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A Snapshot of Butterfies in Southeast Manitoba Part 10

Grass Skippers (Subfamilies Heteropterinae and Hesperiinae)

By Peter Taylor

Arctic Skipper (174 reported)
Least Skipperling (83 reported)
European/Essex Skipper (2501 reported)
Pepper-and-Salt Skipper (43 reported)
Common Roadside Skipper (57 reported)
Common Branded Skipper (6 reported)
Leonard’s Skipper (29 reported)
Indian Skipper (22 reported)
Peck’s Skipper (59 reported)
Tawny-edged Skipper (47 reported)
Long Dash Skipper (178 reported)
Northern Broken-Dash (18 reported)
Sachem (1 reported)
Hobomok Skipper (278 reported)
Broad-winged Skipper (8 reported)
Dun Skipper (1314 reported)

The grass skippers are a large subfamily with over 2,000 species worldwide, so called because the larval food plants are various grasses and sedges (also palms for some tropical species). They are also known as branded skippers, because males have a dark “brand” (patch of blackish scales) on the forewing that releases pheromones to attract females. Twenty species have been recorded in SE Manitoba, of which 15 were reported in our study. This article also includes the Arctic Skipper, which belongs to a separate subfamily.

Above: Photo 1. Broad-winged Skipper, a Manitoba rarity, in “jet-plane” posture, highlighting the left forewing and right hindwing. Photo near Pinawa on August 3, 2008 by Peter Taylor

Most grass skippers are small but relatively heavy-bodied; they often perch with forewings and hindwings held at different angles in what has been dubbed the “jet-plane position” (see Photo 1). Small size and rapid, erratic flight make them difficult to follow when flushed. They can be seen nectaring (often mingling with larger butterflies), visiting mud puddles or moist gravel, or perching on low shrubby and herbaceous vegetation. The larvae typically feed at night within a silk-and-leaf shelter at the base of a sedge or grass clump, where they may also overwinter and pupate. The larvae of one variety, the Assiniboine race of Common Branded Skipper, have been reported to form silken burrows under dried cowpats, perhaps to avoid being trampled or accidentally eaten. Different grass skippers overwinter as partly grown or mature larvae or as pupae. All appear to have a single annual generation in our region.

As well as small size and flighty behaviour, many skippers have plain coloration, with various combinations of tawny-orange to blackish brown markings, sometimes with a few clear or whitish spots. This makes identification of photographs or specimens, let alone live insects, a challenge.

Above: Photo 2: Arctic Skipper in spread-winged posture near Pinawa on June 10, 2019 by Peter Taylor.

Few grass skippers emerge before the end of May. In forested regions, where they frequent trail-sides and clearings, the Arctic Skipper and Hobomok Skipper are among the first to appear. The Arctic Skipper is more slender-bodied than the branded skippers, and relatively easy to identify by its rather fritillary-like markings it does not adopt the jet-plane posture, but may perch with wings either fully spread or closed (see Photo 2). So tiny and fast-moving is the Common Roadside Skipper, it is easily overlooked or mistaken for a fly, while its relative the Pepper-and-Salt Skipper is barely more conspicuous. Another early flyer is the Indian Skipper, an uncommon resident of forest clearings, mostly in the eastern half of our region.

Above: Photo 3: Another jet plane! A Long Dash Skipper visits a Self-Heal flower head. Photo near Culver, Manitoba on July 3, 2019 by Peter Taylor.

Many grass skippers are at their peak from late June through July, with identification challenges aplenty, for example trying to separate the various colour morphs of Long Dash Skipper (see Photo 3) from Peck’s Skippers or worn, late-flying Hobomok Skippers. At this time, it is important to know the European or Essex Skipper, an unfortunate introduction that can become a pest in Timothy grass fields. It is also widespread along roadsides in both forested and agricultural areas, especially where weedy alfalfa provides a nectar supply (see Photo 4).

Above: Photo 4: A dozen European Skippers, part of a swarm nectaring on a roadside alfalfa patch. Photo near Hadashville on July 11, 2013 by Peter Taylor.

This species accounted for just over half of our grass-skipper records, making it a special challenge to detect the similar-looking Least Skipperling, which is usually found in waterside vegetation. We found the Dun Skipper to be the most numerous native species, and it was also the least variable in numbers from year to year. This uniformly dark skipper is an avid nectar feeder and a relatively late flier, peaking in mid to late July (see Photo 5).

Above: Photo 5: A male Dun Skipper imbibing Canada Thistle nectar. Photo near East Braintree on July 30, 2008 by Peter Taylor.

Though widespread and flying through much of June and July, the Tawny-edged Skipper proved fairly difficult to find, small size and zippy flight again making detection difficult. The Common Branded Skipper is a widespread species, native to Eurasia and NW Africa as well as North America, but was scarce in our survey with totals of only two records and six individuals.

Among the rarer skippers we found were Leonard’s Skipper (see Photo 6; mostly in areas west of Bissett between late July and mid-August), Northern Broken-Dash (a challenging newcomer to the province, difficult to distinguish from other dark skippers), and Broad-winged Skipper (extending its range a little from the original discovery near Red Rock Lake in the Whiteshell). A Sachem was detected by Richard Staniforth on July 11, 2015, furnishing just the third provincial record for this migratory species – remarkably, all three were found in the East Braintree area.

Above: Photo 6: Leonard’s Skipper, a special find at a thistle patch; photo near the Wanipigow River on August 17, 2016 by Peter Taylor.

Five prairie-dwelling skippers, all known to occur in SE Manitoba, were not detected by us or our correspondents. The provincially endangered Poweshiek Skipperling is restricted to small vestiges of tall-grass prairie near the Minnesota border, and is the subject of ongoing research and conservation efforts. The much more widespread Garita Skipperling has occurred in the past as far east as Agassiz Provincial Forest; prior to this five-year survey, one was found at West Shoal Lake by Deanna Dodgson in 2008. The Delaware Skipper has a restricted range in central southern Manitoba; one was photographed by Deanna Dodgson near Stuartburn on August 3, 2008. The Dakota Skipper is a Threatened species at both the provincial and national level, with Manitoba populations persisting mainly in the southwestern Interlake. The uncommon Dusted Skipper was formally recorded at a dozen localities in the Red and Assiniboine watersheds, but its current status is uncertain; one online report was near the Shoal Lakes in 2019.