J.D. Lafontaine and J.T. Troubridge. 1998. Moths and Butterflies (Lepidoptera) in Smith, I.M., and G.G.E. Scudder, eds. Assessment of species diversity in the Montane Cordillera Ecozone. Burlington: Ecological Monitoring and Assessment Network, 1998.

MOTHS AND BUTTERFLIES
(LEPIDOPTERA)

J.D. Lafontaine
and
J.T. Troubridge

DISTRIBUTION PATTERNS

This analysis of distribution patterns of Lepidoptera of the Montane Cordillera Ecozone relies heavily on the distributional data from butterflies but other examples are included from the moths. For reference, a check list of the macro-moths and butterflies known from the Montane Cordillera Ecozone is included in appendices 1 and 2.

There are three main terrestrial habitat types within the Ecozone: 1) arid bunchgrass habitat characteristic of the Great Basin; 2) montane forests; and 3) alpine tundra habitat above treeline. We examine each of these habitat types, and give examples of distribution patterns associated with them.

Great Basin:  

Montane Forests:      

Alpine Tundra:      

Arid bunchgrass habitat characteristic of the Great Basin occurs in the Ecozone primarily in five disjunct areas. The richest areas in terms of habitat and species diversity, is the Okanagan Valley, and to a lesser extent along the Similkameen River (especially near Keremeos) [slide 5]. More disjunct, and therefore more depauperate habitats are along the Fraser and Thompson Rivers (mainly from Kamloops to Lillooet) [slide 6], farther north along the Fraser River (especially near Williams Lake) [slide 7], and in extreme southeastern British Columbia and Waterton Lakes National Park in adjacent Alberta. Table 2 lists 16 species of butterflies most closely associated with Great Basin habitats and in which of these five areas they occur.

TABLE 2: Distribution of aridland butterflies

Species	Okanagan Valley	Similkameen Valley	Thompson/ Fraser Rivers	Williams Lake	SE BC and SW Alberta
Hesperia juba Juba Skipper	X	X	X	X	X
Hesperia colorado Western Branded Skipper	X	X	X	X	X
Polites sabuleti Sandhill Skipper	X
Polites sonora Sonoran Skipper		X
Pontia beckerii Becker’s White	X	X	X	X	X
Euchloe lotta Desert Marble	X	X	X		X
Lycaena heteronea Blue Copper	X	X	X	X	X
Lycaena nivalis Lilac-bordered Copper	X	X
Satyrium behrii Behr’s Hairstreak	X
Satyrium fuliginorum Behr’s Hairstreak	X	X			X
Satyrium californicum California Hairstreak	X		X
Callophrys affinis West. Green Hairstreak	X
Euphilotes battoides Square-spotted Blue	X	X		X	X
Apodemia mormo Mormon Metalmark	X (extirpated)	X
Phyciodes pallidus Pale Crescent	X	X	X	X	X
Cercyonis sthenele Great Basin Wood- Nymph	X	X	X	X	X
Total 16	15	12	8	7	9

The diversity is greatest in the Okanagan Valley, drops off slightly in the nearby Similkameen Valley, and more abruptly moving farther north to the more disjunct areas near Kamloops and Willams Lake. The arid slopes east of the Kootnay River in southeastern BC and Waterton National Park in southeastern Alberta, are near the American border but are not as closely associated with Great Basin habitat farther south as are the Okanagan and Similkameen Valleys. No similar comparison is possible with the moth fauna because only the Okanagan Valley and the Kamloops area have been adequately collected and there is a great need for selective studies even there. Rich Okanagan habitats like the Purshia tridentata slopes east of Vaseaux Lake in the Bighorn Sheep preserve, the diverse habitats on Anarchist Mountain east of Osoyoos, and the extensive sagebrush areas at White Lake west of Penticton, have barely been studied for moths. Because of the loss of natural habitat in most of the Okanagan Valley, it is critical to determine the true nature of the diverse Lepidoptera fauna that survives there, which areas are critical, and which other arid habitats in British Columbia that they occur, in order to assess topics like threatened and endangered moths and habitats in British Columbia. Some species are widely distributed in both the Great Basin and Great Plains areas and occur throughout southern BC and Alberta wherever suitable habitat occurs. Some examples of this are Acmon Blue (Icaricia acmon), Boisduval’s Blue (Icaricia icarioides), Arrowhead Blue (Glaucopsyche piasus), and Melissa Blue (Lycaeides melissa).

Montane forests are probably the most dominant habitat in the Montane Cordillera Ecozone. These tend to be dominated by Douglas-fir but support and impressive array of other conifer species, as well as areas of deciduous forests, especially poplars and cottonwoods. Montane forest distributions fall into two categories, with exceptions for host specific species limited to specific areas. The two range types are Boreomontane species and Montane Cordillera species. Typical ranges for Boreomontane species include both the boreal forest zone across most of central Canada and the comparable habitat in the western mountains. Most of these species occur in relatively mesic habitats like spruce forests. Some range as far south in BC as south- central BC (such as north and east of Kamloops), south to the higher areas of Manning Park and extreme north of Washington State, and some extend down the Rocky Mountain system to northern New Mexico and the White Mountains of eastern Arizona. Montane Cordillera species typically occur through most of the montane areas of western United States, oftem in more xeric habitats such as pine forests, and occur northward in BC to central BC and occasionally to southern Yukon. In some instances closely related species occupy these two general ranges and occasional hybrids may occur where their ranges come together near Kamloops. Examples of Boreal/Montane species pairs are the White Admiral (Limenitis arthemis) and Lorquin’s Admiral (Limenitis lorquini), and the Canadian and Western Tiger Swallowtails (Papilio canadensis and Papilio rutulus). A more restricted type of montane distribution are species with ranges that extend northward in the Cascades Range from northern California into the southwestern part of the Ecozone in the Manning Park area (the Okanagan Range Ecoregion). The Indra Swallowtail (Papilio indra) and Hoffmann’s Checkerspot (Chlosyne hoffmanni), are examples of this pattern.

Arctic and alpine tundra habitat occurs above treeline throughout the Ecozone. This includes associations with mesic alpine habitat in most of the Ecozone that is characterized by species that occur in the mountains of western United States and Canada, and dry tundra habitat, mainly in the Rocky Mountain rain shadow in Alberta, where the ranges of many arctic species extend southward into the Ecozone. Some species more commonly associated with arctic habitat extend into the northern portion of the Ecozone, and include Eversmann’s Parnassian (Parnassius eversmanni), Palaeno Sulphur (Colias palaeno), and Polaris Fritillary (Boloria polaris), while others like the Dingy Fritillary (Boloria improba) and the Polixenes Arctic (Oeneis polixenes) extend down the drier east slopes of the Rocky Mountains to southern Alberta. Many other species are less specific and occur in alpine habitats throughout the ecozone; these include moths such as Merolonche lupini, Lasionycta poca, and Lasionycta luteola.