MYSTERIOUS MOTHS

 

A Titan Sphinx Moth is a strong flier that can be found from the tip of the Keweenaw Peninsula down to Argentina. It has a long proboscis (tongue).

 

Story and photos by Scot Stewart

When the moon arrives in the darkness,
The moth appears at the disappearance of sunlight.
It flickers its pale wings as it shakes from its deep slumber,
To go search for food
To carry it through the night.
– Suzy Kassem, from “The Moth and the Butterfly”

Sometimes silent, sometimes zooming past in a wash of buzzing, moths are true mysteries of the night. Because they are mostly creatures of darkness, they are not well-known to most—certainly not nearly as well know as their close relatives, butterflies. Ironically, there are about nine times as many moths on the planet as there are butterflies. Currently, there are approximately 11,000 species of moths identified in the U.S. and more than 135,000 identified around the world. However, there are more, probably many more, that have not been identified
Moths are unlike butterflies in a number of ways that often make them less noticeable and harder to find. They have a larger range of size than butterflies, running from the cecropia’s 5- to 7-inch wingspan to “micro-moths” with wingspans measuring a little more than 0.2 inches; incredibly, 1/5 of an inch is still twice the size of the world’s smallest recorded moth.
Even the biggest moths may be difficult to find. Cecropias live only two weeks or so as adults. Their sole job is to find a mate—males use feathery antennae to detect pheromones produced by females up to seven miles away—and for females to lay around 100 eggs after mating.
Adults have no working mouth parts and do not eat during this stage in their lives. They emerge from cocoons looking very plump and rely on stored energy to survive during this reproductive period. Luna moths, beautiful apple-green moths with long tail extensions on their hind wings, only live a week and have no mouth parts at any stage of life.

 

The eye-catching Luna Moth has a bright green color and a typical wingspan of about 4.5 inches. Once it emerges from its cocoon, the moth never eats and lives only about one week.

 

Micro-moths, like leafminers, are difficult to find simply because they are so small. The small birch leafminer moth is only half a centimeter long. As a larvae—or caterpillar—the leafminer lives between the layers of cells in birch leaves, tunneling through the tissue and eating the middle layers, creating an ever-widening path. The tunnels are not visible unless one really looks for them. Because the adults are so small, these moths are rarely seen.
Most moths are nocturnal, meaning adults are most active at night. Famous for their attraction to lights, they do congregate around porch and streetlights and will flock to lights aimed at white sheets outdoors. Add an ultraviolet light to the mix, and all kinds of insects will be attracted. This scientific method is key to finding, surveying and identifying moths in an area.
Animals that hunt moths must have great night vision, sonar and often great hearing, too. Bats use sonar, emitting high-pitched sounds and using their large ears to collect the reflected sound waves that let them zero in on their prey in a process called echolocation. Tiger moths, however, can produce clicking sounds to jam bats’ sonar. Owls, like northern saw-whet, use great hearing and night vision to catch moths. Common nighthawks and whip-poor-wills may hunt all night, relying primarily on night vision and on bright, moonlit nights. They have hair-like feathers at the edges of their large mouths to help find and guide insects to their open mouths while flying.
Most other moth hunters must rely on their great vision and good luck to find moths at their daytime roosting sites. These include in the crevices of tree bark, near the roots of grasses and the undersides of branches and other large objects.

There was a moth in there, and it still had its wings
crumpled up, and it was just starting to pump its wings up. Life continues in lots of places, and life is a magical thing.
— Laurel Clark

