By Frances Lamberts
The yucca plant, common in our area, displays numerous large, creamy-white, nodding flowers on tall stems during May. It exemplifies how plants and their pollinators have co-developed over their long, millions-years evolutionary history, some evolving very special knowledge and behavioral traits to assure long-term survival chances for their off-spring.
An article in a U.S. Forest Service newsletter describes the extraordinary partnership between this plant and its small, white pollinator, the yucca moth. It notes that, without the skills and seed-sparing behavior by the moth, neither organism could live.
The male and female moth emerge from underground cocoons in the spring, in synchrony with the yucca plant’s flowering. They meet and mate in the blossoms, after which the male dies and the female’s job begins. She gathers pollen from several flowers’ anthers, holding it in a ball under her chin. She deposits from it on a flower’s stigma to begin the fertilization process and lays eggs in its ovary to secure food — the subsequently developing seeds — for her larvae.
On any flower, she checks its visitation history, going to another plant if the scent reveals other moths to have visited before her. If not, she lays a few — no more than a handful — of eggs in the ovary.
“This is good for the plant and for the future babies,” the article notes. “With too many eggs in the ovary, the flower would abort and the larvae would starve.”
During her short, few days of adult life, spent to assure reproduction of the yucca plant and nursery food for her own progeny, she does not feed at all.
Also during early May, pipevine swallowtail butterflies were fluttering the trellised vine of the Dutchman’s pipe, laying egg masses on the undersides of its large leaves, resulting in several dozen larvae. For protection, these feed close together while very small, separating only when two rows of orange spikes on the body will alert potential predators of a poisonous quality the vine confers to its butterfly.
This plant, too, evolved a special relationship with its pollinators, small gnats or flies which it traps in the flower until fertilization is assured. Yet an article in the Nature journal reports that, since the Dutchman’s pipe ‘wants’ to keep these visitors alive, it secretes a little nectar to get them by until release.
Nature displays many ways of cooperative and wise, sparing use of her resources to allow future generations to thrive. We have much to learn from her.