A Greenhood Orchid
The Love Trap
Published: 21 December 2011 (GMT+10)
Love1 is calling in the temperate forests of Australasia. An exotic perfume (called a pheromone) floats in the air, sending an irresistible message to the males of just one species of insect—the Fungus Gnat—that a female Fungus Gnat is nearby and desires a mate.2 A male gnat answering the call finds that the amorous female appears to be located within the flower of a Greenhood Orchid.3
When a male gnat lands on a protruding part of the flower called the irritable lip or labellum, the lip, which is hinged, suddenly snaps shut, imprisoning the gnat within the flower. Is the gnat about to become the orchid’s breakfast? No, the Greenhood Orchid has a much more sophisticated use for the gnat.
As the gnat explores his tiny prison, he notices light coming in from a ‘window’ above him. Could it be an exit?
As the gnat crawls up to investigate, he has to squeeze along a narrow tunnel lined with hairs. In doing so, he brushes against two strategically placed parts of the flower. The first exudes a sticky liquid, and from it he receives a dab of glue on his body; the second provides a parcel of pollen which adheres to the glue as he moves forward. Ahead is an exit, and the gnat makes it out into the world again, but now carrying the Greenhood Orchid’s means of reproduction.
The orchid takes from 30 minutes to an hour to reset the lip, thereby providing the means whereby another gnat will enter the flower.
Love frustrated, the male gnat flies off in search of romance and is soon lured again by the fragrance of another Greenhood Orchid. It seems he has not learned his lesson and the call of love is too strong. This time he will fertilize the other orchid with the pollen he is carrying on his back. The orchids also have their stigma (the ‘female’ part in plants that receives the pollen) strategically placed in the path of the gnat, ready for a ‘loaded’ one.
A Fungus Gnat
Creation and selection
Orchids have much variety in their reproductive mechanisms. Although it might be tempting to see this as an example of specific design, it may be that the potential for a number of different adaptations was present in the original orchid ‘kind’. Selection (artificial, through breeding) has been able to ‘cull out’ the various types of dog from an original mongrel dog/wolf population, all without any real new information arising. So this process does not show any ‘evolution’ of the sort that could have turned one-celled microbes into wombats, wisterias and Web designers, because this would require lots of new genetic information—for making hair, noses, ears, brains, etc. A similar selection process may have conceivably ‘fine-tuned’ this orchid’s pollination process.
There are many ‘species’ of orchids that have variations on the theme of the hooded orchid. By using different combinations and concentrations of a suite of some 100 or more aromatic chemicals, the different orchids attract different species of flies, wasps, gnats, bees, etc. The shape of each type of orchid is fine-tuned to the particular insect that it attracts to do the pollination.
Did God create the thousands of different variations, or did He create the basic orchid kind with the capacity for producing the varieties we see today? The fact that so many orchid species and genera can be readily hybridized suggests that a lot of the variety we see has occurred through adaptation. Natural selection, discovered 25 years pre-Darwin by the creationist Edward Blyth, is involved in selecting the variations—variations that occur through recombining the created genetic information—that best fit the orchid flower to its pollinator.
Some features might even arise through loss of genetic information via mutations—for example, the clear panel in the hood could have arisen through inactivation of genes in the hood that make the different pigments (green, red, yellow, etc.). But there is no way that these processes could change an orchid into a mango tree, for example, because this would need lots of new genetic information, and that needs an intelligent creator to invent it.
Orchids testify to the creative genius of God. They were created without the nectar that other flowers have to attract pollinators, but with the capacity for producing the aromatic sex attractants, and the ability to adapt to the insects available for pollination. We now marvel at the intricate interactions between the hooded orchid and the hoodwinked gnat.
References and notes
- The word ‘love’ is used in this article for effect. It is not suggested that insects have feelings akin to those of human beings. Return to text.
- Fungus Gnats, also called Mosquito Flies, are small (about 3–4 mm or 1/8 inch long) mosquito-like flies that feed on fungi, not the pollen of the plants they enter. Return to text.
- Any orchids of the genus Pterostylis. The flowers are mostly green and resemble a hood; hence the common name, greenhoods. Most species are found in Australia, with others in New Zealand, New Caledonia and New Guinea. So far more than 120 species of greenhood have been named. Return to text.
- The fact that the process involves ‘deception’ is not a problem, as animals and plants are not moral beings. Return to text.
- For a further example of ingeniously designed orchid pollination, see Chapman, G., Orchids … a witness to the Creator, Creation19(1):44–46, 1996. Return to text.