Yucca Moth

While many may think of moths as the butterfly’s ugly cousin, a small boring insect flying around their porch lights at night, they are anything but. Ohio has over 3,000 species of moth. Most of them are nocturnal, many are colorful, some are large, and all are important members of their ecosystem. One of these moths is the yucca moth, a hardworking nighttime pollinator. Many plants are pollinated by only one species of moth. The yucca plant is one such plant. Through 40 million years of evolution, the plant and moth have forged a symbiotic relationship depending on each other for their very existence.

This small white moth’s entire life happens in, on or under a yucca plant. During late June yucca plants flower at night. Their creamy white flowers seem to float above the ground in the moonlight. New moths emerge just as the yucca plant is blooming. Their only purpose is to mate. Unlike most moths the yucca moth doesn’t have a long tongue – yucca flowers don’t produce nectar. Instead, the females have evolved tentacles around their mouths for scraping pollen off the anthers of a yucca flower. After gathering pollen and storing it in a ball under her chin she flies to another flower on a different plant. After making sure another moth hasn’t laid eggs in the flower – her antennae can pick up the scent of another female – she lays a few of her eggs in this new flower. This information is important to both the plant and the moth – if too many eggs are laid in a flower the plant drops the flower off. This is a mechanism developed by the plant to ensure their arrangement with the moth isn’t abused. Now she moves to the stigma which has been specifically shaped to accept some of her pollen ball. The flower is now fertilized, and a fruit will grow. She repeats this activity on more flowers. Several weeks later caterpillars are eating some of the developing fruit seeds, but not all, leaving plenty to make new plants. Eventually the caterpillars chew their way out of the fruit and burrow, up to a foot deep, underground where they make a cocoon and wait for the yucca plant to bloom. This carefully orchestrated cooperation allows both plant and moth to produce a new generation.

All nocturnal moths are facing many challenges including pesticides/insecticides, loss of habitat, climate change and artificial light at night. Yucca moths are drawn to light sources at night.

Moths drawn to light are not mating and they are not pollinating plants. Under the light they will die due to increased predation or exhaustion before daylight. Let’s help these unique moths thrive by protecting dark skies so that they can continue to play their role in the ecosystem.

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