Underwing Moth

The Catocala, also known as the underwing moth, is a genus of moths with bark-like forewings and very bright underwings. They are common in North America, Asia, and Europe and are known for their unique ability to camouflage with their environment and keep predators away by flashing their rear wings.

5 Incredible Underwing Moth Facts

• Seemingly bland in color at first glance, underwing moths have a very colorful rear wing.
• If agitated, the underwing moths flash their rear wings to the predator and begin flapping their wings in a motion so fast that it looks like it’s vibrating.
• Although their rear wings have bright colors that scream “danger” to a predator, they do not actually have any poison to guard themselves against a potential predatory attack.
• There are about 250-260 underwing moths species all over the world.
• Underwing moths have particular sensory organs that allow them to “hear” the sound of bats from a distance.

Scientific Name

Scientifically known as Catocala, the underwing moths are a genus that belongs to the family Erebidae. They were named by Franz von Paula Schrank in 1802. This genus contains at least 250-260 species of underwing moths. The name Catocala comes from two greek words – kato, meaning lower, and kalos meaning beautiful. This name comes from the beautiful rear wings of these moths. This name is pronounced as kah-TAH-kuh-luh.

Underwing Moth Appearance

The underwing moths have very colorful and bright rear wings. Their forewings look like tree bark or leaves, which allows them to hide from their predators. On the other hand, their rear wings are bright in color and patterned in different ways. When camouflaging, they conceal their rear wings to prevent predators from seeing them.

Their hind wings have stripes, which can vary in color to orange, pink, white, red, or black, depending on the species. When threatened, these moths show their rear wings, which throws off the enemy –  a phenomenon known as deflective coloration. When flying, the underwing moths occasionally hide their rear wings in mid-air to deceive possible predators, also called flash coloration. These moths usually have a wingspan of about 2-5 inches, almost as long as a human thumb.

The caterpillars of an underwing moth are grey or brown, allowing them to camouflage into their habitat. In addition, underwing moth larvae can change color to blend with their environment. 

Behavior

The underwing moth is a nocturnal genus, meaning they spend the day resting on trees and the nights wandering. At night, they fly from tree to tree in search of food or, during the breeding season, a place to lay their eggs. This genus of moths is docile, and they tend to stick to themselves. So they do not fly in groups but remain solitary. They remain passive unless threatened or bothered, which is when they begin to move rapidly and show their rear wings. They also start flapping their wings so fast that it appears as though they are vibrating.

Another behavior of the underwing moth is “playing dead.” They can become extraordinarily still if they feel threatened to try and cause predators to lose interest. Underwing moths also use camouflage to protect themselves. They only sit on trees that have the same color as their forewings, making them almost indistinguishable from the bark.

It is thought that any loud noise triggers their sense of smell instead of a startled response. In addition, they have sensory organs that allow them to detect vibrations or sounds at a specific frequency, such as that of a bat, which is one of their main predators.

Habitat

Underwing moths live in forests with the same color bark as their wings, allowing them to camouflage effectively. This means that they typically thrive in deciduous trees. However, they can also be found in caves, under rocks and ledges, and in other bushes or areas that allow them to camouflage.

The caterpillars of underwing moths live in tree canopies or soil. During the day, they hide at the trunk base, and at night they return to the tree to feed on the leaves. 

Almost half of all underwing moth species are found in North America, and the remaining species are found in Asia and Europe. In addition, a few unique species are found in the northern Neotropics and Indomalaya.

Diet

Underwing moths are herbivores meaning that their diet is entirely based on plants. Most of the species feed on deciduous tree leaves in the forest. However, they can also feed on grass and other vegetation in their habitat.

What Eats Underwing Moths?

The underwing moths are preyed on by larger carnivorous animals and insectivores. These include, but are not limited to, birds, bats, lizards, and spiders. The moths often escape these predators by flashing their rear wings and rapidly flapping their wings. The bright color of their rear wings also gives some predators the impression that they are poisonous. However, they are not poisonous creatures.

What Does The Underwing Moth Eat?

The primary food of an underwing moth varies depending on its habitat and the surrounding trees. But overall, this genus feeds on the leaves of the trees within their habitat, usually deciduous trees. They can also feed on grass and other plants within their habitat. Underwing moth caterpillars typically eat poplars and willows.

Underwing Moth Predators and Threats

Since underwing moths are tiny creatures, they are preyed on by many larger animals, such as birds, bats, lizards, and spiders.

Predators aside, other threats that underwing moths face are habitat loss, deforestation, and pesticides. Too much artificial light and a sudden climate change also significantly affect their population.

Reproduction And Lifecycle

The underwing moth goes through a complete lifecycle before becoming fully grown. In the mating season, males locate the females by their pheromones. And once the mating process has occurred, the female lays her eggs soon after. In the summer, the female underwing moths deposit eggs on tree branches, either one at a time or in small clusters. These eggs only take 4-10 days to hatch if laid during the summer, but in winter, it can take up to 3 weeks. Once they hatch, they become a worm-like larva known as a caterpillar. At this stage of the cycle, they do not have wings. Instead, they wriggle around and hide on the branches of trees. After about one month, they become adult moths, and the cycle repeats.

Babies

Baby underwing moths are called caterpillars and have elongated bodies with no wings. These are similar larvae to butterflies, except they are brown and grey instead, while butterfly caterpillars are more colorful. They eat plant material and leaves in their habitat and take about a month to fully mature. At the end of the caterpillar’s cycle, they form a chrysalis, and its body digests itself and forms an entirely new body with wings.

Lifespan

The average lifespan of an underwing moth is not very long, only one to six months, after which they begin to wear out and spend less time flying. Towards the end of their lives, they become susceptible to some common ailments. These include:

• An infestation of fungus on their bodies
• Wing withering diseases – diseases that affect the moth’s wings and impair their flying ability.

Underwing Moth Population

The overall population of the underwing moth genus is unknown. There are around 250-260 underwing moth species living all over the world, most of which have stable populations. However, two of their species in Missouri have a status of Vulnerable. The rest remain Least Concern, considering their rapid reproductive cycle.

Related Animals

• Cabbage Moth
• Peppered Moth
• Madora Moth