Yucca (Yucca glauca), the state flower of New Mexico, illustrates an intimate relationship between a specialized pollinator and its equally specialized flower. The plant and the insect co-evolved; that is, they developed in intimate connection with each other. This is called an obligate mutualism in which if one were to disappear, the other would follow the same path. Originally it was a relationship of exploitation, with the moth larvae feeding on the seeds of the yucca. But, eventually the plant devised methods to take advantage of the situation and as a consequence, the moth also evolved to ensure food for its babies and preservation of its food plant.
The yucca adds a special embellishment to this arrangement; of all the insects that visit its flowers, the only ones that can accomplish pollination are the yucca moths (Tegeticula yuccasella and Parategeticula depending on the species of plant).
Then, just as purposely as before, she goes to the right place, at the top of the ovary (called stigma), and deposits some of her precious cargo of pollen from under her chin, ensuring, this way, that the seeds will grow and feed her babies. She repeats this operation in other flowers.
The larvae feed on some of the seeds and there are enough left for the plant to reproduce. When fully grown, the larvae drop to the ground, where it goes through the transformation called pupation and finally it emerges as an adult several months later to repeat the cycle.
Without this insignificant little moth, the landscapes of the west would look dramatically different in the absence of yucca.
|© Cillas. Wikicommons|
Moths as Pollinators
List of articles
Beginners Guide to Pollinators and Other Flower Visitors
© Beatriz Moisset. 2012