Speyeria atlantis irene

Some authorities now consider our populations a separate species, S. hesperis, which is then called the Northwestern Fritillary. A common species of relatively moist montane forest and roadsides, on our transect only a rare stray below 6000' but probably the commonest Speyeria at Donner and second-commonest at Castle Peak (after the more dryland-adapted S. egleis). An eager flower visitor, often seen at Aster, Coyotemint, and early-blooming Rabbitbrush. One brood in midsummer, a few still flying well into autumn. Hosts Violets (species preferences unknown).

Speyeria callippe juba

This is the Sierran west-slope subspecies, with a ruddy ventral hindwing and variable silvering. As usual for callippe it is the first Fritillary to emerge in a given locale, and usually the first to disappear. It is an avid visitor to flowers of Yerba Santa, Pink Dogbane, and Coyotemint and even to late flowers of Pussy Paws. Males also puddle. Fairly common at Washington and Lang (May-July). Larval host plants violets; at least at Washington these have often senesced by the time eggs are laid.

Speyeria callippe nevadensis

The Sierran East Slope subspecies, with greenish hindwing disc below; spots heavily silvered. Looks like a small S. coronis! On our transect occurs only at Sierra Valley, flying early like other callippe (June-July); visits Thistles, Alfalfa and yellow Composites. A moist-meadow species, presumably feeding on moist-meadow violets. Another colony occurs at the Donner Camp historic picnic site north of Sierraville on Highway 89.

Speyeria callippe ssp.

Three subspecies occur on our transect. Speyeria callippe juba is strongly reddish beneath, with varying degrees of silvering. It occurs on the Sierran West slope, at Washington and Lang Crossing, and may be quite common in mesic forest and successional sites, where it visits Pink Dogbane, Giant Hyssop, Yerba Santa, Coyotemint, Wild Buckwheats and other flowers freely. Speyeria callippe nevadensis occurs on the East slope and on our transect is found only at Sierra Valley.

Speyeria coronis

A large, showy, heavily-silvered Frit occurring in the Sierra Nevada but also in the Coast Range and even (as a stray?) in the Valley and Delta.

Speyeria cybele leto

Our largest Frit, and the one showing the most dramatic sexual dimorphism. Leto is widespread at and above 5000' but is never common; many populations seem to be at very low density-just a few pairs per year. The preferred habitat is moist meadows adjacent to forest. Females wander a great deal and often turn up far from "home." There is one brood (July-October; late in the season one sees only females). The hosts, as always for Speyeria, are undetermined Violets.

Speyeria egleis

Fairly common at Donner and very common near tree-line on Castle and Basin Peaks. A fairly small Frit, about the size of S. mormonia, but unlike it found usually in relatively dry sites, often in areas dominated by Lodgepole Pine; adults visit Coyotemint, Aster, thistles, etc. and males both puddle and hilltop. Although this species is famously variable, it shows little variability on our transect. Like all Frits single-brooded (June-October); host plants Viola, species preferences unknown.

Speyeria hydaspe

A bright-orange, medium-sized Frit, strongly purplish below (and in our area, nearly unsilvered), limited to mid-elevations on the Sierran West slope where it is common at Lang, occasional at Washington and only an infrequent stray at Donner. A species of mixed-mesic forest, commonly seen along roadsides and in successional stands where it visits Pink Dogbane, Giant Hyssop, milkweeds, Yerba Santa, etc. It frequently co-occurs with S. callippe juba and S. zerene, but generally below S. egleis, mormonia and atlantis. One brood, June-September.

Speyeria mormonia

A small Frit, delicately marked, well-silvered, with rounded wings and a golden-ruddy cast on the hindwing beneath, found at high elevation mainly on and near grassy meadows. Common at Donner; at Castle Peak mainly on Castle Valley. Flies low; visits Aster, Rabbitbrush, Coyotemint, etc. A rare stray at lower elevations. This species typically emerges rather late (Late July-August) and flies well into autumn (October). The hosts are Violets; specific preferences are unknown.

Speyeria zerene

On our transect, a rather uncommon species but seen at all the Sierran sites mainly in the second half of the season; females often fly well into autumn. Visits Giant Hyssop, Thistles, Milkweed, Alfalfa, Rabbitbrush and other rather tall flowers. All of our populations, including Sierra Valley, are very ruddy above and purplish beneath and well-silvered ("near conchyliatus"). As in all Speyeria, one brood; larval hosts Violets, species undetermined. A species of meadows, wood roads and open conifer forest.