Fauna
Insect

Southern Flannel Moth

Megalopyge opercularis

Also known as Puss Caterpillar, Asp Caterpillar, Tree Asp, Woolly Slug

Adult southern flannel moths resemble tiny, furry mammals with thick, wavy tufts of cream-to-golden scales covering their stout bodies and wings. Their larvae, widely recognized as puss caterpillars, conceal a network of hollow, venom-injecting spines beneath a dense coat of soft-looking hair. Adults live only a few days after emerging, relying on energy stored during the caterpillar stage to mate and lay eggs on host trees.

NocturnalVenomousFurry
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Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & preyOak leaves, Elm leaves, Sweetgum leaves
Predators
  • Braconid wasps
  • Tachinid flies
  • Assassins bugs
ThreatsParasitoid wasps and flies, severe freezes, and chemical pesticide spraying
HabitatsDeciduous forests, suburban parks, mixed woodlands, and gardens
Life spanUnder 1 year total (adult stage lasts 4–7 days)
Classification
  1. OrderLepidoptera
  2. FamilyMegalopygidae
  3. GenusMegalopyge
  4. SpeciesMegalopyge opercularis
Range & activity
Range data is not available yet.
Safe observation
Interaction riskVery high
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is very high
Larval hairs conceal spines with venomous stings causing severe pain; never touch without protective tools.
Why it is dangerous
Hollow setae deliver a potent proteinaceous venom that causes radiating, throbbing pain, localized swelling, nausea, and occasional systemic reactions.
How to recognize a risky encounter
Larvae look like teardrop-shaped tufts of tan, grey, or reddish-brown fluff resting flat against tree foliage.
What to do
Do not touch, handle, or sweep against leafy branches where larvae feed; wear thick gloves when gardening under host trees.
Responsible observation
  • Viewing: Inspect broadleaf tree trunks and leaf undersides from several paces away using binoculars.
  • First Aid: Use adhesive tape immediately to lift broken spines if brushed, then apply cold packs.
Related species
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Moonlight Marvels

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