|Composition of the Fauna|
|The insects of Canada represent a North American and holarctic fauna impoverished by northern conditions. Some characteristic southern elements
appear in the fauna, which also has arctic endemics and a few distinctive Cordilleran forms such as grylloblattids. |
Nearly 34,000 species of terrestrial arthropods have been reported in Canada, and it is estimated that there are another 33,000 species that have not yet been described. Insects make up the largest class of terrestrial arthropods at nearly 30,000 known species. More than 2,000 species of terrestrial arthropods, three-quarters of them insects, have been reported from the Arctic. Several hundred species occur in the high Arctic.
The northern aspect of the Canadian fauna as a whole is shown by a predominance of advanced endopterygotes. Within these groups, Diptera are relatively well represented, and Coleoptera less well represented, a trend that is especially apparent in more northern parts of the country. Similar good representation of certain northern groups occurs at family, genus, and species levels.
Even in northern regions where the fauna is less diverse, some species are remarkably abundant. For example, biting flies (black flies, mosquitoes, midges, horse flies) are especially numerous in the boreal zone.