"Presented with the right specimen, a male orchid dupe wasp ejaculates... on the petals.
Anne Gaskett, a biologist at Macquarie University in Sydney, Australia, ... led a study of the insect's amorous intentions toward two species of Australian tongue orchids. "It's just so hard [for the wasps] to resist," she says. ... Many species produce female-mimicking perfumes that lure males into spreading pollen. But most insects merely touch down on the flowers. Gaskett noticed, however, that dupe wasps (Lissopimpla excelsa) spent a lot of time around tongue orchids. Many left a visible blob on the flower after flying away. "We decided to check if they were wasting their sperm on the flowers," she told... The biologists confirmed under the microscope that the blobs were composed of sperm cells. Next, Gaskett set up field experiments to determine how often the wasps "had sex" with the flowers and whether they eventually learned from their follies. ... On first visiting a tongue orchid, nearly three-quarters of wasps left sperm on the flowers. But after repeated visits, most insects stopped copulating with the flower. ... "They are perhaps not really educated about what a real female looks like, and they make a bad decision," Gaskett says [males, indeed !]. ... "The orchids that caused the most extreme behaviour pollination with ejaculation have the highest pollination rate of any known sexually deceptive orchid," she says. ... Gaskett thinks that the peculiar reproductive lives of the wasps might explain why males have not evolved to discriminate against orchids. Female wasps reproduce asexually that is, without male help to spawn males, while sexual reproduction between both sexes produces only females. "If you are the female and you miss out on mating because your male is out with an orchid, you can still reproduce," she says. The real winners are the orchids. By duping male wasps into ignoring females who in turn breed more males, tongue orchids ensure their legacy, Gaskett suggests. "It's a very interesting hypothesis," says Florian Schiestl, an orchid expert at the University of Zurich, Switzerland. A simple test would be to see if populations of orchid stud wasps have more males than a related species that is not attracted to flowers, he says." URL : http://www.newscientist.com/article/dn13642-orchids-sexual-deception-triggers-ejaculation.html?DCMP=ILC-hmts&nsref=news1_head see a video ["The tongue orchid so successfully fools the orchid dupe wasp into thinking it is a female wasp, the insect actually ejaculates"]: http://uk.youtube.com/watch?v=PEXHiBSTg8M ************** Regards, VB _______________________________________________ the OrchidGuide Digest (OGD) orchids@orchidguide.com http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
