The Hoary Elfin (Callophrys polios)
By Zoe Melissa Simpson, Ecologist Chequamegon-Nicolet National Forest
The Hoary Elfin (Callophrys polios) belongs to the family Lycaenidae, subfamily Theclinae, commonly referred to as the “hairstreaks”. The name is given on account of the fine, hair-like markings which extend across the under surface of the hind wings. In many species, there is a tailed projection or two on the hind inner margin of the hind wing. As a group, Elfins are often the first non-hibernating butterflies to appear, flying at the first sign of spring.
The Hoary Elfin is a small butterfly with a wingspan of 7/8 to 1 and 1/8 inches (22 to 29 millimeters). Their dorsal side is unmarked and orange-brown. The ventral side is brown and the hindwing is darker brown toward the base. The underside of the forewing appears to be dusted with white along the outside edge, and is marked with a wavy line and a faint row of blackish dots. The outer half of the underside of the hindwing also appears dusted with white. This “hoary” appearance is where it derives its name. This species does not have a tail on their wings. Caterpillars are pinkish to yellow when young. When older, they are bright green with lighter green lines down back and sides, and oblique green marks on flanks. They have a white star behind their heads and can reach a half-inch long.
They prefer open areas including pine barrens, meadows, and forest edges with their larval host plants, bearberry or Kinnikinnick (Arctostaphylos uva-ursi). They may also use another ericaceous host, trailing arbutus (Epigaea repens). Adults fly April to May in the southern part of their range and May to June in the northern parts of their range. They are univoltine and females lay eggs singly on leaf buds or flower pedicels of their host plants and overwinter as chrysalids. Caterpillars feed on flowers and new growth. Adults get nectar from flowers including bearberry, leatherleaf, Pyxidanthera barbulata, wild strawberry, and willow.
This species has received a NatureServe Global Conservation Status of G5-Secure. This species is declining significantly in the eastern part of its United States range, but is thought to be stable westward and in Canada.