Family Hesperiidae

Skippers

The Hesperiidae are a large family of butterflies with about 3,700 species world-wide and about 300 in North America, of which 72 have been recorded in Canada. Most are small or medium sized. They are distinct in appearance from other butterflies, with a thick, heavily muscled thorax and seemingly small short wings. All have six fully functional legs in both sexes. The head is wide and the antennae arise far apart; the antennae are also very distinctive. In Canada, all species have the antennal club curved outward towards the tip, and in most a pointed extension, the apiculus, angling sharply outward beyond the club. Their flight is usually powerful, although only a few have migratory tendencies. They tend to "skip" from place to place with extremely rapid wing movements. Most have dull colours, brown or grey, and are often confused with moths by non-naturalists.

Skipper eggs tend to be more or less hemispherical in shape, with surface sculpturing ranging from very fine, almost invisible, to marked vertical ridges. Larvae are plain, unornamented, smooth or with very short hairs, cylindrical or tapered at both ends, with the last segment often divided into two "tails". They have large heads, made more noticeable because the prothorax is narrow and has the appearance of a neck. They live in silk-lined leaf-nests on the foodplants, made by cutting and folding leaves or by pulling together several leaves. Because of this and their usually nocturnal feeding habits they are difficult to find, especially the grass-feeding species. Pupation takes place in the leafnest or in a silk-lined nest in the leaf litter near the base of the foodplant. Pupae tend to be quite rounded and smooth, with the tongue more noticeable than in other butterfly pupae.

The family is divided into six subfamilies, of which four are found in North America and three in Canada.

Subfamily Pyrginae (Pyrgine Skippers)

World-wide, about one-third of all skippers are pyrgines, and Canada is typical in this respect with 24 species. Pyrgines are not as drastically different in most adult characteristics as our other subfamilies; their appearance is somewhat intermediate between skippers and other butterflies. Only the antennae are obviously distinct, with curved, banana-shaped clubs and sharply angled apiculi.

Almost all of our species are dark brown or grey, with relatively indistinct mottled patterns, often with small groups of white or translucent spots. In some species males have dark patches of scent scales, androconia, which are difficult to see against the often dark grey background. In others the scent scales are contained in a folded over section of the forewing costa.

The larval foodplants of the pyrgine skippers include a wide variety of dicotyledonous plants, in Canada most often in the families Salicaceae, Fagaceae, Fabaceae (= Leguminosae), and Malvaceae. The different habitat requirements of the foodplants are often a help in distinguishing pairs of look-alike species, which otherwise may require genitalic dissection to verify identification.

Genus Erynnis Schrank, 1801 (Duskywings)

This large genus of medium-sized skippers has 17 species in North America, and more in the Old World; 13 are known from Canada. All are dark brown in colour, usually with hoary grey scaling on the forewings, diffuse yellow spots on the margin of the hindwings, and a number of small white or translucent marks on the forewings. Apart from these markings, the wing patterns are in slightly lighter or darker shades of grey. The males of most species have part of the forewing costa folded over, protecting the stigma. Males of Erynnis icelus, zarucco, funeralis, persius, lucilius, afranius, and baptisiae have a hair plume (a tuft of long hairs) on the hind leg. This helps in distinguishing icelus from brizo, and zarucco from horatius, and in recognizing the four species of the persius group.

Duskywings are often difficult to identify, and sometimes require confirmation by examination of the genitalia. This is especially true if specimens are in poor condition or if a significant range extension is suspected. In Canada, a careful check of the range maps of each species usually reduces the number of options considerably, so examination of the genitalia is rarely required.

The foodplants are always dicotyledons, usually in the families Salicaceae, Fagaceae, Rhamnaceae, and Fabaceae. The larvae live in solitary leaf-nests on the foodplant, and hibernate as partly grown larvae. They are stout, sluggish, and covered with fine bumps or tubercles.

Unlike most skippers, duskywings usually land on the ground rather than on plants. They have a characteristic pose when they alight on the ground or on a large branch or rock: the wings are held below the horizontal position, so that they appear to be pressed firmly against the surface. This can be seen from a considerable distance, identifying the specimen as an Erynnis long before any markings can be seen. When they roost, on a twig or a flowering plant, they often wrap their wings down and partly around the twig.

Subfamily Heteropterinae (Intermediate Skippers)

This small subfamily has only one Canadian representative, the Arctic Skipper. Members of this subfamily lack the apiculus on the antenna and bask with their wings at a forty-five-degree angle. Foodplants are grasses.

