Other Environmental Themes

The Wily Way of Plants

Pollination involves a cooperative effort between plants and animals. Sometimes this partnership is based on trust and sometimes on outright duplicity. For example, insect orchids of the Ophrys genus produce a flower petal that physically resembles a female wasp to lure unsuspecting males. In addition, the plants give off a scent similar to that emitted by lusty female wasps. While attempting to mate with the female decoy—a behavior called "pseudocopulation"- -the male wasp picks up pollen that may later pollinate other orchid flowers that catch his eye.

Many of Charles Darwin's ideas about evolution were drawn from his observations of orchid pollination. Darwin was particularly intrigued by the techniques employed by orchids to attract and deceive potential pollinators, describing these machinations in a two-volume treatise, "The Various Contrivances by Which Orchids are Fertilized by Insects."

Pollination is not built entirely on chicanery and can be a more straightforward give-and-take. For instance, plants generally compensate pollinators by offering, and delivering, sweet treats in the form of nectar. Cubretum laceolatum, a flowering shrub found in western Brazil, goes one step further, producing a gelatinous candy with the consistency of gumdrops—an item that appears to be popular with dozens of the area's bird species.

Animal pollinators rely on a variety of cues to find a satisfying meal, guided by a flower's color, size, shape, and structure and, to a lesser extent, by the fragrances emitted by flowers. Bright patterns of contrasting colors, such as those displayed by the sage plant, can lead insects to nectar and pollen in a flower's center. After being pollinated by butterflies, yellow lantana flowers turn red—a color butterflies cannot perceive—so that the insects will be directed toward other unpollinated flowers. Other flowers like scarlet gilia change colors over the course of a season to attract a different class of pollinators.

The diverse tactics used by plants to get themselves fertilized are impressive and, at times, hard to believe, until one realizes that nature has had roughly 100 million years to perfect them.