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.
The terms "butterfly" and "moth" are often thought of as the two natural groups that make up the order Lepidoptera but in reality the butterflies are only one of many Lepidoptera lineages; butterflies are more closely related to the larger moths than either group is to the more primitive families of moths. The butterflies and the larger moths are often associated in a group called the "macrolepidoptera." The families of smaller moths are referred to as "microlepidoptera." While the macrolepidoptera probably represents a natural group, the microlepidoptera is more a grouping of convenience that lumps together many different families of small-sized, primitive moths. For convenience of discussion, we have arranged the 67 families of Lepidoptera into three groupings that represent different habits and different levels of knowledge.
The first group is the microlepidoptera (GROUP I), which includes 49 families of mostly small-sized moths with larvae that are concealed feeders. The microlepidoptera families can be arranged in four subgroups on the basis of larval habits. The first of these subgroups is 12 families (best illustrated by the large family Gracillariidae) that are the leaf miners. The larvae are called leaf miners because the they feed on the chlorophyll between the upper and lower leaf surfaces; this results in a characteristic clear patch in the leaf where the green chlorophyll has been removed. Many species can be identified in the larval stage by considering both the shape and position of the mine on the host plant and the identity of the host. The adults have narrow wings like those of a mosquito (wing expanses of 5-10 mm are typical), usually with a wide hairlike fringe. The leaf mining microlepidoptera are generally rarely collected and poorly known, especially in western North America. The second subgroup of microlepidoptera are the case-bearers. Four families (Adelidae, Incurvariidae, Tineidae and Coleophoridae) are small, narrow-winged moths, like the leaf-miners, but the larvae conceal themselves in a case made from of silk and debris; the larvae are often miners when small and build a case when they get larger. A fifth family of case-bearers, the Psychidae, or bagworms, are larger; the moths are broader winged, usually 10-12 mm in our species but up to 40 mm in the southern US; the females of most species are wingless and remain in the case to mate, lay their eggs and die. The third subgroup of families is the borers, in which the larvae may bore in the stems of plants, or in the flower heads and fruit. These are varied in size and appearance; the ghost moths (family Hepialidae) are large moths with 25 to 100 mm wingspans; the clear-winged moths (family Sesiidae) are wasp mimics; most other families (e.g. Carposinidae, Momphidae) are small, drably coloured moths similar to leaf-miners. The fourth and largest subgroup of the microlepidoptera are leaf-rollers. Most members of the large families Tortricidae, Gelechiidae, and Pyralidae fall into this category. The adults are generally larger than leaf-miners (wing expanses of 15-30 mm are typical) and the wings are more triangular in shape with only a narrow fringe. The larvae most commonly roll or fold a leaf and tie it with silk, or tie several leaves together, and feed in the protected enclosure. This group includes agricultural pests (e.g. European Corn Borer, Ostrinia nubilalis; Oblique-banded Leafroller, Choristoneura rosaceana; Codling Moth, Cydia pomonella), forest pests (e.g. Western Spruce Budworm, Choristoneura occidentalis), and household pests (e.g. Indian-Meal Moth, Plodia interpunctella). A total of 737 species of microlepidoptera are known from the Montane Cordillera Ecozone. The actual number of species in the Ecozone is probably at least double this number because of our poor knowledge of the leaf mining microlepidoptera. A significant portion of the recorded microlepidoptera are known from only one or two localities in the area so little can be said of range limits or distribution patterns.
The second major division of the Lepidoptera is the macrolepidoptera which contains the larger moths and the butterflies. For discussion purposes, we treat the macrolepidoptera in two groups, the macromoths (GROUP II) and the butterflies (GROUP III). The 12 families of macromoths contain 1073 species in the Montane Cordilleran Ecozone, this comprising 93% of the entire known macromoth fauna from British Columbia (see Table 1) Two families, the inch- worms (Geometridae) and cutworms (Noctuidae) make up 90% of the Group III fauna. The cutworms alone, with 665 known species in the Ecozone, make up 33% of the entire Lepidoptera fauna. The larvae usually are exposed when feeding but are usually protected by spines (Saturniidae), tufts of hair (Arctiidae, Lymantriidae, Lasiocampidae, some Noctuidae), or cryptic coloration (Geometridae, Drepanidae, Notodontidae, most Noctuidae).
Many noctuid larvae hide during the day in the soil and leaf litter and come out at night to feed. This group includes our largest Lepidoptera with the Ceanothus Silk Moth (Hyalophora euryalis) having a wingspan up to 13 cm. Typical wingspans of most macrolepidoptera are between 25 and 40 mm although some species may be as small as 12 mm (e.g. Noctuidae: Hypenodes). This group contains some very familiar pests such as Tent Caterpillars (Lasiocampidae: Malacosoma), Tomato Hornworm (Sphingidae: Manduca quinquemaculata), introduced into the Ecozone from farther south, Gypsy Moth (Lymantriidae: Lymantria dispar), Armyworm (Noctuidae: Pseudaletia unipuncta) Speckled Green Fruitworm (Noctuidae: Orthosia hibisci), and Corn Earworm (Noctuidae: Helicoverpa zea). Unfortunately, only a few groups of macrolepidoptera are popular with amateur collectors so distributional information on most families remains rather spotty. Popular groups are the Sphinx (Hawk Moth) family (Sphingidae), the Giant Silk Moths (Saturniidae), Tiger Moths (Arctiidae), and a group of cutworm moths called Underwing Moths (Noctuidae: genus Catocala).
The third group (GROUP III), a subset of the macrolepidoptera, is the butterflies. Six families of butterflies occur in the Montane Cordillera Ecozone and 173 species. The combination of colorful patterns, diurnal flight, and abundance of identification aids, has made butterflies the most popular insect group with amateur entomologists. As a result, the distribution of the butterflies in Canada in general and the Montane Cordillera Ecozone in particular is well known so it is these patterns that form the primary basis for the analysis of distribution patterns given below. As in the macrolepidoptera, most butterfly larvae feed exposed and rely on cryptic coloration, warning coloration, or spines for protection. The majority of butterfly larvae are covered with a dense layer of short hair that gives them a fuzzy appearance (e.g. Lycaenidae, Hesperiidae , Pieridae, and some Nymphalidae) or are armed with impressive branching spines (e.g. most Nymphalidae). Others, such as the Monarch (Danaus plexippus) and some of the Swallowtails (Papilionidae) are toxic to predators and have a warning coloration. Many butterflies are powerful fliers and some are strongly migratory; however, only five butterfly species occur in the Ecozone as seasonal migrants.