Southern Flannel Moth

The Southern flannel moth (Megalopyge opercularis) is a species of moth native to the Southern United States. The adult moth has a wingspan of about 1-1.5 inches and is variably colored gray to brown with creamy yellow accents and a rusty-orange thorax. The Southern flannel moth looks like it could use a haircut. These little moths are covered in setae (singularly, seta) that resemble hair or fur. Keep reading to learn more about these interesting creatures!

Five Fabulous Facts about Southern Flannel Moths

• The Southern flannel moth is native to the Southern United States, primarily in the Gulf Coast region.
• Southern flannel moths are covered in fine setae that resemble fur or flannel.
• The adult moth has a wingspan of about 1 inch and is primarily gray or brown in color.
• The larvae, also known as puss caterpillars, have long, dense, stinging hairs that can cause severe skin irritation and even anaphylactic shock in some individuals.
• The stinging sensation caused by the caterpillars’ venomous hairs can last for several days, and in some cases, the venom can cause an allergic reaction

Southern Flannel Moth: Scientific Name

The Southern flannel moth’s scientific name is Megalopyge opercularis. Megalopyge loosely translates to very large bottom. This name is almost certainly a nod to this moth’s pearlike shape. Opercularis is Latin for cover and is thought to refer to the lid of the species’ cocoon. However, it might be a reference to these small moths’ furry little bodies. They have large areas of brown-to-gray on their forewings with white hairs covering them. The thorax is covered with rusty-orange hairs. Their legs are covered in yellow hair, and their feet in black hair. In other words, they have very hairy covers!

Appearance

The Southern flannel moth has three distinct sections: head, thorax, and abdomen. All three sections sport long setae, or bristly hairs. These setae give the moth the appearance of being quite furry and soft, like an old flannel shirt. The head is covered in setae, with two long antennae protruding from its top. The antennae of females are thin and white, while males have feathery yellow antennae. Their abdomens are fluffy and are colored from caramel to brown to gray. The thorax is covered in orange setae. The wings are small and fringed with setae and are typically held against the body when at rest. The legs are also covered in long, yellow hair with black feet. Adult moths are relatively small, measuring about 1 inch in length.

Behavior

Southern flannel moths are known for their fuzzy, flannel-like appearance and their tendency to fly during the day. They are not considered aggressive and do not pose a threat to humans. These little moths are much more interesting in their larval form. In their larval state, these moths are called puss caterpillars. Puss caterpillars are known for their vicious sting, the pain of which has been compared to a heart attack or limb amputation. Adding insult to injury, the caterpillars also cause damage to agricultural crops by eating the leaves of plants like cotton and peanuts. However, Adult moths do not sting and are unable to cause crop damage as they can’t eat! Southern flannel moths have vestigial mouthparts, meaning that their mouths are too small and underdeveloped to be functional. Most flannel moths produce two broods, though those in the deep South will produce three.

Habitat

Southern flannel moths are found in the Southeastern United States, primarily along the Gulf Coast, and in Mexico. They are commonly found in wooded areas, such as deciduous forests, but can also be found in urban and suburban environments. The adult moths are typically active during the late summer and fall, while the larvae, or caterpillars, are present from spring to early fall. Adult moths are visible near the plants on which they will lay their eggs. Their larvae, puss caterpillars, feed on a wide variety of plants. Trees such as oaks, elms, and pecans, are preferred. However, they are also found on agricultural crops such as cotton, peanuts, and corn. Their larvae cause damage by feeding on the leaves and fruit of these plants, reducing crop yields.

Southern Flannel Moth: Diet

As mentioned previously, Southern flannel moths do not eat. Instead, these moths rely on energy stores from their larval stage in which they grew plump on the leaves of various plants including trees, shrubs, and agricultural crops. these moths have vestigial mouths.

Predators

There is not much information readily available on this species’ predators. There are anecdotal reports of a lacewing feeding on the eggs of the Southern flannel caterpillar, and a lizard eating a later instar, before rubbing its mouth against the ground, suffering, no doubt, from the punch of the sting. Lacking direct evidence, it is assumed that like many species of moths, their natural predators include birds, bats, and insects such as praying mantises, lady beetles, and ants. It is also possible that other mammals and reptiles may also prey on Southern flannel moths.

Threats

Southern flannel moths face a number of threats including habitat loss, pesticide/herbicide use, and climate change. As their preferred habitat is longleaf pine forests, the destruction of these forests is leading to a decline in the Southern flannel moth population. Pesticides and herbicides used in agriculture and residential areas are also harming the moths and their larvae. Climate change is having an impact, as changes in temperature and rainfall patterns disrupt the timing of the moths’ lifecycle.

Southern Flannel Moth: Conservation Status

The Southern flannel moth is not considered an endangered species. However, this species is not well-studied and many factors affect insect populations which fluctuate from year-to-year. For more information regarding the status of these moths in your area, contacting a local expert or organization, such as a university entomology department or a conservation group is recommended.

Lifecycle

The Southern flannel moth goes through four stages in its lifecycle: egg, larva, pupa, and adult.
The female moth lays her eggs on the underside of leaves of host plants, such as holly, oak, and pyracantha. The eggs are small and round and are usually laid in clusters. After hatching, the larvae (caterpillars) feed on the leaves of the host plant. They are fuzzy and have distinctive yellow-orange colored tufts of hair. They also have a venomous and painful sting. Once the larvae have grown large enough, they spin a cocoon and pupate. The pupa is reddish-brown and is usually attached to a leaf or twig. After about two weeks, the pupa emerges as a moth. The moths are small, with a wingspan of about 1-1.5 inches.
The lifecycle from egg to adult takes between 5-6 weeks.

Population

Southern flannel moths are not considered a major pest species, and as such, their population numbers are not regularly tracked or monitored by the government or academic organizations. Additionally, the population of any given species can fluctuate greatly depending on a variety of factors such as weather conditions and predation

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