National Geographic : 1971 Apr
I think that Darwin, with true scientific caution, understated the case. Orchids ensure fertilization by contrivances that are often so bizarre as to be hardly believable. Most flowers release pollen in minute particles like yellow dust, but even here orchids are dif ferent, concentrating their pollen in sticky knob like masses called pollinia. One genus of terrestrial orchids attracts the pollenating insect by imitating a female of the same species (pages 493-4). The male attempts to mate with the flower, and so car ries off the pollinia to the next blossom. Another orchid mimics the insect prey of the Campsomeris wasp. The wasp dives on the orchid and stings it, departing with the pollinia neatly glued to its body, to be brushed off on the next flower.* Some orchids shoot the pollinia at the insect; others provide exit tunnels through which the insect must crawl past the pollen masses. Orchidologist Takes a Busman's Honeymoon Dr. Calaway Dodson of the University of Miami, the leading investigator in the field today, described to me the brilliantly colored bees that pollenate highly fragrant orchids of the genera Stanhopea and Catasetum. "The Euglossine bees that pollenate these orchids are iridescent green, gold, and old rose. We calcu late that about 2,000 species of orchids are pollen ated by these bees. "Like most scientists, I am so engrossed in my work that even my honeymoon was a field trip. When I married in Ecuador in 1960, I took my wife to an old cacao plantation where the trees were covered with orchids. I found a budding plant of Stanhopea tricornis and took it back to the hotel to keep overnight until the buds opened. Then we would hang it where the bees could find it. "We kept the plant in the room beside ours, where my assistants were staying. Next morning I got up early and went to wake them. The scent of my wife's perfume was very strong in their room, but she had not been there. Then I saw that the orchid flowers had opened. I returned to our room and sniffed my wife's perfume bottle. The label said Diorissimo, but the scent was that of Stan hopea tricornis. "Well, I dipped bits of blotting paper in the perfume, and, do you know, the bees came to them in preference to the flowers. I kept scattering Diorissimo around, but my wife was very put out when I used up all her perfume to attract 'some stupid bees.' " I told Dr. Dodson that on a jungle river in *For an account of the highly specialized process by which a tiny female wasp pollenates the Smyrna fig, see NATIONAL GEOGRAPHIC for November 1970. 500 3/4 LIFE-SIZE; J. DEQUAIRE Some 450 years ago, Spain's conquista dors found the Aztecs of Mexico adding bits of an orchid'sfragrant seed pod to their cocoa. Vanilla planifolia traveled to Europe and thence to Madagascar. Today the island supplies half the world's needs. The vanillaflower (above) lasts only a day and must be pollenated by hand, since no Madagascarinsect performs the task. To guard against theft, growers prick their initials in the pods (below). When ripe, the pods are spread out to cure under the hot sun ofAntalaha (right). ANDTHOMASA. DEFEO© N.G .S.