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.
But other orchids mimic nectar-bearing flowers, inviting a variety of visitors. These plants need a back-up plan to maintain species integrity. Several Mediterranean species in the genera Orchis (pictured is O. mascula), Anacamptis, and Neotinea keep the gene pool clean by thwarting reproduction after pollination. Crossing experiments reveal that embryos didn't develop, or if they did the hybrid plants were sterile, which is unusual for orchids, report Salvatore Cozzolino of the University of Naples Federico II in Italy, and colleagues in the March American Naturalist. "The type of decep