 1 108-113. 

Dafni, A. (1984). Mimicry and deception in pollination. Annual Review of Ecology and Systematics 15 259-278. 

Lunau, K. (1992). Evolutionary aspects of perfume collection in male euglossine bees (Hymenoptera) and of nest deception in bee-pollinated flowers. Chemoecology 3 65-73. 

Peakall, R. (1990). Responses of male Zaspilothynnus trilobatus Turner wasps to females and the sexually deceptive orchid it pollinates. Functional Ecology 4 159-167. 

Peakall, R. and Beattie, A. J. (1996). Ecological and genetic consequences of pollination by sexual deception in the orchid Caladenia tentactulata. Evolution 50 ... 

Schiestl, F. P. and Ayasse, M. (2001). Post-pollination emission of a repellent compound in a sexually deceptive orchid a new mechanism for maximizing reproductive success Oecologia 126 531-534. 

Schiestl, F. R, Ayasse, M., Paulus, H. D. et al. (2000). Sex pheromone mimicry in the early spider orchid (Ophrys sphegodes) patterns of hydrocarbons as the key mechanism for pollination by sexual deception. Journal of Comparative Physiology A 186 567-574. 

Evolutionary shifts from reward to deception in pollen flowers. In The Pollination of Flowers by Insects, ed. A. J. Richards, pp. 89-96. London Academic Press. 

Olfactory landscapes and deceptive pollination signal, noise and convergent evolution in floral scent... 

Figure 22.1 Examples from two conceptual axes of interactions between flowers and their animal visitors. Axis 1 is a specialization-generalization spectrum of plant-pollinator interactions. Panel A depicts a guild of red Chilean flowers that share one species of hummingbird as a pollinator. In Panel D, a Perideridia umbel is visited by several families of bees, wasps and flies most are effective pollinators. Axis 2 describes relationships in which animals visit flowers for their own reproductive purposes. In panel B, a female Tegiticula moth gathers pollen from anthers of Yucca filamentosa, for which it is both obligate pollinator and seed predator. In panel C, a Drosophila fly (black arrow) is lured by appearance and smell of decaying matter to a deceptive Aristolochia flower, seen in cross-section. Floral scent plays diverse roles along these axes, including pollinator attraction in food- and sex-based mimicry. All photographs were taken by the author.

Mant J. G., Schiestl F. P., Peakall R. and Weston P. (2002) A phylogenetic study of pollinator conservatism among sexually deceptive orchids. Evolution 56, 888-898. 

Several orchids have remarkably characteristic pollination systems employing sexual deception in this system, the flowers mimic the visual, tactile, and olfactory traits of the females of particular hymenopteran species and so deceive conspecific males into attempting to mate with the flowers. In particular, the floral scent, which has a composition identical to that of female sex pheromones, is a key mediator of this exclusive and species-specific mode of pollination. 

RAGUSO, R.A., Olfactory landscapes and deceptive pollination, in Insect Pheromone Biochemistry and Molecular Biology The Biosynthesis and Detection of Pheromones and Plant Volatiles. (G.L. Blomquist and R.G. Vogt, eds,), Elsevier, Amsterdam, Netherlands. 2003. 

Over the past 25 years, numerous species-specific examples of such deception among plants have been discovered. The deception is so effective that reproductive success in the insect is compromised, with the potentially disastrous consequence to the plant of losing its population of insect pollinators. Fortunately, after being swindled once or twice, individual insects seem to recognize the deception and look for more suitable mates. 

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