Butterflies and Moths — Order Lepidoptera

Moths

There are about 85 species of moths in the Arctic, a much lower diversity than in southern Canada – Southern Ontario, for example, has over 2000 species. The biology of many arctic moths is poorly understood; even basic details, such as the length of their life cycle and the food plants of their caterpillars are unknown. At least one species, Acsala anomala, is known to feed on lichen, and some moth caterpillars in the genus Olethruetes live underground, feeding on the roots of louseworts (Pedicularis). Many other arctic caterpillars are generalists, feeding on whatever plants are available. As in the south, adults either fail to feed or simply consume nectar. Low temperatures make it impossible for the caterpillars of most species to reach maturity in a single year. Because of this fact, the adults of some species are only observed in a particular region every second or third year. The body temperature of moths must reach a certain level before they can fly, and most arctic moths have adapted to the frigid conditions by evolving dark wing or body colours. These moths must bask in sheltered areas in order to absorb a sufficient amount of heat from the sun. The females of some arctic species never take to the air, but instead remain grounded, emitting chemical attractants to lure a mate. Females lay their eggs and die shortly thereafter.


Butterflies

About 50 species of butterflies occur in the Arctic, but only seven of these survive in the High Arctic Islands. Most arctic caterpillars do not specialize on a single species of plant for food while many southern species are specialists, such as the Monarch butterfly which feeds exclusively on milkweeds. Like moths, the larvae of most arctic butterflies do not mature within a single year – the environmental conditions just do not allow for fast growth rates. The adults of arctic butterflies are active fliers, although most remain close to the ground, out of the wind, seeking warmer air in sheltered spots. On warm, sunny days, when the wind is calm, butterflies are a common sight.


Colias sp., a pierid.
Typically, adults fly in early summer – late June to July – but a few stragglers persist into August. Arctic butterflies, like their moth relatives, gain most of their body heat by basking, exposing their wings to soak up the sun's rays. The warmed blood in their wings is then circulated to the rest of the body via the wing veins. Some species of arctic butterflies rest with their wings folded up, and then tilted to the side, to expose the undersides to the sun’s heat. However, most open their wings to expose their topside. Either way, basking is a necessity for arctic butterflies, because they cannot fly until their body temperature is warmed to at least 10oC. During periods of cool, cloudy weather, butterflies may fail to fly for several weeks.
Lycaena phlaeas, a lycaenid.

Skippers (Family Hesperiidae) are small butterflies with hooked antennae and erratic flight patterns. Species in this family, as well as the swallowtails (Family Papilionidae) are restricted to the Low Arctic. Some of the most common sorts of butterflies in the Arctic are the sulphurs (Family Pieridae) – Colias species with delicate, pale white, green or yellow wings – and the blues and coppers (Family Lycaenidae) – small butterflies with iridescent colouration in shades of blue and orange. Both of these families are represented in the High Arctic. The four common sulphur species in the Arctic belong to the genus Colias. While the colour of their upper wings are shades of pastel, the lower surfaces of their wings are darker and dappled with grey. This colouration aids in heat absorption, since the butterflies bask in the sun with their wings folded straight up above their bodies. The larvae of some arctic sulphurs feed on legumes, while others consume bilberry plants.

Boloria frigga, a nymphaild.

Brush-footed butterflies (Family Nymphalidae) are so named because their front pair of legs is very short, stubby, and covered with hairs. These butterflies, which are often shades of orange and brown, are extremely common around the world, and a few species have colonized the High Arctic. All of the species belong to the genus Boloria, and have similar upper wing patterns, but can be told apart by the silver markings on their lower wing surfaces. The larvae of these butterflies feed on a variety of perennial shrubs including crowberry, Empetrum nigrum, arctic blueberry, Vaccinium uliginosum, mountain avens, Dryas sp., and willow, Salix sp.


Oeneis sp., a satyrid.

Satyridae, the wood nymphs, are not particularly colourful butterflies – with hues of grey, brown, and black – but they are distinctive in flight. Their erratic patterns of bobbing up and down in flight earned the family its name – the satyrs of Greek mythology were the drunken, dancing companions of Dionysus, the god of wine. Although their flight pattern is unpredictable, these butterflies end each journey the same way – by descending rapidly, closing their wings, and disappearing amongst the vegetation. There are over a dozen satyrs in the Arctic, and some inhabit the High Arctic, where their larvae feed on grasses and sedges.