Beware Southern Flannel Moth Caterpillars With Painfully Pretty Spines

Summary: Southern flannel moth caterpillars have strong toxins in venom glands beneath hair-like, Persian cat-like bristles for the unwary summer through fall.

southern flannel moth (Megalopyge opercularis) caterpillar; Merrimac Farm Wildlife Management Area, Aden, Prince William County, Northern Virginia; Monday, Sep. 15, 2014, 05:18: Judy Gallagher, CC BY 2.0 Generic, via Wikimedia Commons

Southern flannel moth caterpillars are painful in their venomousness and pretty in their Persian cat-like coats, as a 15-year-old Floridian acknowledged after 20-plus attacks from the aggressive larva's spines June 16, 2018.

Logan Pergola of Land O' Lakes, Pasco County, bore no gloves when his bundling branches bothered a southern flannel moth caterpillar into brandishing setae (hair-like bristles). He considered the contact at 10:15 a.m. Eastern Daylight Time (2:15 p.m. Coordinated Universal Time) as "like someone was drilling into my bone and wouldn't stop." Andrea Pergola drove her son 36 minutes later to the Zephyrhills Emergency Room after garlic did not draw venom from Logan's reddened left arm and chest.

Intravenous treatments and medicine ended the experience within seven hours for Logan, who emphasized, "Wear gloves. I wasn't wearing gloves and I probably should have been."

June through August and September through November respectively function as the summer and the fall months that furnish two annual broods of southern flannel moth caterpillars.

Southern flannel moth females and males get together the first emergence night from 14-day pupal stages, or overwintering cocoons, on host plant bark, branches or twigs. Mated females have black-margined, white-based yellow front wings, creamy-yellow hindwings, orange thoraxes and short-thread-like antennae and hold 0.047-inch- (1.2-millimeter-) long, 0.024-inch- (0.6-millimeter-) wide yellow eggs. They install the round-ended eggs in one to two curved patches or rows on deciduous host plant bark, branches and twigs within two nights of mating.

Southern flannel moth life cycles juggle five to six days as eggs; 62 days as first through fifth, or six-plus, instars; and 14 days as pupae.

Arborists, master gardeners, master naturalists and tree stewards additionally know southern flannel moth larvae commonly as asp, opossum bug, puss, tree asp and woolly slug caterpillars.

The additional common names list the painfully pretty-haired larval looks of the Megalopygidae crinkled flannel moth family member of the Lepidoptera butterfly and moth insect order. Southern flannel moth caterpillars manifest ever hairier, yellower 0.059-inch- (1.5-millimeter-), 0.091-inch- (2.3-millimeter-), 0.122-inch- (3.1-millimeter-), 0.14-inch- (3.6-millimeter-), 1-inch- (2.54-centimeter-) and 1.38-inch- (3.5-centimeter-) long first through sixth instars. All instars need two proto-limb sets beyond five-set moth standards and six rows of venom glands even though only the last need 0.19-inch- (0.5-centimeter-) long tails.

The southern flannel moth scientific name Megalopygidium opercularis ("large-rumped [caterpillar, cocoon with] lid") observes pupal entrances and exits on 0.52- to 0.7-inch (1.3- to 2-centimeter) cocoons.

Southern flannel moth adults, profiled scientifically in 1797 by James Edward Smith (Dec. 2, 1759-March 17, 1828), possess 0.95- to 1.42-inch- (2.4- to 3.6-centimeter-) long wingspans.

Southern flannel moth males queue up longer, more feathery antennae, with rami ("teeth") on two sides; lower ends of size ranges; and more black than females. Citrus, elm, ivy, oak, rose and wild plum hosts sometimes retain for adults edge-fed, hole-chewed, skeletonized foliage by instars and parental silk for eggs and pupae. Hollow spines for strong toxins sustain southern flannel moth caterpillars against predation from New Jersey southward through Florida, westward through Arkansas and Texas and everywhere in-between.

Lacewings (Chrysopa); flies (Carcelia, Chetogena, Euphorocera, Lespesia), lizards (Anolis) and wasps (Hyposoter); and wasps (Lanugo) respectively tether eggs and caterpillars, larvae and pupae better than insecticides.

male southern flannel moth (Megalopyge opercularis); Durham County, north central North Carolina; Wednesday, July 14, 2004: Patrick Coin (Patrick Coin), CC BY SA 2.5 Generic, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

southern flannel moth (Megalopyge opercularis) caterpillar; Merrimac Farm Wildlife Management Area, Aden, Prince William County, Northern Virginia; Monday, Sep. 15, 2014, 05:18: Judy Gallagher, CC BY 2.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Southern_Flannel_Moth_caterpillar_-_Megalopyge_opercularis,_Merrimac_Farm_Wildlife_Management_Area,_Aden,_Virginia.jpg;
Judy Gallagher (Judy Gallagher), CC BY 2.0 Generic, via Flickr @ https://www.flickr.com/photos/52450054@N04/15133509480/

male southern flannel moth (Megalopyge opercularis); Durham County, north central North Carolina; Wednesday, July 14, 2004: Patrick Coin (Patrick Coin), CC BY SA 2.5 Generic, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Megalopyge_opercularisPCCP20040714-5799B.jpg

For further information:

Cascio, Josh. 20 June 2018. "Land O' Lakes Teen Recovering after Puss Caterpillar Sting." Fox 10 Phoenix > Health.
Available @ http://www.fox10phoenix.com/health/land-o-lakes-teen-recovering-after-puss-caterpillar-sting

Hall, Donald W. "Puss Caterpillar." University of Florida Entomology & Nematology Department > Featured Creatures > Miscellaneous > Moths.
Available @ http://entnemdept.ufl.edu/creatures/misc/moths/puss.htm

Justin. 17 June 2014. "Puss Moth Caterpillar: It's Cute, Furry, and Venomous." Nature's Poisons > Featured Poison.
Available @ https://naturespoisons.com/2014/06/17/puss-moth-caterpillar-its-cute-furry-and-venomous/

McCain, Emily. 19 June 2018. "Venomous Caterpillar Sends Boy to ER." WCPO Cincinnati > News > National.
Available @ https://www.wcpo.com/news/national/venomous-caterpillar-sends-florida-boy-to-er

O'Kane, Caitlin. 20 June 2018. "Venomous Caterpillar Sends Teen to Emergency Room with 'the Worst  Pain He Ever Felt.'" CBS News > News.
Available @ https://www.cbsnews.com/news/venomous-caterpillar-sends-teen-to-emergency-room-with-the-worst-pain-he-ever-felt/

Smith, Jacques Édouard. 1797. "Tab. LIII. Phalaena opercularis Waved Yellow Egger Moth." Histoire Naturelle des Lépidoptères Les Plus Rares de Georgie. Tome second. [The Natural History of the Rarer Lepidopterous Insects of Georgia. Volume II]. London England: T. Bensley, MDCCXCVII.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/269162
Available via Internet Archive @ https://archive.org/stream/mobot31753000314432#page/n18/mode/1up

Wine, Dan. 21 June 2018. "Florida Boy's Frightening Brush with Venomous Caterpillar Lands Him in ER." New York Daily News > News > National.
Available @ http://www.nydailynews.com/news/national/ny-news-florida-boy-venomous-caterpillar-20180621-story.html

Yadav, Satyam. 21 June 2018. "Florida Boy's Frightening Brush with Venomous Caterpillar Lands Him in ER." TechnicalFriends > News.
Available @ https://www.technicalfriends.com/florida-boys-frightening-brush-with-venomous-caterpillar-lands-him-in-er/