Megalopyge opercularis

Megalopyge opercularis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Megalopygidae
Genus:	Megalopyge
Species:	M. opercularis
Binomial name
Megalopyge opercularis (JE Smith, 1797)

The moth Megalopyge opercularis has numerous common names, including southern flannel moth, pussy moth, puss caterpillar, tree asp, and, asp caterpillar. It is visually striking in both larval and adult forms. The inch-long larva is generously coated in long, luxuriant hair-like setae, making it resemble a tiny Persian cat, the characteristic that presumably gave it the name "puss." It is variable in color, from downy grayish-white to golden-brown to dark charcoal gray. It often has a streak of bright orange running longitudinally. The 'fur' on early-stage larvae is sometimes extremely curly, giving the larva a cottony, puffed-up look. The body tapers to a tail that extends well beyond the body, unlike its relative M. crispata (Wagner 2005). The middle instar has a more dishevelled, 'bad-hair-day' appearance, without a distinctive tail.

Caterpillar

Cocoon

The adult moth is also very bizarre in appearance, covered in long fur in colors ranging from dull orange to lemon yellow, with hairy legs and fuzzy black feet.

The 'fur' of the larva contains venomous spines that cause extremely painful reactions in human skin upon contact. 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 (Eagleman 2008). Additionally, it is not unusual to find sweating from the welts or hives at the site of the sting. Ironically, the resemblance of the larvae to soft, colorful cotton balls encourages people to pick them up and pet them.

M. opercularis can be found on oaks, elms, citrus and other trees, and many garden plants such as roses and ivy. It is distributed throughout the southern United States, Mexico, and parts of Central America. The larva does not spin a real cocoon, rather, it separates from its furry skin and uses it as a protective covering while it pupates.

Dangers and Treatment of Stings

Exposure to the caterpillar's fur-like spines will lead to an immediate skin irritation. The caterpillar is regarded as a dangerous insect because of its venomous spines. Medical advice may be sought in case of contact with one. It is best if the venom from the spines are treated within hours of first contact. For first aid, it is recommended that you remove the spines (if present) using cellophane tape (Eagleman 2008).

Other remedies, which are reported to have varying degrees of success, include ice packs, oral antihistamine, baking soda, hydrocortisone cream, juice from the stems of comfrey plants, or calamine lotion (Eagleman 2008).

References

• Eagleman, DM (2008), "A study of the geographical distribution and symptoms of envenomation by the Asp Caterpillar, Megalopyge Opercularis", Clinical Toxicology 46 (3): 201–5, http://neuro.bcm.edu/eagleman/papers/Eagleman%20Asp%20Caterpillar%20Clinical%20Toxicology.pdf 
• Wagner, DL (2005), Caterpillars of Eastern North America., Princeton Univ. Press 

External links

• Research on the Asp Caterpillar at Baylor College of Medicine
• Info page with photos
• BugGuide account