HETEROPTERA

G.G.E. Scudder

BIODIVERSITY AND ZOOGEOGRAPHY

The 610 species of Heteroptera so far recorded from the Montane Cordillera ecozone, represent 88.4% of the true bugs occurring in British Columbia. This makes this ecozone the richest in Western Canada.

Of the true bugs listed from this ecozone, 19 species occur only in the Eastern Continental Ranges and Northern Continental Divide ecoregions in Alberta (Table 1). They have not yet been reported in British Columbia, but there has been little collecting in adjacent areas.

The Montane Cordillera Heteroptera can be assigned to 10 geographical patterns. Table 2 lists species or subspecies assigned to each category.

Cordilleran, Excluding Beringia. Species that in North America are confined to the mountainous Cordilleran areas in the west, and which also are absent from the unglaciated areas of northwestern North America. Two hundred and two species or subspecies are placed in this category.

Cordilleran, Including Beringian. Species that in North America are confined to the mountainous Cordilleran areas in the west, and which also occur in the unglaciated areas of northwestern North America. Eight species are listed in this category.

Nearctic, Excluding Beringia. Species that are widely distributed in North America, but absent from the unglaciated areas of northwestern North America. One hundred and ninety-seven species or subspecies are placed in this category.

Nearctic, Including Beringian. Species with a wide Nearctic distribution, and which also occur in the unglaciated areas of northwestern North America. Fifty-three species or subspecies are placed in this category.

Nearctic-Neotropical. Species widely distributed in North America, and with a range that extends well into the Neotropical region. Eight species are listed in this category.

Western, Excluding Beringia. Species or subspecies that are confined to western North America, usually west of the 100th meridian, and which are absent from the unglaciated areas of northwestern North America. Fifty-nine species or subspecies are included in this category.

Western, Including Beringian. Species or subspecies that are confined to western North America, and which also occur in the unglaciated areas of northwestern North America. Fifteen species or subspecies are placed in this category.

Holarctic. Species widely distributed in both the Palaearctic and Nearctic. Fifty- one species or subspecies are listed in this category.

Cosmopolitan. Species widely distributed in the world, occurring in several zoogeographic realms. Four species are placed in this category.

Introduced. Species not native to North America, having been accidentally or intentionally introduced. Fourteen species are listed in this category.

The 202 Cordilleran, excluding Beringia species, constituting 33.1% of the heteropteran fauna in the ecozone, is the dominant faunistic element. Many species are confined to southern latitudes in the ecozone, with 37 of these listed as potentially rare and endangered.

The Nearctic, excluding Beringia species, is the second largest element with 197 species, constituting 32.3% of the heteropteran fauna. Four of these species are potentially rare and endangered, and confined to southern latitudes.

The 58 species in the Western, excluding Beringia element, constituting 9.5% of the heteropteran fauna, form the third largest element. Six of the species in this element are potentially rare and endangered, and restricted to the southern parts of the ecozone.

The Nearctic, including Beringian, element with 52 species, constituting 8.7% of the fauna, contains mostly widely distributed species, as does the Holarctic element with 51 species. (8.4% of the fauna).

The minor elements in the heteropteran fauna are the Western, including Beringian with 15 species (2.5%), Cordilleran, including Beringian with 8 (1.3%) and Nearctic-Neotropical element also with 8 species (1.3%). Four species, constituting 0.7% of the fauna are cosmopolitan. There are 14 introduced European species, which make up 2.3% of the fauna.

Most of the non-Beringian elements have invaded the ecozone in post-glacial times from southern refugial areas. The Beringian elements could also have had populations, that in addition, dispersed into the area from the northern Beringian refugium.

The Holarctic species, most of which have a wide distribution in the Nearctic, probably had long-standing New World populations, and post-Pleistocene dispersal into the ecozone could have been from both Beringian and southern refugia. Many of the alien species are recent introductions, with at least one intentionally released for biological control.