Why are wasps seduced by fly orchids?
By Chelsie Vandaveer
July 31, 2002
killerPlants Tendrils: ~~1~~2~~3~~4~~5~~
Suggested Reading: Click here.
Digger wasps (Sphecidae) are solitary creatures. Females dig a burrow in which they lay an egg and place a live but paralyzed dinner. The larval wasp will feed on the caterpillar, spider, or other insect 'mom' left for it. If 'mom' mated, she will lay a diploid egg and a female will hatch. No mating, the egg will be haploid and the wasp a male.
In Europe, two species of digger wasps, Argogorytes fargei Shuckard and A. mystaceus Linnaeus, have a special relationship with the fly orchid (Ophrys insectifera Linnaeus).
The fly orchid is a mimic. The sepals appear as a three petaled flower. The three petals resemble a female Argogorytes. The upper two petals appear as antennae; the labellum appears a wasp body. The fly orchid mimicry is more than simply visual; it produces a blend of aromas that imitate wasp pheromones.
Male Argogorytes cannot resist this resting fragrant female. "Often it [male wasp] remains on the flower for many minutes, every now and then restlessly changing its position before settling down again and performing movements which look like an abnormally vigorous and prolonged attempt at copulation" (The Natural History of Pollination, M. Proctor, P. Yeo, and A. Lack, 1996).
While the male is oblivious to all else, the pollinia (pollen sacs) become firmly attached to his head. Frustrated, the male flies off. He will be seduced by another Ophrys flower waiting to receive the pollen.
Den Virtuella Floran has great photographs of the fly orchid taken by Jens Klackenberg and Gunnar Lundgren. To view the photographs, click on the link:
http://linnaeus.nrm.se/flora/mono/orchida/ophry/ophrins.html
Click on the thumbnails to enlarge the images.
Die Orchideen der Rhön has a wonderful close-up of a male wasp on the fly orchid flower taken by M. Klüber. To view the photograph, click on the link:
http://www.orchid-rhoen.de/Bilder/Ophrys_insectifera/Ophrys_insectifera_01.jpg
killerPlants Tendrils: ~~1~~2~~3~~4~~5~~
Suggested Reading:
What orchid serves alcohol? Renfield's Garden - May 15, 2002
What moth makes insect repellant? Renfield's Garden - August 28, 2002
How does this fly scare predators? Renfield's Garden - April 2, 2003
What bugs are all females in Hawaii? Renfield's Garden - April 17, 2002
What plants were called 'Stones'? Herbal Folklore - April 8, 2002
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