Biomedical Ephemera, or: A Frog for Your Boils

Southern flannel moth - Megalopyge opercularis

Also known as the “puss moth” or “tree asp” (for its luxurious-looking “fur” and its extremely painful sting, respectively), Megalopyge opercularis is a deceptively cute tribble of a caterpillar found in the Eastern and Southern United States. It’s most common in Texas, but can be found along the Eastern Seaboard as far north as New Jersey.

Both the adult and juvenile forms of M. opercularis have urticating (itch-inducing) hairs on their body, much like some other caterpillar species, but the asp takes it one step further, and has clusters of venom-filled spines under its hairs.

As they most often live in popular shade trees, caterpillars occasionally lose their grip and tumble down onto unsuspecting humans just trying to have a nice day at the park. Their reproductive cycle means they’re particularly abundant in late spring/early summer and mid autumn. The sharp spines pierce the skin and automatically inject venom for as long as they’re embedded in the skin. Unlike with snakes, the caterpillars have no control over whether or not the venom is used.

Despite their relative abundance, especially in Texas and Louisiana, many doctors and first responders wouldn’t know the signs of an asp encounter if it crawled out of Donald Trump’s (clearly asp-inspired) toupee and stung them on the nose.

Most patients (but not all) experience extreme pain at the location of the sting, and that pain often radiates to the nearest lymph nodes. Swelling occurs at the sting in a raised halo, which then recedes to show the pattern of the spines on the caterpillar (lower image). While the pain rarely lasts longer than 48 hours, some patients may experience lymphadenitis (swelling of the lymph nodes) for up to a week.

So what do you do if you’re unfortunate enough to directly encounter a tree asp?

Step 1: Cellotape! Or scotch tape, whatever you call it. Take a strip of it, put it over where the asp landed/got squished/you had the bad idea to pick it up. Remove it. Repeat several times. This helps get out any spines (which can be near-invisible) stuck in the skin. Protip: This is also useful if you ever fall into a cactus. Believe me. I’d know.

Step 2: If the pain is super intense, see a doctor. Bring with them any information about the bug that you can, but maybe don’t bring the actual caterpillar unless you have a way of handling it without getting stung again. If it’s just really bad (no, seriously, these things can bring grown men to their knees), take some anti-inflammatory drugs (such as ibuprofen or tylenol), some anti-histamines, or both.

Step 3: Wait. Sorry bud, this next day or two is gonna suck. Ice the area if you want, to numb it up. Have a beer. Eat some ice cream. Watch a movie. Try not to think about it.

If you have any trouble breathing or seeing or any other serious symptoms go directly to the emergency room. Tell them what stung you. They might not know what to do off the top of their head, but they have resources!

Read More:

Puss Caterpillar (Larva), Southern Flannel Moth

Images:

Wikimedia Commons

The Puss Caterpillar and the Effects of its Sting on Man, USDA Circular 228. F. C. Bishopp, September 1923.

Atlas Moth (Attacus atlas)

The Atlas moth is the largest moth in the world (measuring over 10 inches across), but that doesn't mean it's long-lived; once it emerges from its cocoon, its sole purpose is to breed - like many butterflies and moths, it doesn't even have a mouth! After about a week outside the cocoon, they die.

De uitlandsche kapellen: voorkomende in de drie waereld-deelen Asia, Africa en America. Pieter Cramer and Caspar Stroll, 1779.

Atlas Moth on Wikimedia Commons

Giant larva of the rhinoceros beetle of British Guiana

The most common rhinoceros beetle (subfamily Dynastinae) in British Guiana (now Guyana) is the elephant beetle (Megasoma elephas). The larval stage of these beetles can last up to 3 years, where the grubs consume the organic matter of the decaying logs that they're hatched inside.

This species is one of three beetles that was used by the Pentagon to develop their so-called "bionic beetle", which has been a bizarre and interesting project. Its outcomes so far have benefited science far more than the military, because, well, it turns out that remote-control beetles are pretty easy to see. Also...they're remote-control beetles. But hey, science! We've learned a lot from them!

Tropical Wild Life in British Guiana, Vol 1. William Beebe, 1917.

The Giant Amazonian Centipede - Scolopendra gigantea

Like the other members of Scolopendra, the giant Amazonian centipede is predatory and venomous. The first body segment has a pair of modified legs terminating in sharp claws, called forcipules (you know, like forceps), which it uses to pull its prey to its mouthparts, where it injects its venom.

Though typically non-fatal to humans (excepting those allergic to the venom toxins), giant centipede bites are incredibly painful and can cause symptoms for days on end. This venom is what allows them to hunt prey as large as small mammals and birds, without itself being eaten.

I have no idea what people are thinking when they buy one of these, but they're apparently a big thing in exotic insect circles. They're known to be jumpy, nervous, and very aggressive both in the wild and in captivity, and can often escape enclosures that aren't well-sealed. I mean, come on. Even tarantulas can be docile and friendly. And mantises are fun to watch and not venomous! And there are so many other options! Why a giant centipede?

Vivarium Naturae; or, the Naturalist's Miscellany. George Shaw, 1790.

Red Locust (Nomadacris septemfasciata)

The red locust is a sub-Saharan grasshopper in its gregarious phase. Unlike desert locusts, red locusts have not caused any devastating crop destruction since the 1940s. However, the last mass gregarious infestation lasted from 1930-1944 in Chad, the Sahel, and almost all of southern Africa, and was as devastating as the Rocky Mountain locust was in the United States in the 19th century.

Fabre's Book of Insects. Illsutrated by E. J. Detmold, 1921.

Ornithoptera victoriae - Queen Victoria's Birdwing - Adult, Caterpillar, and Egg

This butterfly is a close relative to the largest butterfly in the world, Queen Alexandra's Birdwing. The birdwing genres are noted for their bird-like flight, angular wings, bright colors, and exceptional size.

Like many Lepidoptera (the order containing moths and butterflies), their caterpillars are toxic, owing to the plants they consume, and are not commonly  eaten in their natural habitat. The butterflies retain this toxicity through adulthood.

Proceedings of the General Meetings for Scientific Business of the Zoological Society of London. 1888.