Butterfly

Butterfly, term referring to insects of order Lepidoptera [Gk "scaly wings"]. The Canadian fauna includes 272 known species, compared to 695 known from North America as a whole, and over 20 000 worldwide.

Monarch Butterfly Chrysalis
The mature monarch larva hangs inverted from a suitable plant in the form of a lovely green chrysalis (the pupa) (photo by Bill Ivy).
Painted Lady
Common in most of Canada except the northern Yukon, NWT and Québec (Corel Professional Photos).
Atlantis Fritillaris
Common in most of southern Canada and in the southwest NWT (Corel Professional Photos).
Monarch Butterfly, Adult
An adult monarch butterfly emerges from the pupal skin. It takes 10 to 20 minutes for the wings to spread, dry and stiffen (photo by Bill Ivy).
Monarch Butterfly Caterpillar
The unmistakable monarch caterpillar with its brilliant green colour and black and yellow stripes (photo by Bill Ivy).
Sulphur Butterfly
The common sulphur (C. philodice) is found across southern Canada, except Newfoundland (Corel Professional Photos).
White Admirals
White admirals are found from western Manitoba to Alaska (Corel Professional Photos).
Butterfly and Moth
Among the differences, butterfly have antennae that end in a knob, moths have antennae of many shapes. Butterflies rest with wings upright and moths with wings laid out flat. Moths are active at night, butterflies by day (artwork by Jan Sovak, 1989).

Butterfly, term referring to insects of order Lepidoptera [Gk "scaly wings"]. The Canadian fauna includes 272 known species, compared to 695 known from North America as a whole, and over 20 000 worldwide. Possibly about 60 species remain to be discovered or recorded in Canada.

Structure

Butterflies are characterized by having antennae that are knobbed or hooked at the tips. They fly by day and are usually brightly coloured. Species found in Canada are varied in size, wingspans ranging from under 2.5 cm to 7.5 cm. Adults have a long, hollow tongue (proboscis) and usually feed on nectar. Larvae of all butterflies in Canada feed on vegetation.

Reproduction and Development

The life cycle of a given species may require from a few weeks to 2 years to complete, and involves a complete metamorphosis through egg, larva (caterpillar) and pupa (chrysalis) to adult. Different families have characteristically shaped and marked eggs, which are usually laid on a host plant, singly or in batches of up to 300. Species differ in ways of overwintering: most pass the winter in the egg, larval or pupal stage, but a few (eg, mourning cloak and Milbert's tortoiseshell) overwinter as adults.

Range

Butterflies inhabit all areas of Canada where flowering plants occur. Their numbers diminish northwards, down to about 16 species in the Arctic. Although some species (eg, red admiral and common sulphur) are widely distributed, others are confined to particular habitats or geographical regions. Monarch and painted lady butterflies migrate to Canada from the US.

Butterfly populations are controlled by inclement weather, diseases, parasites, predators and habitat suitability. Cool, sunless summers and mild, damp winters are particularly detrimental. Birds consume many caterpillars and adults, while dragonflies and spiders also take their toll. Diseases can be particularly rife when population densities are high, but the many parasitic flies and wasps that regularly prey on caterpillars probably exert the greatest natural control.

Larvae of some species of blues and hairstreaks are tended by ants for the honeydew they secrete, and probably receive some protection from other insects. Natural controls are necessary and probably do not threaten the existence of butterflies. However, destruction of natural habitats, large-scale spraying to control insect pests and, possibly, acid rain are man-made hazards that could have far-reaching detrimental effects on Canada's butterfly fauna.

Interaction with Humans

Although butterflies are generally harmless to human interests, a few are pests. Larvae of cabbage white butterflies are a widely distributed pest of plants of the cabbage family, while another accidentally introduced butterfly, the European skipper, has become a pest of hayfields. Occasionally, others may become a local nuisance when unusually high population levels develop.

Butterflies are useful in plant pollination, in providing food for other creatures, and as indicators of environmental stability. They are a source of scientific and recreational interest, bringing charm and beauty to wherever they live. See also monarch butterfly.