Camouflage revealed

Early fall finds most naturalists outside in fields of waist-high wildflowers. This was the case recently when a few Lake County Forest Preserves Environmental Educators stumbled across a miniscule critter with mighty camouflage capabilities. So small and inconspicuous, it was almost dismissed entirely as merely a part of the black-eyed susan flower (Rudbeckia hirta)—until it started to move.

Look very closely at this photo and you can see how this camouflaged looper caterpillar (Synchlora aerata) doesn’t merely blend in with the flower, but in a way, literally becomes part of the flower itself. This little larva spends its days chewing off pieces of its host plant (yellow petals in this case) and pasting them onto its back. As the petal fragments pass through the larva’s mouth, a mucous-like substance is secreted which acts like Super Glue. Even when the disguise is complete, maintenance is required to keep up the ruse. Old and damaged plant tissues are eaten or discarded, replaced and extra mucous is added. Although the plant’s pollen provides the caterpillar’s chief food source, these bits of plant tissue also provide nourishment.

In this bird’s eye view, you can see just how effective this sophisticated camouflage can be, especially when it comes to winged predators. What is even more amazing is that this larva can actually “change its costume” when moved to a different host plant, such as a white boneset (Eupatorium spp.) or a purple New England aster (Aster novae-angliae).  Thus, this critter’s camouflage capabilites are not restricted to a specific host plant or color. They can gorge themselves in plain view while exploiting a number of potential plants for food and cover.

A camouflaged looper caterpillar will keep the plant materials attached to its exoskeleton until it molts, only to start the process of chewing and pasting again with each subsequent shedding of its outer covering. The partially grown larva overwinters and completes its metamorphosis in the spring to reveal its adult form—the wavy-lined emerald moth. Adult moths are nocturnal and are attracted to light. You may have seen this beauty fluttering around a porch light.

Consider taking some time this fall to scour the fields for these fascinating masters of disguise. Join a naturalist at a Lake County Forest Preserves Families Exploring—Field Insects program to net and view what’s crawling and jumping in the tall grasses. Or take a Walk on the Wildflower Side to uncover the secrets of autumn wildflowers.

9 thoughts on “Camouflage revealed

  1. I think I’ve seen these caterpillars but din’t know what I was seeing. I just thought it was an odd mutation that there were a few ray flowers in the middle of a disc. I will be looking much closer in future and I will be passing the information on in the McHenry County Acorn newsletter.

  2. Our neighbor gave us a bundle of black eyed susan’s from her garden and we found one on the flowers. We have been keeping watch over the past few days watching it slowly change its disguise. Quite interesting to watch. We saw it had added the yellow petals to its body yesterday but today it seems to either stay in one spot just under the head of the flower on the steam or completely removed everything in one spot and is walking around exposed. I’m not sure what has happened over night but I will keep an eye out.

  3. I do a lot of macro stereoscopic(3d) photography and came upon one of these in Somerville, Massachusetts and had no idea what it was until now. I hope to post a picture of one soon

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