Moths and butterflies together form the Order Lepidoptera (the “scale-winged” insects). Lepidoptera are one of the five largest insect orders, with an estimated 300,000 to 400,000 species worldwide (about 160,000 have been discovered and named so far). There are 93 species of butterflies confirmed present in the NWT, three additional species are vagrant and have been observed irregularly, sometimes only once, and one more species is expected to be present, and there are 582 species of moths confirmed present in the NWT, and two more species are expected to be present.

Butterflies

The NWT is rich in butterflies. The list below includes all butterfly species currently known to be present in the NWT. There are likely more species awaiting discovery either as entirely new species or as new territorial records for species with ranges that just touch the borders of neighbouring provinces and territories.

Butterflies are the most widely recognized and charismatic group of insects. Most insects evoke feelings of fear, disgust or ambivalence, but the butterflies are universally revered for their beauty and docile nature. They are synonymous with flowers and warm, sunny days. Few animals, plants, jewels, or human creations can match the magnificent array of colours and patterns they possess. Their beauty and diversity have attracted the attentions of people on a scale far beyond that of most other plants or animals.

Butterfly eggs are laid on or near a preferred host plant. Upon hatching, the young caterpillars immediately begin feeding on the leaves and flowers. After shedding their exoskeletons five times and reaching maximum size, the caterpillars seek a safe place to pupate (form a chrysalis) and transform until they are ready to emerge as the winged adult. The adults lack the chewing mouthparts of the voracious caterpillar. Instead, adults possess a long “tongue” suitable for drinking nectar from all but the deepest flowers. They also use this tongue to imbibe fluids from less appetizing sources such as mud, rotting fruit, dung and even carcasses. In fact, these sources are often the best places to find mixed flocks of butterflies and lepidopterists employ mixtures of rotting fruit, beer. and urine as attractants.

Habitat destruction and degradation are the usual causes of butterfly declines and losses in the world. Direct modification of habitats by humans is unlikely to have a major influence on NWT species; however, the indirect effects of our activities like pollution and climate change may be significant. Butterflies are one of the best groups of animals to use as indicators of change because they are relatively easy to identify, their life histories and distributions are well known, they often feed on specific plants, can multiply quickly, and are highly mobile as adults.

Moths

Moths make up about 95% of the Lepidoptera globally. All species of moths recorded from the NWT are included in the NWT General Status Ranks. Unlike butterflies, relatively few moths can be easily identified in the field or from a photograph. Instead, most require a concerted effort to collect, then careful preparation and identification by a skilled taxonomist.

Often vilified and commonly characterized as the drab and uninteresting cousins of butterflies, the moths are anything but. What moths lack in bright and vibrant colours is easily made up for by the incredible variety of textures, shapes, patterns, subtle earth tones and hairs they employ to blend into their surroundings.

Adult moths rely on a variety of strategies to survive in the various regions of the NWT. A few species, especially those further north in the Arctic, are diurnal so they are either brightly coloured to advertise toxins sequestered within them or cryptically coloured so they can camouflage themselves amongst the low growing vegetation or rocky terrain. Other species flash eye spots or bright hind wings when disturbed to startle or confuse potential predators long enough to escape.

Those in the High Arctic are reliant on the sun to stay warm, thus are darkly scaled and covered in pubescence (hair), especially near their thoraxes and abdomens, to absorb the precious solar heat so they can manoeuvre to feed and find mates. For those species in the southern NWT that are nocturnal, the effectiveness of colours as a warning or for attracting mates is not important.

For these night fliers attracting mates is accomplished using pheromones and for this they have very sensitive chemical sensors on their antennae to locate mates in the dark and at great distances. Flying at night also requires adaptations to function in cool temperatures. Effective camouflage allows moths to rest safely in exposed positions like tree trunks to absorb heat during the day and the abundant hairs on the body create an insulating layer to hold this warmth into the night.

Like butterflies, moths lay eggs on or near suitable host plants upon which the young caterpillars will feed and grow. Birds and many species of insects seek out caterpillars to eat or to act as hosts for their young. Caterpillars employ camouflage, toxic and distasteful chemicals, hairs, bristles, eye spots, and various behaviours to avoid this vast array of enemies.

After a series of moults the larva enters the pupal stage, often wrapping itself within a silk cocoon. Although often thought of as dormant because it doesn’t eat or move, the pupa is very actively rearranging its tissues into a magnificent, winged marvel. Once free of the pupal skin the adult moth must pump up its folded wings before they harden. If all goes well the moth will go off in search of mates and host plants on which to start the process again.

In Arctic regions of the NWT with short growing seasons, the development of a moth from egg to adult often requires several years. For instance, the Arctic moth (Gynaephora groenlandica) can take up to 10 or more years in the High Arctic to develop from egg to adult.

The additional challenge of short nights in the North means that many species that are nocturnal elsewhere, have to adapt to being active in the daytime here.

Currently our knowledge of the NWT moths has focused on larger species (also referred to as ‘macromoths’) but our knowledge of the elusive micro-moths is growing.

Many species are at their northern limit in the southern NWT. Some northern species have specialized habitat or host plant requirements and could be at risk from climate change. Only with more studies on both moths and their host plants can we better rank their biological status in the NWT.

Moths are less showy and more difficult to identify than butterflies but they are nonetheless worthy of our attention. Once located, either by careful observation or at lights, moths are usually easy to approach and make excellent subjects for macro photography. They are also good candidates for teaching insect development and metamorphosis. Caterpillars can be reared on the plant species they are found on and with time will pupate and emerge as adult moths.