Montana Field Guide

[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 2.6-3.3 cm. Uppersurface black, forewing with white apical spots and red-orange median band, hindwing with red-orange marginal band; undersurface mottled blackish-brown, forewing costal margin with red, blue, and white patches mostly surrounded in black.

Two flights over much of range, late-June to early August and late August overwintering to May; several flights nearly all year in southern Texas, southern Florida, and lowland California (Scott 1986). March to November in southern California to Texas, mainly May to October northward(Glassberg 2001). Late March to late October with peaks in July and September in Oregon and Washington (Pyle 2002); February to November in Oregon (Warren 2005); mid-April to June and late July to October in British Columbia (Guppy and Shepard 2001).

Best determined by the uppersurface black base color with transverse red-orange median band across the forewing (the band also present on forewing undersurface) and the broad uppersurface hindwing marginal band of the same color.

Migratory; several mass northward movements documented in US and Canada, migration southward less evident to unlikely. Adults in Oregon, Washington, and British Columbia probably do not survive the winter, requiring immigration to sustain presence in those regions (Scott 1986; Guppy and Shepard 2001; Pyle 2002).

Openings near stream courses, marshes, seeps, moist fields and meadows, city parks, gardens, hilltops (Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002). In Glacier National Park, Montana reported from riparian areas (Debinski 1993).

Larval food plants most often are species of Urtica but also include Boehmeria, Humulus, Laportea, Parietaria, Pilea, Pipturus, and Soleirolia (Scott 1986, 1992, 2006; Pyle 2002; James and Nunnallee 2011). Adults feed on flower nectar (including Ageratum, Apocynum, Arnica, Asclepias, Beteroa, Bidens, Blephilia, Buddleia, Camassia, Ceanothus, Centaurea, Cersis, Chrysothamnus, Cirsium, Claytonia, Clematis, Cornus, Coronilla, Dicentra, Echinacea, Erigeron, Erioganum, Geranium, Gutierrezia, Helianthus, Hydrophyllum, Jamesia, Lithospermum, Machaeranthera, Medicago, Mertensia, Monarda, Nepta, Phacelia, Physocarpus, Polygonum, Prunus, Pycanthemum, Ratibida, Rhus, Ribes, Rorippa, Rosa, Rudbeckia, Salix, Senecio, Silphium, Solidago, Stachys, Symphoricarpos, Symphyotrichum, Syringa, Thalspi, Tilia, Trifolium, Vicia), tree sap, aphid honeydew, rotting fruit, carrion, and dung (Scott 1986, 2014; Pyle 2002; Tooker et al. 2002; James and Nunnallee 2011).

Females lay eggs singly on the uppersurface of host plant leaves. Eggs hatch in about 7 days (depending on temperature), develop rapidly from post egg-hatch L1 instar to L5 instar and pupation in 22 days; adults emerged from pupae (eclosed) in 14 days. Larvae solitary, build small silk nests, older larvae form shelters in folded leaves or a cluster of leaves. Pupation occurs on plant stems or under leaves; overwinter (hibernate) as adults, possibly as pupae (Scott 1979, 1986; Ferris and Brown 1981; James and Nunnallee 2011). Males territorial, perch on shrubs or ground on hilltops, porch roofs, other elevated sites, awaiting passing females (Scott 1975b, 1986; James and Nunnallee 2011).