A Love Story
Yucca glauca plants grow just about anywhere on my property, including in a crack in the sandstone.
This is not your typical love story. For one thing, the descendants of current day subjects have been figuring this out for millions of years. They found each other long before humans arrived on earth.
For another thing, the two species involved are from different kingdoms: plant and animal.
At some point in history, the yucca plant and the yucca moth came to an agreement: You take care of me and I will take care of you. Scientists call it “obligate mutualism” and what it means is that if one of the pair fails, the other cannot survive.
A yucca moth scraping pollen from the anther of a yucca flower’s stamen (male part).
Yucca glauca is a native shrub of the western steppe that grows in abundance on our land. It is not nearly as prevalent as it once was on much of the plains, in part because it is viewed as a nuisance plant by many ranchers.
Once valued by Native Americans for use in everything from basket weaving to food source, the yucca fell out of favor in modern times. The particular species that grows here is also commonly called “soapweed yucca”. The roots can be ground up and mixed with a small amount of water to create a sudsy concoction that can be used as soap or shampoo.
Although it is often overlooked as a food source for wildlife, yucca flowers, pods and even leaves are eaten by pronghorn, deer, elk, cottontails and more.
A cottontail braves the spiny leaves of the yucca plant to get at the tasty flower petals.
Adult yucca moths do not eat. Instead of mouth parts, they sport scrapers at the front of their heads that allow them to gather and hold pollen from the yucca plant.
Yucca moths are rarely seen. Not only are their lives extremely short lived, they spend most of their time inside the blooming flowers of the yucca plant. They travel from one plant to the other at night, getting in place to perform their duties before the sun comes up.
Male yucca moths have one role - breeding. Once the females have mated, they pick a yucca plant, scrape the pollen off the flower anther into a waxy ball and then fly to another plant some distance away to deposit their prize onto the stigma of another yucca flower. The distance ensures diversity is maintained among the plants.
Before the moth drops off the pollen she will check to see if another moth has already laid eggs inside the flower’s ovary. If so, she leaves that plant and finds another. If not, she will lay her eggs deep inside the flower and pollinate it to ensure it will develop seeds which will feed her growing larvae. At that point, her job is done and she will die.
Two yucca moths are almost invisible inside a yucca flower.
As the moth larvae grow inside the yucca plant, they consume parts of the seeds that have developed inside the yucca pod. The moths always make sure they don’t overwhelm a particular plant so there are enough seeds to germinate and make new yucca plants for future generations.
Once the larvae are big enough, they eat a hole in the side of the yucca pod and drop to the ground where they burrow in and overwinter. The following spring, they will emerge as adult moths just in time to start the process all over again.
Yucca seed pods.
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