"says Macquarie University biologist Anne Gaskett, a battle between wasps and the orchids trying to outsmart them.
Native tongue orchids are pollinated by very confused male orchid dupe wasps. On mistaking the orchid for a female, the wasp lands on the flower and attempts to mate. In the flurry of activity, pollen accidentally picked up by the wasp is ferried from plant to plant. Why wasps get so confused puzzled Ms Gaskett, a PhD student... Ms Gaskett found that the orchids mimic not only the smell of female wasp pheromones, but the colour and shape of the females. "To my eyes the female wasp looks orange and black. The orchids are pink, maroon and orange-red." However, receptors in human and wasp eyes are very different. Unlike humans, wasps see ultraviolet light. When Ms Gaskett used a spectrometer to study the wavelengths of light reflected from orchids and females wasps, she was amazed to find they were virtually identical. "The smell is the most important thing for attracting the insect," she said. "But the colours say this is the source of that alluring fragrance." Ms Gaskett even found the flowers have "curves in all the right places". But in her experiments, male wasps gradually grew wary of mating with orchids. "If I gave them another orchid, a smaller percentage would copulate. They seemed to get wise," she said. ... While the wasps learned through experience to avoid tricky orchids, she suspects the plants have their own evolutionary means of staying ahead. "Only the best-looking and best-smelling orchids will get pollinated," ensuring the next generation is best suited to trick naive wasps. "... As each party ramps up its sophistication, the other party matches it." "The key to the orchids' success is bombarding young, naive male wasps with an extremely compelling sensory overload of irresistible sex signals." Ms Gaskett's next step will be to analyse the seductive orchid bouquets to discover which elements mimic the female wasp pheromones. Her work has been funded for three years by a 2005 American Orchid Society Fellowship." URL : http://www.smh.com.au/news/national/too-overcome-by-allure-to-sniff-the-truth/2007/08/24/1187462523649.html photo : http://www.smh.com.au/ffximage/2007/08/26/annegaskett_wideweb__470x314,0.jpg *************** Regards, VB _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