Subfamily Hesperiinae (Branded Skippers)

Forty-seven Canadian skippers belong to the subfamily Hesperiinae. Branded skippers are usually small and orange brown in colour. Their relatively large bodies and small wings make them immediately recognizable as a group, but species identification can be difficult and the group is often ignored by novice collectors for this reason. Compounding the difficulty in identification is the fact that the sexes are usually distinct in appearance. Males have a dark "brand" of scent scales on the forewing, but the female pattern is different in other ways, often with expanded dark areas. Sometimes the only way to associate females with males of their species is by the hindwing underside pattern; this cannot usually be seen until the specimen is caught because of the basking position of the butterflies in this subfamily. Branded skippers hold the hindwings horizontally, and the forewings almost vertically.

Most branded skippers have a series of rows of spines along the side of the middle section of the legs (the tibia), sticking out from the leg scales; these spines are in addition to the long pair of scaled "spurs" at the end of the middle leg and the two pair of "spurs" at and near the end of the hind leg. These spines are absent in the pyrgine skippers (subfamily Pyrginae). Within the branded skippers the loss of these spines in some groups can be helpful in making identifications. The spines may be lost from the hind legs (e.g., Oarisma), from the middle legs (e.g., Euphyes), from the front and hind legs (e.g., Thymelicus), or from all three legs (e.g., Ancyloxypha). The lack of spines on the middle tibia is the most reliable way to separate females of Euphyes vestris from those of other similar species (e.g., Wallengrenia egeremet).

The larval foodplants are monocotyledons, grasses and sedges. The difficulty of identifying grasses and of finding larval nests among literally millions of grass stems has resulted in relatively little work being done on the foodplants of most species. Most have very definite habitat preferences and therefore probably foodplant preferences, but only a few foodplant species have been identified and most reports state that larvae will eat many grasses in captivity. There are very few foodplant records for Canada; this area is wide open for research.

Genus Hesperia Fabricius, 1793 (Branded Skippers)

This large genus of skippers has about 20 North American species, of which 11 have been found in Canada. One, Hesperia comma, is found from western Europe to eastern Asia and from coast to coast in North America. Many of its numerous subspecies have previously been considered to be separate species, and other species have been considered subspecies of comma; we treat two traditional "subspecies" as full species, and almost certainly other changes will be forthcoming as research on this complex genus continues.

Hesperia are medium-sized skippers, easy to recognize as a group but hard to separate into species. In Canada most are orange brown in colour (females of a few species are brown), with long pointed forewings and a short apiculus (the "hook" beyond the club) on the antennae. Almost all species have a curved medial band of pale spots on the hindwing underside, which is useful in distinguishing species. The males have a long, slender, slightly curved black stigma on the forewing, which is raised a little above the surface of the wing. The contents of the stigma of most species are black, but in two Canadian species they are yellow; the colour can be seen by gently running a fine pin through the stigma and examining the scales that rub off onto the pin tip. In addition to the characters given in the species diagnoses, there are also genitalia differences between most species.

The foodplants of all species are grasses. The larvae live singly in leaf-nests near the base of the plants, and hibernate in the nests or in nearby leaf litter. Probably all species are restricted in nature to one or just a few grass species, despite the fact that they will eat many species in captivity. Most species have one generation per year in Canada, except nevada, which may have two, and comma, which in the northern part of its range appears to have a biennial life cycle, being common only in even-numbered years from Manitoba eastward and in odd-numbered years in the northwest.

In the east the ranges of three species (Hesperia sassacus, comma, and leonardus) overlap; these are not difficult to distinguish, and in the north only comma occurs. Canadian identification problems fall into two groups of look-alike species. In the southern Prairies the ranges of ottoe, dacotae, leonardus pawnee, and assiniboia overlap; all four have undersides that are pale, with the medial spot band reduced or absent; even the uppersides usually look faded and washed out. The second group consists of six species (uncas, juba, comma, colorado, pahaska, and nevada), whose undersides are dark, with contrasting medial spots. Four of these occur in the southern Prairie Provinces and four in southern British Columbia.

Hesperia comma occurs with almost every other Canadian species, as well as northward into the Subarctic, far beyond the range of any other species. The first step in identifying these skippers is to check the distribution maps, which will usually limit the possibilities to a few species in any one area.

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.