BEWARE! Flannel Moth Caterpillar

Guests frequently drop by BioWorks with “mystery bugs” for us to identify. Not too long ago, I answered a knock at the lab door and found a boy and his mom, holding this caterpillar and looking for an ID.

 
My immediate thought was: “DON’T PANIC. You don’t want to scare this boy and his mom!” You see, I was pretty sure that the fuzzy little caterpillar he was holding so precariously on a small jar lid was in fact one of the most toxic caterpillars out there – the Flannel Moth Caterpillar (Megalopyge opercularis), also sometimes called the Puss Moth or Puss Caterpillar. Lurking in those hairs covering the body are spines that inject venom upon the slightest touch.

The first symptom of a Flannel Moth caterpillar sting is most frequently described as “searing pain”. The pain radiates up from the sting site and can cause nausea, swelling, vomiting, chest pains, and other horrifying-sounding symptoms. In severe cases, the victim may begin to experience difficulty breathing and will need to seek immediate medical attention. There’s no antidote for this sting – the only thing you can really do is apply appropriate first aid and wait it out.

Risk-takers that we are, we decided to keep this caterpillar in a tank in the lab and try to raise it to adulthood, as the adult moth is very unusual and completely harmless. We are feeding it live oak, the most common host plant, and handling it only when absolutely necessary, wearing gloves and taking all possible precautions.

 A face only a mother could love?

Children are often the victims of this caterpillar, since it looks so soft and inviting to pet. Other toxic caterpillars, like Io Moths and Saddlebacks, are just as toxic but their bright colors provide better warning. We’re relieved that the local boy who found this creature wasn’t stung. He was very lucky, since even the slightest contact is said to cause extreme pain. Fortunately, now he’ll know what to look out for, and so will you.