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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.

Hocus-pocus: Silver spotted skipper, Epargyreus clarus


Adult silver spotted skippers are regular visitors to the garden


Every magician has at least one disappearing act in their bag of tricks and so do many insects, including the larvae of moths and butterflies. In midsummer, I discovered several leaves of my black locust tree folded over at the edge. I suspected the work of a master of disguise. After unrolling the leaf, I was delighted to see a small green caterpillar with a pencil-neck and purple head. This was the larva of the silver spotted skipper, and these caterpillars eat nutritious leaves of black locust trees, much like the locust leafminers we met in “Scorched locust - Locust Leafminer." Skipper larvae hatch from tiny eggs deposited on leaves by adult silver spotted skippers. This rambunctious small butterfly with a flash of silver on the underside of its wings eats nectar and pollen throughout the summer. 

Young silver spotted skipper larvae hide in rolled margins of leaves.


It is a regular visitor in my garden, where it favors blossoms in shades of blue, red, pink, and purple. Nutrients from the nectar and pollen are converted into eggs that female butterflies deposit on the leaves of black locust trees, among other hosts. Small caterpillars hatch from the eggs and, using silk and skill, fold the edge of the leaf inward and hide in the fold. From this protected bivouac, the caterpillars sally forth to eat tasty sections of leaves. As the larvae grow, whole leaves may be webbed together, and those nearby disappear into the bellies of the growing caterpillars. The caterpillars eventually pupate, and later adult butterflies emerge from the chrysalides. Just a few weeks ago, I discovered a large skipper caterpillar hiding within two leaves held together by silk. 

Large silver spotted skipper larvae web together entire leaves.


Fully grown larvae are crazy looking creatures with two large yellow spots on their deep purple heads. These false eyespots may be a ruse to fool would-be predators. The caterpillar’s true eyes are small and unimpressive. In the last days of autumn’s waning warmth, the final brood of these caterpillars with burgundy and gold heads complete 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. What is the hocus-pocus about? By hiding within rolled leaves or those held together by silk, the caterpillars may be less easily found by hungry predators like birds or parasitic wasps as they search for tasty meals and likely hosts. Presto-change-o, now you see them, now you don’t!


Silver spotted skipper larvae are crazy looking caterpillars with two yellow spots on their head.


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