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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Now you see ‘em, now you don’t: Silver spotted skipper caterpillars, Epargyreus clarus


Silver spotted skippers are one of most rambunctious pollinators in the garden.


A young silver spotted skipper larva hides in a rolled leaf margin.

Every magician has at least one disappearing act in his or her bag of tricks and so do many insects, including the larvae of moths and butterflies. Recently while on a suburban safari I discovered several leaves of a black locust tree folded over at the edge. After unrolling the leaf, I was delighted to see a pencil-necked, purple-headed caterpillar hiding in the fold. This was the larva of the silver spotted skipper. These caterpillars eat the nutritious leaves of black locust, false indigo and other leguminous hosts, including soybeans.  

Rambunctious silver spotted skippers present a flash of silver on the underside of their wings as they seek nectar and pollen from a wide variety of blossoms in shades of blue, red, pink, and purple. Nutrients from nectar and pollen are converted into eggs that female butterflies deposit on the leaves of black locust and other hosts. Small caterpillars hatch from the eggs and, using silk and skill, each folds the edge of a leaf and hides within the fold. From their protected bivouacs the caterpillars sally forth to eat tasty sections of leaves. As larvae grow, whole leaves may be webbed together and other leaves nearby disappear into the bellies of the growing caterpillars. Mature caterpillars pupate and in time adult butterflies emerge from the chrysalises.



A silver patch on the underside of its wing is enough to identify the silver spotted skipper as it dashes among the blossoms.  

Unfolding the silk-bound leaves reveals the bizarre caterpillar.

Fully grown larvae are crazy looking creatures with two large yellow spots at the front of their deep purple heads. These false eyespots may be a ruse to help fool would-be predators. One can only imagine that a predator such as a small bird or lizard, confronted by a yellow-eyed purple-headed creature, might reconsider and choose to seek a meal elsewhere. The caterpillar’s true eyes are small and unimpressive. In a few months’ time, during the last days of autumn, the final generation of caterpillars completes development and form pupae to withstand winter’s cold. With the return of warmth and locust leaves next spring, butterflies emerge to sip nectar and find new leaves to serve as food for their young.


A large purple head and two bright yellow eyespots might be just enough to scare away a hungry predator.




A large silver spotted skipper larva has webbed together two leaves.

The rolling, folding, and cutting of leaves is a trick employed by many species of moths and butterflies, including the spicebush swallowtail caterpillar we met in a previous episode. By hiding within rolled leaves or those held together by silk, caterpillars may be less easily found by hungry predators like birds or parasitic wasps as they search for tasty meals and juicy hosts in which to rear their young. Next time you see a folded or rolled leaf on a tree or shrub take a moment to unfurl the foliage and see who just might be hiding inside.   




To learn more about the silver spotted skipper, please visit the following web site: