Jane Schnee identified this unusual plant when Reva Brugnoli, Judy Gersony, Gayle Lafferty, Nancy Soucy, and I visited the North Sebastian Conservation Area yesterday seeking wet flatwoods plants for the on-line Palm Beach Community College class that we are taking. In the xeric scrub, we were enchanted by Adam’s needle, Yucca filamentosa, and the darling curved filaments that inspire its species name.
Like Spanish bayonet (Yucca aloifoia), this plant is a member of the Agavaceae (Agave) family with stiff, sharp-tipped leaves and annual spikes of creamy-colored flowers pollinated only by yucca moths (Tegeticula sp.). These moths lack the long tongues of other butterflies and moths. Instead, they have tentacles around their mouthparts adapted to their intimate, exclusive, and annual relationship with the yucca plants they pollinate. Short-lived, yucca moths do not need to feed. With their mouthparts, female yucca moths gather pollen from multiple plants, which they transfer to the stigma of the yucca plants when they place their eggs in the plant ovary.
As the seeds ripen, they become food for the yucca moth larvae. Surviving seeds reproduce the yucca plant, and the yucca moth larvae falls to the soil to pupate. Male and female adult moths emerge as the same time as the flowers, mate, and the annual moth – yucca cycle of life begins again.