The yucca moth is very important in the life cycle of the yucca plant. As in other plants, the stigma is the part of the flower which receives the pollen. In the yuccas it is way down at the bottom of a long, hollow tube. A bee can’t get to it. Neither can a hummingbird.
Only a female yucca moth can pollinate a yucca blossom. First she uses specialized mouth parts to collect pollen . Then she drills a hole through the wall of an ovary of a different yucca blossom and lays her eggs inside. Then she goes to the top of the pistil and forces a ball of pollen down the tube. Now the seeds begin to grow, and the moth eggs hatch.
The larvae eat the seeds, but nor all of them. The larvae drill their way out of the seed pod. Then they spin threads and lower themselves to the ground and form cocoons in the soil. In the spring they mature and come out of the ground as little white moths just before the next flowering season. The yucca survives through its remaining seeds. Each of the species, the moth and the yucca, benefit from this process.
*The information here was excerpted from Notes from the Naturalist by Hank Nicol, May 15, 1980 and April 10, 1982.