Like butterflies, moths are insects passing through life in four stages: egg, larvae (caterpillar), pupae (cocoon) and adult. Eggs and larvae for both butterflies and moths are relatively similar. As caterpillars, moths become eating machines, not much more than bags of muscles and digestion. Many have hair-like structures they use to help them feel their way along, as they have poor vision due to small, simple-lens eyes. As adults, they will have compound eyes with vision capable of seeing ultraviolet light.
With only cryptic coloration or occasional spines, larvae have little protection from predators. Some can drop from host plants and disappear into the vegetation below. Some, like forest tent caterpillars (also known as army worms), gypsy moths and fall webworms can appear in large groups, providing a safety-in-numbers approach of confusing some predators. The hairs on fall webworms and their bivouac silk structures also make predation more challenging. Still, they provide a huge supply of food for many birds, reptiles and other animals in their respective ecosystems.
Moth larvae provide significant economic concerns and opportunities for humans as well. Fall webworms, army worms, gypsy moths and spruce budworms can inflict major damage on forest trees; some damage from these insects can be observed from space! Spruce budworms kill large stands of conifers, including spruce in the Upper Peninsula.
Tomato hornworms, also known as five-spotted sphinx moths, are large moths with large larvae able to not only eat tomato leaves but small green tomatoes, too. They can create havoc in gardens, especially in the southern parts of the U.P. and Wisconsin.
Pantry moths, Indian meal moths and Mediterranean flour moths feed on cereals, nuts and even bird seed in homes. Their life cycles can range from as little as 30 days to as many as 300, letting them quickly reproduce in a food supply like a pantry full of cereal boxes. A combination of moth traps and active examination and elimination of potentially contaminated foods is necessary to rid a home of them.
Clothes moths, also known as wool moths, can also be a concerning household insect. The larvae of these moths feed on plant and animal fibers like wool and cashmere in suits, pants, coats and other clothing, leaving small holes in the fabric. Placing clothing outside in sunlight, bushing clothing to remove eggs and cocoons or freezing clothing in polyethylene for three days are all ways to remove some clothing moths, but dry cleaning is the only way that is 100 percent effective.
Perhaps the most economically important moth—and one that’s also connected with fabric—is the silkworm. During the Han Dynasty (220 BC – 207 AD), people discovered ways to unravel the silken fibers of this Chinese moth’s cocoon and turn them into a fine thread. The cocoons are processed after the moths emerge and lay their eggs to make it easy to continue raising the insects. The thread made from the cocoons was and still is used to make the most desired cloth in the world, silk.
Soft, durable and warm, silk became the base of Chinese trade with the Roman Empire and other regions in what is today western Europe to north Africa. It spurred the development of a network of roads to aid travelers carrying silk, paper, spices and other Chinese products west in exchange for furs, gems, vegetables and other desirable goods. Even more importantly, culture, religious ideas, science and philosophy were also exchanged. The Chinese worked hard to protect silk production secrets, punishing those who tried to export the insects. Portions of the Great Wall of China were extended to protect traders traveling across the northern sections of China as they traveled west. These moths truly helped change the ancient world.
Moths make two basic types of cocoons. The more common is the traditional silken case, which protects the pupating moth. The second, often found on the surface of soil under leaves and other debris, looks more like a butterfly’s chrysalis and is lightly framed with strands of silk or completely bereft of it.
Becoming more acquainted with moths is an easy and surprisingly exciting venture into a new view of the natural world. Simply leaving a porch light on and watching the walls outside for a short time on a warm evening is a great way to start. Moths will appear at those lights into October. The larger moths in the area—luna, cecropia and polyphemus—all make their appearances early in June, depending on the weather. This year, with the cool start of spring in May, many of nature’s events were delayed a few weeks.
Visiting commercial and institutional buildings where outside lights are on all night may lead to moths that came late to the lights or simply stayed as the night cooled down and were left with insufficient energy to fly to safer quarters. These moths may be roosting very near those lights. Underwing moths often stay into the following day. With mottled gray wings, they blend in well with tree bark, where they often spend daylight hours. But if they open their wings and reveal their lower wings, they will startle most with rings of white and black, orange and black or even crimson and black. These colors are meant to surprise potential predators.
Other surprising moths are the clearwing or hummingbird moths. These moths are active during daylight hours. Their wings have few or no scales on them, and the color of their bodies is either forest green or brown. They feed on nectar using long, coiled tongues that are unrolled to probe into tube flowers. Their appearance and behavior mimic hummingbirds, and many people mistake them for baby birds.
Sphinx moths are another group of diurnal (day active) moths. They also feed on nectar and can be found into September and even later in locations south of the U.P. Some, like the five-lined sphinx, are quite colorful, sporting bright pink bands on their abdomens. Often fearless, they can be extremely entertaining to watch; they are capable of hovering for a half hour or more as they feed on the nectar of tube-shaped flowers, milkweed, thistles and other large flowers. A large patch of a flowering Bouncing Betty attracted a number of sphinx moths to a stretch of trail at the Presque Isle Bog Walk several years ago, providing a treat to hikers.
Many night-blooming plants rely exclusively on moths for pollination. Both clearwings and sphinxes are important pollinators of day blooming plants too. Because their bodies are covered with long scales that act as dust mops, they help these plants by sweeping up and carrying pollen on to the next flower. These scales are a noticeable difference between moths and butterflies; moths’ scale-like structures covering their adult bodies are generally furrier in texture and appearance.
Moths do play other important roles in our world. In some parts of Africa, 90 percent of the people eat butterfly and moth larvae, making insects an important source of protein for them. But for most of us, seeing a moth is an opportunity to observe something adapted to a condition that’s not too familiar to us: the dark. As we come to better understand moths, their mysterious lives become easier to grasp, more enjoyable to experience, and more exciting to be a part. We can all learn a thing or two from watching the moths that seem to dance around our porch lights at night.

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