Female Tegeticula moths possess maxillary tentacles, appendages found in no other Lepidoptera, which they use to scrape pollen from a yucca anther and hold it as a compacted ball beneath the head. The moth then flies to another flower, inserts her ovipositor into the ovary wall and lays eggs among the developing ovules, and afterwards climbs to the top of the stigma and works the pollen into it.
The act is not incidental to feeding. Adult yucca moths take little or no nourishment, so the pollen is not food; the behaviour ensures the flower sets seed, and the seeds are what the larvae eat. The yucca depends on the moth entirely, and the moth's larvae depend on yucca seed, making this one of the clearest cases of obligate mutualism between a plant and an insect.
The arrangement invites cheating, and it is policed. Yuccas selectively abort flowers that receive many eggs relative to the pollen delivered, which limits over-exploitation. Some related Tegeticula species have lost the pollinating behaviour and lay eggs without pollinating, living as parasites of the mutualism. Larvae eat only a fraction of the seeds in a pod, leaving the rest to disperse.