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Moth of the Week

Southern Flannel Moth

Megalopyge opercularis

The southern flannel moth is a part of the family Megalopygidae, the family of flannel moths or crinkled flannel moths. It was described by Sir James Edward Smith in 1797. They get the name “flannel moth” from being covered in setae, hair like bristles that give them a fuzzy, soft look.

Description Adult moths have round, hairy bodies ranging in coloration from cream at the bottom to yellow or light brown at the head. It’s legs are the same brown as the body with black feet. The forewings fade from a darker brown to cream with black/dark brown at the top edge or “costal margin.” The outer margin is white and the middle of the forewings have white patterning. The hindwings are fully cream or have a similar gradient. The antennae of females are thin and white, while males have feathery yellow antennae. Males and females may have differing coloration. Females are larger than males.

The caterpillars are known for their long stinging hairs and their unusual amount of prolegs. Flannel moth caterpillars have 7 pairs of prolegs, while all other butterfly and moth caterpillars have 5 or fewer.

Average wingspan: 30 mm (≈1.18 in)

Diet and Habitat This species live on oak, elm, and wild plum as well as many garden plants such as roses and ivy. Adult moths do not feed.

It’s distributed across the eastern United States/Gulf Coast. They range from New Jersey to Florida and west to Arkansas and Texas. It is common in Florida but reaches its greatest abundance in Texas. They can reach further south to Mexico and Central America. They are commonly found in wooded areas like deciduous forests but can also be found in urban and suburban gardens.

Mating This moths has 2 generations per year, one in the summer and one in the fall. Late larvae may overwinter in their cocoon and emerge in late spring. Females usually mate the night of they leave their cocoons and lay their eggs during the first two nights following mating. Eggs are laid in single or double curved rows and occasionally in patches on foliage or small twigs and are covered with hair from the under side of the female to protect them. Eggs hatch in six to eight days.

Predators Observations of this moth’s predators is lacking, but there are a few reports of lacewing feeding on their eggs and a lizard eating a later instar. It is assumed they are preyed on by other common predators of moths like birds, bats, praying mantises, lady beetles, and ants. At least four species of tachinid flies and two species of ichneumonid wasp have been reported to parasitize the flannel moth larva. The caterpillar protects itself with long venomous spines. When touched they cause severe skin irritation, described as like a broken bone or blunt-force trauma, or even white hot. The reaction tends to spread:

“The reactions are sometimes localized to the affected area, but are often very severe, radiating up a limb and causing burning, swelling, nausea, headache, abdominal distress, rashes, blisters, and sometimes chest pain, numbness, or difficulty breathing. Sweating from the welts or hives at the site of the sting is not unusual.”

Fun Fact The caterpillars are covered in long setae, making it resemble a tiny Persian cat, which is where it is assumed the name "puss" comes from. Some of the many names for the larva include: puss caterpillar, asp, Italian asp, fire caterpillar, woolly slug, opossum bug, puss moth, tree asp, and asp caterpillar.

(Source: Wikipedia; IFAS Extension, University of Florida; Missouri Department of Conservation; AZ Animals)