One of my favorite Zale moths is the Horrid Zale moth, worthy of note for its name alone. If you have only ever read about Zale moths, including now, you are probably mispronouncing the name. You might think zale rhymes with tale, but it is actually a two-syllable word that rhymes with ballet, pronounced zah-lay. (Think guacamole, tamale, souffle.)
These moths are not horrible in any way. Horrid comes from the Latin word horridus, meaning “bristly.” And Horrid Zale moths have prominent, bristly scales behind their head and on their mid-section (called a thorax).
Moths and butterflies all have scales on their wings, why their order is Lepidoptera (the Greek word lepido– means “scale,” and pteron means “wing”). Since moths outnumber butterflies by ten to one, ninety percent of the insects in this order are moths. Zale moths are one family of moths in this order. They are noted for their bark-like, scalloped wings that camouflage them on tree trunks and among dead leaves.
Some say the scalloped outer wing edges give them the appearance of a vampire wearing a cape. From a distance, the outer wingtips look as if they have been dipped in white paint, but upon closer inspection, the wingtips look more like they have a bumpy white fungus growing along the edge.
To understand Horrid Zale moths, it helps to understand moths in general. Moths evolved 300 million years ago. Their closest relatives — caddisflies — are aquatic. However, moths evolved to live on land and eat leaves and wood. Most moths today do not have mandibles (or jaws) for eating, but fossils from 190 million years ago show that ancient moths did have jaws. Moths and butterflies evolved the ability to digest plant sugars, such as the ones in plant nectar. At around this time, they also evolved a sucking tube called a proboscis. All the better to help suck up nectar and pollinate land plants. Flowers did not yet exist.
edges of its wings. Credit: Tom Murray
Today, insects pollinate 90 percent of flowering plants, but this was not always the case. The first seed plants, 380 million years ago, had cones instead of flowers. Male cones produced pollen. Female cones produced eggs and a small liquid droplet. The wind blew pollen grains around and they stuck to that droplet, fertilizing the eggs. Insects began sipping the water, and when they did, some pollen grains also stuck to them. These insects carried pollen grains to other plants, accidentally fertilizing them in the process. This method of fertilization worked better than wind pollination. Over time, plants that produced the sweetest water (nectar) attracted the most insects, and therefore survived better than plants that relied on the wind to spread their pollen.
The fact that moths are nocturnal and do not have good color vision posed an evolutionary conundrum to flowers, which had evolved to become colorful to attract the wasps and beetles that existed 120-150 million years ago. To attract night-time moth pollinators, some flowers opened at sunset releasing heavy scents, and they became white to reflect the moonlight.
Being nocturnal, Zale moths have also evolved to become a food source for bats. With bats’ ability to echolocate, Zale moths developed special organs on their mid-section that helped them hear ultrasound bat frequencies that humans cannot hear. Today, some can detect a bat from 100 feet away, diving to escape bat predation or emitting sounds to block bat sonar.
Crickets and frogs use sounds to find mates at night, but Zale moths, active from March through October, find mates by smell. Female moths release pheromones from glands on the abdomen. The female selects a night with a bit of a breeze to carry her pheromones. Male moths can smell the scents up to a couple of miles away, even at very low concentrations.
After mating, females lay about 200 eggs that hatch in two weeks. The nocturnal caterpillars that emerge from the eggs do nothing but eat for about a month before they form a pupa, or cocoon. Late season Zale moth pupae overwinter in leaf litter, and become adults in the spring (If you allow leaves to overwinter in your yard, you help moths survive the winter). After they transform into adult moths, they live just long enough to mate and produce a new generation.
Moths and butterflies have been steadily increasing in diversity since they evolved 300 million years ago. Today there are an estimated 160,000 moth species, most of which have not been identified. Recently, however, their abundance has nosedived, probably due to urbanization and agricultural chemicals, habitat destruction, light pollution, and invasive species. It’s important that we do what we can to help preserve these and other moths with and without funny names like the Horrid Zale moth, including the black witch moth, the hummingbird moth, and the rosy maple moth.
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