A Northern Pearly-Eye Butterfly In Algonquin Provincial Park, Ontario

This past summer, Bob and I undertook to hike the Mizzy Lake Trail in Algonquin Provincial Park in Ontario. For a summer’s day, the temperature was not all that hot, but we were blessed with wonderful sunshine and a gentle breeze to cool us over the course of the 7 hours that it took to complete our hike. Along about mid-morning, amidst the flickering shadows cast by millions of green leaves, a Northern Pearly-Eye Butterfly (Lethe anthedon) settled its dainty body on some foliage at the edge of the thick forest.

The Mizzy Lake Trail takes in areas of varied habitat including nine small lakes and ponds, a section that follows an abandoned railway bed, dense deciduous forest, a treeless meadow, and stands of Black Spruce and Tamarack. It was delightful experiencing such a diverse set of conditions all within the trail’s 11-kilometre stretch.

Northern Pearly-Eye Butterflies, unlike most other species of butterflies, are highly adapted to forest dwelling. In fact, these shade-loving butterflies are seldom seen in open areas unless it happens to be a cloudy day, so we were indeed very lucky to have caught sight of this lovely specimen. Rich deciduous or mixed wooded areas make perfect habitat for the Northern Pearly-Eye provided there is a nearby source of water.

We did not realize until later that it is quite common to see a Northern Pearly-Eye perched, head down, to one side of a sunlit tree just as we found this particular one. Another place to look would be the bottom 3 metres (9.8 ft.) of a tree trunk where a Northern Pearly-Eye Butterfly is apt to roost and feed on sap from tree wounds. The types of trees favoured by Northern Pearly-Eye Butterflies are willows, poplars and birch. These butterflies never feed on nectar from flowers but will take nourishment from dung and even mud.

Bob noted that, prior to alighting on a large leaf, the Northern Pearly-Eye butterfly flew swiftly and erratically making it a challenge to keep the little creature in his sights. Once pinpointed, we were able to observe the butterfly for quite some time even though it occasionally lifted off and moved to a different leaf. They do like to bask in warm sunny patches and will even do so into the evening hours, but there it was at mid-morning reveling in the bright sunshine.

Northern Pearly-Eye Butterflies are medium-sized butterflies with a wingspan of anywhere between 43-67 mm (1.7-2.6 in.). The soft purplish brown colour appears on both the top side (dorsal surface) and bottom (ventral surface) of the wings, and the wings have lightly scalloped edges. I think the dark eyespots on the wings make these butterflies very striking. There are four black spots aligned on the forewings, repeated both on the dorsal and ventral surfaces, but there is a slight difference in that those on the underside have white pupils. The hindwings have five spots above and six below, with the sixth on the underside having a double pupil.

Northern Pearly-Eye Butterflies belong to the family of butterflies known as Nymphalidae, more commonly known as Brushfoots or Brush-footed butterflies. Over 6,000 species of butterflies belong to this family including Monarch, Red Admiral and Painted lady Butterflies. The Brushfoots are so named because their first pair of legs are quite short and resemble little brushes.

If you take a close look at the Northern Pearly-Eye Butterfly, it is possible to discern the orange tips on the end of the black antennal clubs. This detail is diagnostic when trying to differentiate the species from the Pearl Crescent that has black and white antennal clubs or the Southern Pearly-Eye with orange antennal clubs. Bob and I learned that it is usually the males that perch on vegetation at the edges of clearings as they wait for females to come by, but they are just as apt to patrol an area in search of a mate. The time was right for Bob and I to see this butterfly because they only fly from mid-June to early August. One brood is produced per year in Canada, and the third and fourth instar larvae or caterpillars will hibernate over the winter. For now, the butterfly enjoyed the soft breeze and warm sunshine as did Bob and I before we moved once again under the dense forest canopy.

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