Promiscuous orchids

Some orchids use sexual deception to entice a pollinator, mimicking the scent of a specific female wasp, for example. This plant-pollinator monogamy maintains genetic isolation and prevents undesirable pollen from clogging up the works.

Corbis

But other orchids mimic nectar-bearing flowers, inviting a variety of visitors. These plants need a back-up plan to maintain species integrity.