making friends with late-summer caterpillars

ALL TOO OFTEN GARDENERS ARE REVOLTED by the sight of a caterpillar, their immediate instinct to kill, kill, kill these seemingly voracious eaters. But how many besides the tomato hornworm or gypsy moth or Eastern tent caterpillar, for instance, do you really know by name, or can you identify by their favored diet? I’m making friends with some moths-in-the-making who are visiting me right now, happy to share a portion of the fading summer garden with some hairy little beasts in the name of a science lesson. Rather than rush to squish, how about asking who they are?

Lately I have a lot of little fuzzy black and white creatures eating the leaves of my cannas (above), which is what got me started wondering who’s who. Turns out that’s the larval form of a hickory tussock moth, I think, whose usual diet is ash, elm, oak, hickory, maple, willow, and other trees.

Though he looks velvety, look but don’t touch, apparently: The long “lashes” of the hickory tussock moth, Lophocampa caryae, are hollow tubes connected to poison glands, and can give susceptible people a stinging nettle-like rash or other reaction. The rest of the bristles, or setae, may also be irritating.

This extensive University of Wisconsin-Milwaukee article offers a full portrait of the life of the hickory tussock moth, which apparently will spend the winter in a silk cocoon under tree bark or on the ground, then eventually works its way gradually next year to moth-hood.

He’s the cousin of two other recent arrivals: a small yellowish-tan caterpillar that I think might be the Virginian tiger moth, Spilosoma virginica (above), which apparently feeds on both herbaceous and woody plants. I found this guy in my house, actually, on a piece of garden gear I’d brought inside, and relocated him to the canna leaf.  He had apparently been parasitized by some wasp or other—you can see the one egg on his rear right side that didn’t fall off when I moved him back outdoors.

Both are cousins of the familiar woolly bear or wooly worm; all three are in the taxonomic tribe Arctiini (the tiger moths). Since they’re not deforesting the entire region or anything, I’m just letting them be–and eat. We just don’t understand enough about all of nature’s tiniest creatures to go blindly rampaging against them, do we?

At this time of year, many of us start to notice the woolly bear, or Isabella tiger moth, Pyrrharctia isabella (above)—looking to see how much black versus rusty banding circles its fat, fuzzy body to try to predict the coming winter. More brown=milder; more black=more fierce, or so the idea goes. As a forecasting tool, it probably doesn’t hold up to strict science by any means, as you can read about on the Farmer’s Almanac site or Bug Guide [dot net], my hands-down favorite online resource for identifying insects, spiders and their relatives of the U.S. and Canada.

Me? I’m forecasting an early onset to winter based on equally folkloric notions, like the fact that three species of feeder birds who usually don’t bother with me again until fall properly sets in—the chickadees, nuthatches and titmice—are already hanging around looking for a meal the last week.

All efforts to ask them what’s up were met with the usual chatter, but nothing I could decode.