More than any other, the caterpillars of Monarch butterflies are most closely associated with eating milkweed–anything in the Asclepias family. With their distinctive black, white and gold pin-striped suits and expressive dark tentacles reaching out into the universe, that’s no surprise.

Monarch caterpillar on milkweed

Monarch butterfly caterpillar on milkweed, its host plant. Photo by Monika Maeckle

They’re endearing, ubiquitous, easy to identify and we have a special relationship with them.  But there’s a at least three other caterpillars that eat milkweed for breakfast, lunch and dinner.

Last week I noticed this fellow noshing on a pot of Swamp milkweed, Asclepias incarnata.

My first thought: “That ain’t no Monarch.”

Correct. It’s the Striped garden caterpillar, Trichordestra legitimata, which feasts not only on milkweed but other common garden greens–clover, goldenrod, yarrow, grasses and others. The Striped garden caterpillar turns into the rather nondescript Striped garden caterpillar moth, a grey, smallish creature with little black diamonds on his back. Check out these photos on Bugguide.net.

Here’s a better picture of the caterpillar, via Molly Jacobson.

Garden striped caterpillar

That ain’t no Monarch. It’s a Striped garden caterpillar. Photo by Monika Maeckle

Molly Jacobson found this Striped  garden caterpillar crossing a path and resting on a dead leaf. Photo by Molly Jacobson

Dr. David L. Wagner, author of the useful Caterpillars of Eastern North America, describes the milkweed feeder on page 415 of his seminal guidebook as a “handsome brown and yellow striped caterpillar.” He recommends looking for them in grass seed heads but adds that he often finds them on the flowers of Goldenrod in the fall.

Perhaps even more handsome is the fluffy Milkweed Tussock Moth caterpillar, Eucaetes Egle. Like so many other insects that use milkweed as their primary food, this creature expresses the cardiac glycosides found in the latex of the milkweed plants with orange and black coloring.

This Tussock moth caterpillar was spotted in Glen Rose, Texas in 2007 walking across a hiking trail in a wooded area. Photo by J. Scott Kelley via Wikipedia.

Milkweed Tussock Moth, photo by Patrick Coin via Wikipedia.

The adult form of this moth, below, also displays orange and black on its body, as it peeks through the wings to alert predators–WARNING: I don’t taste good!

Dr. Wagner’s description of the interesting larvae: “densely hairy caterpillar with numerous black, orange (or yellow) and white tufts and lashes.” Yes, “lashes.”

That’s what these hairy protrusions look like–almost colorful bristles on a soft toothbrush extending from the caterpillars body. According to Wagner, the species occurs in Texas and the Southwest, but I have never seen one. Would love to, though.

A third milkweed fan, Cycnia inopinatus, also makes appearances now and then. Kip Kiphart, a trainer for Monarch Larvae Monitoring Project (MLMP) and volunteer at Cibolo Nature Center in Boerne, Texas, reports that the Cycnia pictured below was found in 2003 by Myrna Langford while checking milkweed on Laurel’s Ranch near Comfort, Texas.  The Cyncia is considered a first for the area.

Kiphart says Langford brought the caterpillar to a meeting, asking for help in identifying it. “Nobody had any idea what it was. I took it home, took photos, sent them to a number of people and nobody knew what it was,” said Kiphart. Eventually the Cyncia was identified.

It turns into the Unexpected Cyncia moth and feeds exclusively on milkweed. You can see the same orange-and-black expression of other milkweed consumers in the belly of the beast, below. The University of Minnesota, which oversees the MLMP, is seeking citizen science observations and documentation of the moth, which is considered rare and of conservation concern.

Cyncia inopinatus caterpillar. Another milkweed feeder. Photo by Kip Kiphart

Cyncia adult moth. Photos by Kip Kiphart

Cynic

Judging from conversations with folks who work and play a lot with milkweed raising caterpillars and butterflies, these other milkweed eaters are not all that common.

Have you seen any of these other milkweed feeders? Let us know.