Uniformity of Leaf Shelter Construction by Larvae of Epargyreus clarus (Hesperiidae), the Silver-Spotted Skipper

Abstract

Larvae of the silver-spotted skipper, Epargyreus clarus (Hesperiidae), construct shelters from leaves of their leguminous host plants, making four distinct shelter types that change predictably over larval ontogeny. Shelters built by first-instar larvae are located on the apical half of the leaflet and are almost invariant in size, shape, and orientation, suggesting a stereotypical process of shelter location and construction. We have determined that the regularity of these shelters results from a prescribed pattern of larval movements and behaviors, in which larvae use their body length as a "ruler" and employ silk not only as a building material but also as a template to guide the location of cuts in the leaf. Though lepidopteran larvae lack the sensitive antennae, long jointed appendages, and other measurement devices used by structure-building bees, wasps, and caddis flies, they can nonetheless use simple tools and behavioral patterns to produce characteristic and regular shelters.