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Botanists and evolutionary biologists have come up with fascinating answers to many of these questions. John Alcock, an evolutionary biologist and author of An Enthusiasm for Orchids, proposes two explanations for why some orchids would have evolved to avoid a simple nectar reward. When botanists experimented by adding a nectar reward to a normally nectarless orchid, they found that the pollinators hung around longer, happily visiting other blooms on the same and nearby plants. This does not suit the orchid's interests, however, since inbreeding results in lower quality seeds. By comparison, outcrossing, or mixing one's genes with distant mates, increases vigor and variation in one's offspring, maximizing fitness. The sexual frustration of a deluded bee turns out to be an essential part of the orchid's reproductive strategy. Determined not to make the same mistake again, the bee travels some distance and, if things work out for the orchid, ends up pseudocopulating (and leaving his package of pollen) with an orchid a ways off. That distant orchid is likely to look and smell ever so slightly different from the first, and some botanists believe these subtle variations from plant to plant are part of the orchid's strategy to prevent bees from learning not to fall for a flower. "Imperfect floral mimicry" is the botanical term for this adaptation. Think of it: The very imperfection of the orchid's mimicry may itself be part of the perfection of its reproductive strategy.

Another reason so many orchids have gotten out of the restaurant business may have to do with the benefits of developing a relationship with a single, highly devoted pollinator. Nectar, besides being metabolically expensive for the flower to produce, is beloved by so many different animals that it attracts all sorts of riffraff that may not deliver your pollen to the right target. But if you produce a scent that attracts only the males of one particular species of bee, you can insure that your pollen will end up precisely where you want it: on the stigma of a far-flung orchid of your own kind.

The exactitude of the perfume business may also help explain the astounding diversity of the orchid family. A mutation producing even a slight change in an orchid's scent could, strictly by chance, turn out to be the key that unlocks the sexual attentions of a new pollinator, while at the same time completely turning off the original pollinator. In this way, variations in the chemistry of floral scent can function much as geographic isolation does in the creation of new species, by preventing new mutant flowers from being pollinated by older ones. The novel orchid might evolve in genetic isolation from its forebears—a prerequisite for creating a new species.

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