Montana Field Guide

[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 4.6-5.5 cm. Single-tailed. Uppersurface pale to bright yellow with medium to broad black border and tiger stripes; hindwing with uppermost marginal spot yellow or absent (never orange), other marginal crescents yellow, red-orange crescents at inner angle near tail. Undersurface of forewing with more-or-less continuous yellow marginal band, hindwing marginal spots narrow, submarginal metallic blue zones expanded, postmedian area without orange infusion.

One flight, June to July (Ferris and Brown 1981; Scott 1986). Mainly June to July , but March to October in Pacific lowlands (Glassberg 2001). Late May to late August in Colorado (Emmel 1964; Scott and Scott 1978; Scott and Epstein 1987), mid-April to late September in Oregon and Washington (Pyle 2002), mid-April to mid-August in Oregon (Warren 2005), late May to August in British Columbia (Guppy and Shepard 2001).

Best determined by a combination of yellow base color, hindwing with single tail, uppersurface of hindwing with uppermost marginal spot yellow or absent (never orange), undersurface of forewing with more-or-less continuous yellow marginal band.

Non-migratory.

Riparian woodlands, wet montane meadows, wooded suburbs, parks and gardens, canyon streams (Emmel 1964; Ferris and Brown 1981; Opler and Wright 1999; Glassberg 2001; Guppy and Shepard 2001; Pyle 2002). In Glacier National Park, Montana reported from mesic montane meadows and above treeline in alpine terrain (Debinski 1993); in the Greater Yellowstone Ecosystem reported from many habitats near moisture and tundra-edge deciduous woods (Debinski and Pritchard 2002).

Larval food plants are native and exotic trees and shrubs, including members of the Rosaceae (Malus, Prunus (several species), Rubus), Salicaceae (Populus (several species), Salix (several species)), Betulaceae (Alnus (several species), Betula), Aceraceae (Acer), Ulmaceae (Ulmus), Platanaceae (Platanus), Lauraceae (Persea), Oleaceae (Fraxinus, Ligustrum, Syringa), Rutaceae (Ptelea), and Fagaceae (Quercus) (Emmel et al. 1970; Scott 1986, 1992, 2006; Guppy and Shepard 2001; Graves and Shapiro 2003; Warren 2005). Adults feed on flower nectar (including Achillea, Agastache, Apocynum, Aquilegia, Asclepias, Balsamorhiza, Campanula, Carduus, Ceanothus, Chaenomeles, Cirsium, Coreopsis, Delphinium, Dianthus, Dipsacus, Echinacea, Eriodictyon, Eriogonum, Helianthella, Helianthus, Hesperis, Jamesia, Leontodon, Liatris, Lilium, Medicago, Nepeta, Oxytropis, Paeonia, Philadelphis, Phlox, Potentilla, Prunus, Purshia, Rhododendron, Rubus, Rudbeckia, Syringa, Tilia, Verbena), carrion, and mud (Scott 1986, 2014; Pyle 2002).

Females lay eggs singly on upper surface of host plant leaf (Scott 1986, 1992, 2006; Guppy and Shepard 2001; James and Nunnallee 2011). Eggs per ovariole (1/8 total number) about 70 (Ehrlich and Ehrlich 1978). Eggs hatch in about 6-10 days, develop from L1 instar to L4 or L5 instar and pupae in about about 43-56 days, depending on temperature and food supply quality. Larvae solitary, feed on host plant leaves, spin thin silken pad on leaf surface on which to rest when not feeding (the silk mat draws the leaf into a gentle concave shape), wander as mature larvae prior to pupation, pupate on ground in litter, overwinter (diapause) as pupae, adults eclose (emerge from pupa) early the following spring (Scott 1979, 1986; Guppy and Shepard 2001; James and Nunnallee 2011). Males patrol or perch throughout the day on hilltops, along streams, woodland edges, other barriers, in search of females (Scott 1975b, 1986; Guppy and Shepard 2001; Pyle 2002; James and Nunnallee 2011).