Saddleback Caterpillars

This was my first meeting with a stinging saddleback caterpillar. (Photo by Charlotte Ekker Wiggins)

This was my first meeting with a stinging saddleback caterpillar. (Photo by Charlotte Ekker Wiggins)

Saddleback Caterpillars

Watch the sting!

No, I’m not talking about honey bees, although I have those in spades in my Missouri hillside garden. This sting comes from a tiny, about an inch long caterpillar, knows as the saddleback caterpillar Acharia stimulea because of the brown saddle-like marking on its back.

I happened to brush up against one earlier this fall in my garden as I was pulling out Japanese knotweed. The spots where it brushed me left not only a painful, bee-like sting but raised round welts that lasted a couple of days. The spot on my leg where I brushed against it was also painful.

I didn’t think much about it until later as I was trying to identify this “cute” little caterpillar and came across several warnings about its sting.

We all know before we have moths and butterflies we need to have caterpillars, even one with poisonous spines. This little creature certainly has evolved to protect itself; it has spines all over its body and both ends are marked as heads to throw off aggressors.

Another look at a saddleback caterpillar in my garden. (Photo by Charlotte Ekker Wiggins)

Another look at a saddleback caterpillar in my garden. (Photo by Charlotte Ekker Wiggins)

The saddleback caterpillar measures about an inch long. It has poisonous spines on four large projections (tubercles) and many smaller ones projecting from the sides of its body. This is not a caterpillar you will want to pick up with your fingers.

The saddleback caterpillar is a general feeder and is found on many plants including apples, asters, blueberries, citrus, corn, dogwoods, elms, grapes, linden, maples, oaks, Prunus species, sunflowers, and viburnums. My garden must be a veritable smorgasbord for them with a couple of exceptions.

The saddleback caterpillar is the beginning of what will become a fuzzy, dark brown moth, which I periodically see around my decks at night. The males show up early evening; the females later at night. Moths are part of our wonderful diverse population of pollinators.

It takes the caterpillar about 5 months to evolve into a moth. I’ve spotted a couple of places in my garden where there is a cocoon under some leaves but I’m going to leave them. Better the fuzzy moth than the prickly caterpillar!

Charlotte