Creature Feature: Hoary Edge

By Ezra Staengl, Center for Urban Habitats

Hoary Edge

Achalarus lyciades

Family: Hesperiidae

Other common names: Hoary Edge Skipper

 

A hoary edge butterfly skipped through the air, the bright midday sunlight flashing off its white hindwings. It alighted gently on a small clump of hairy thoroughwort flowers which were just beginning to open for the year. The thoroughwort buzzed with the wings of other butterflies, as well as countless bees and wasps. The hoary edge unfurled its proboscis and began to drink nectar from the thoroughwort. A couple feet away, I bent closer to take a photo.

Distinguishing Features/Description:

The hoary edge is a large and strikingly marked skipper. From the upper side, they are mostly brown with one large golden band on each forewing and some golden checkering along the trailing edges of the hindwings. From below, the trailing edges of the hindwings are covered in a broad frosty white band (the color referenced by the word hoary), from which the butterfly gets its name. Caterpillars are green, spotted with orange and white, and with a brown head.

Although distinct upon close inspection, the hoary edge is superficially similar to several other species of large skippers, particularly the ubiquitous silver-spotted skipper. Silver-spotted skippers have white bands in the middle of their hindwings, rather than on the outer edges. Other superficially similar species include several species of cloudywings and duskywings; however, these butterflies lack the bold orange and white markings shared by hoary edges and silver-spotted skippers.

Hoary Edge. Photo by Ezra Staengl

Distribution and Habitat:

The hoary edge is widely distributed throughout eastern North America, from Texas and Oklahoma east to the coast and from northern Florida north to New England. Hoary edges become much less abundant towards the northern extreme of their range, though. In Virginia, hoary edges are uncommon but fairly reliably found in their preferred habitats of partially shaded but open woodlands and savannas.

Ecology and Life History:

Hoary edge caterpillars feed on several genera in the pea family (Fabaceae), including tick-trefoils (Desmodium sp.), bush clovers (Lespedeza sp.) and wild indigoes (Baptisia sp.). All these genera are heliophytes, meaning they require high sun exposure and are thus strongly associated with grassland plant communities. Adult hoary edges nectar on grassland plants as well, including thoroughworts (Eupatorium sp.), milkweeds (Asclepias sp.), and new jersey tea (Ceanothus americanus).

In most of their range, hoary edges fly from April to September, during which time they have two broods. In the extreme north of their range their flight time is shorter, and they only have one brood per year (A Swift Guide to Butterflies of North America, 2017). Caterpillars of the second brood overwinter in leaf litter (Caterpillars of Eastern North America, 2005). Adult males look for females from perches in woodland clearings (Hoary Edge Achalarus Lyciades (Geyer, 1832) | Butterflies and Moths of North America, n.d.).

References