• Pollen—Menace or Miracle?
    Awake!—2003 | July 22

    • Consider the hammer orchid, which grows in Western Australia. The hammer orchid’s flower has a lower lip that, even to the human eye, almost perfectly resembles the plump, wingless female thynnid wasp. The flower even emits a chemical copy of the sex pheromone, or sex attractant, of the real female wasp! Poised at the end of an arm just above this alluring decoy are sticky bags filled with pollen.

      A male thynnid wasp, lured by the scent of the imitation pheromone, will grab the decoy and try to fly off with “her” in his grasp. As he takes off, however, his momentum flips him and his intended up and over, right into the sticky pollen sacks. After realizing his mistake, he releases the decoy​—which is conveniently attached to a hinge, allowing it to fall back into place—​and flies off, only to be fooled again by another hammer orchid.a This time, however, he pollinates the orchid with the pollen he picked up on his previous encounter.

      But if female thynnid wasps are active, males will invariably choose one of them, not the impostor. Conveniently, the orchid blooms several weeks before female wasps emerge from their underground pupae, giving the flower a temporary advantage.