People passionate about nature

A Snapshot of Butterflies in Southeast Manitoba - Part 4

A citizen science project to record butterfly species and numbers

by Peter Taylor

Part 4: Fritillaries (Speyeria, Boloria, Euptoieta)

Atlantis Fritillary (1347 reported)
Northwestern Fritillary (2 reported)
Great Spangled Fritillary (634 reported)
Aphrodite Fritillary (500 reported)
Meadow Fritillary (443 reported)
Silver-bordered Fritillary (242 reported)
Arctic [Purple] Fritillary (245 reported)
Frigga Fritillary (2 reported)
Freija Fritillary (13 reported)
Bog Fritillary (1 reported)
Variegated Fritillary (28 reported)

The eleven fritillary species found in our area form a distinctive group within the family Nymphalidae, the brush-footed butterflies. This is the most diverse butterfly family, with over 6,000 species worldwide. One of the main family characteristics is the reduced size of the front pair of legs, which often have brush-like hairs and are curled up in front of the eyes with a sensory rather than walking function. Thus, these butterflies are in effect quadrupeds, though anatomically hexapods like all insects.

Above: The “brush-footed” forelegs are prominent in front of the eyes of this Arctic Fritillary. Photo near Milner Ridge on July 25, 2015 by Peter Taylor.

Our fritillaries are grouped mainly as greater (genus Speyeria) and lesser (Boloria), while one member of the Neotropical genus Euptoieta, the Variegated Fritillary, is an uncommon migrant that may turn up any time from late spring to early fall.

Above: Two Variegated Fritillaries jostle for nectar from White Sweet-Clover flowers on a windy day at Brightstone on September 10, 2016 by Peter Taylor.

Greater and lesser fritillaries have wingspans mostly in the ranges 50-70 mm and 32-44 mm, respectively, making the groups fairly easy to distinguish in the field. All have intricate dorsal (upper surface) patterns of dark, checkered and linear markings and rounded spots on an orange background.

Above: Mating pair of Atlantis Fritillaries (male on left), If disturbed, a male butterfly carries the female in a short flight for cover. Photo south of Bloodvein on July 6, 2016 by Peter Taylor.

The ventral (under surface) patterns are quite distinctive for the lesser fritillaries, though not always easy to see in the field, and more challenging to separate for the greater fritillaries.

Above: Sometimes the butterflies themselves get confused! Here, a male Atlantis Fritillary (right) appears to be courting a Great Spangled Fritillary, whose raised abdomen is an expression of disinterest. Note the different eye colours. Photo near Pinawa on July 17, 2018 by Peter Taylor.

The underwings of greater fritillaries and several of the lesser species have numerous, attractive silvery-white spots. Digital photography is a great aid to field identification, revealing for example the bluish-grey eyes of Atlantis Fritillaries (orange or brownish in most other species). All of Manitoba’s greater fritillary caterpillars feed on various species of violets, as do Meadow and Silver-bordered Fritillary larvae, while other species have more diverse tastes.

The three common greater fritillaries have a single summer flight, peaking in July, with Aphrodite Fritillary averaging slightly later than Great Spangled and Atlantis.

Above: This finely marked male Aphrodite Fritillary is easier to identify than boldly marked females, which may closely resemble Atlantis Fritillaries. Photo near Inwood on July 24, 2018 by Peter Taylor.

Though they are quite common annually, 2018 was a bumper year for all three species. These widespread butterflies are often found in close proximity when visiting thistles, milkweed, or other abundant nectar sources, usually in or near forest settings. Aphrodite Fritillaries, however, tend to favour dry (rocky or sandy) upland, while Atlantis Fritillaries favour lower-lying, boggy habitats. The Northwestern Fritillary, only recorded twice in our five-year survey, reaches its eastern range limit in SE Manitoba. Three prairie species, the Regal, Callippe, and Edwards’ fritillaries, formerly occurred at least sparingly in our area but have not to our knowledge been recorded here for many years.

The two most widespread lesser fritillaries, Meadow and Silver-bordered, also tend to favour relatively dry and wet settings, respectively.

Above: Silver-bordered Fritillaries rarely pause for long in the open like this one. Photo near Milner Ridge on August 12, 2017 by Peter Taylor.

Above: This Meadow Fritillary, probing a dirt-road surface for moisture and salt, is identifiable by its indistinct hindwing pattern and slightly angular forewing shape. Photo near Prawda on July 9, 2016 by Peter Taylor.

Both of these two species have two generations per year, with well-defined peaks in late May to early June and in July for Meadow, but with more drawn-out flight periods for Silver-bordered. All the other lesser fritillaries have one generation per year. Of these, the fairly widespread Arctic Fritillary has a late July peak and can be found in a range of both dry and wet coniferous forest settings. Formerly known as the Purple Lesser Fritillary, this distinctive southern population has only recently been classified as a subspecies of the Arctic Fritillary. The three remaining species are boreal wetland specialists that are rare and inaccessible within our area; Frigga and Freija fritillaries peak in late May, while the Bog Fritillary should be sought in mid to late June.