These deceptive orchids belong to the genus Ophrys, a large group of orchids belonging to the subtribe Orchidinae. They are widespread in areas of Australia, New Zealand, Europe, North Africa, the Canary Islands, and the Middle East. These orchids are unusual because of their success in reproducing using pseudocopulation, mimicking the female of a particular insect species so well that the male is fooled into attempting to copulate with the flower.
Amazingly, the orchids in the genus Ophrys are able to attract male pollinators of a specific species of insect by producing a sex pheromone of virgin female pollinators. The role that scent plays is the most important aspect in getting the male pollinator to engage in pseudocopulation with the labellum or “lip” of the flower. The flower is then ensured of depositing pollen on the head or abdomen of the male pollinator.
Every Ophrys has its very own pollinator insect and is dependent on that insect species for its survival. And if you think all the male insects are stupid enough to keep coming back to the same flower, thinking they are reproducing with a like-minded female, researchers have discovered it doesn’t take but a time or two for a male to figure out what is going on. Only about 10 percent of an Ophrys population gets successfully pollinated.
The spider orchid: Deceptive beauty of Australia
Ryan Phillips of the Australian National University in Canberra thinks the spider orchids are the most beautiful of the deceptive orchid species. Their flowers don’t look like insects, so they rely on scent and chemistry alone to achieve pollination. The scent of the spider orchid mimics the pheromones of a female wasp, and the males go crazy zig-zagging between the flowers following the scent.
Many of the males “either get tricked more thoroughly or are more desperate.” says Phillips. These guys make repeated visits to what smells like a luscious female. Through trial-and-error, other males “tend to learn to avoid that specific flower.” You would think all the males would catch on, but pollination actually takes place with more of the newly emerged males than the older ones.
Australia’s hammer orchids are unusually tricky
If you look closely at the labellum of the hammer orchid, you notice it looks like an insect. It is attached to a narrow stem that holds it aloft, like a hammerhead on a hinge. What is deceptive and very clever about this fake hammerhead is its purpose. This orchid is only pollinated by the male Thynnid wasp. The labellum of the orchid resembles a wingless female Thynnid wasp. Because female wasps are flightless, they wait on top of stems to be carried off by the male wasps. Copulation occurs in mid-air.
When the male wasp is attracted to the pheromones produced by the orchid, he will try to grasp the fake female in order to fly away with her. But the male’s movement on the labellum causes the hinge to activate, throwing the male backwards and putting its thorax in touch with the flower’s sticky pollen pack. The male eventually gets tired of trying and flys off, hopefully, to find another spider orchid. The spider orchid is dependent on a male wasp going to another plant first and then coming to it so the orchid will be pollinated. This is not a mutual admiration, as the wasp gets nothing in return.
The Dark-banded greenhood is even more deceptive than the hammer orchid
The dark-banded greenhood is even more clever than the hammer orchid in ensuring it gets the maximum amount of pollen from its male pollinator. Fungus ants from the genus Mycomya are the hapless victims of this deceptive plant. This orchid also has a hinged lip that swings backward when touched by the male insect. This forms a tube with the flower column and wings of the flower. The insect is thrown down the tube, and tiny bristles along the tube aid the insect in slowly crawling out to freedom, leaving behind its stash of pollen while picking up new pollen from the plant.
Using food-deception instead of sex is another method to ensure pollination
A very common deception used by plants is food-deception, where orchids take advantage of the pollinators tendency to associate perceptual triggers with certain food sources, like nectar. The green-veined or green-winged orchid found mainly in Europe produces a scent like nectar, its main pollinator, the queen honeybee absolutely loves. But being a deceptive orchid, the honeybee gets nothing for its efforts and the plant gets the pollen it needs to reproduce.
The green-winged orchid doesn’t really need a queen honeybee to reproduce because it is a hermaphrodite, having both male and female sexual organs. This can, of course, place limitations on genetic diversity, but it is always there as a backup when honeybees aren’t around. The world is full of many amazing and wonderful plants and animals, and orchids are just one part of our diverse ecosystem.
