Art Shapiro's Butterfly Site - Satyrium

Satyrium auretorum

admin — Sun, 28 May 2006 18:07:42 +0000

Formerly present on the Sacramento Valley floor but now extinct at both North Sacramento and Rancho Cordova. Common in foothill woodland in the lower Coast Range and Sierra Nevada , usually seen in good numbers visiting flowers of California Buckeye. This and the California Hairstreak are the first species of Satyrium to emerge in the foothills. There is one brood, from the end of April to late June. Females may have quite a bit of orange above.

On the Sierran West slope at mid-elevation occurs a conspicuously larger and better-marked race of S. auretorum which is always scarce and does not show up every year at Lang. It flies in June and July and has been found nectaring on pink dogbane, Yerba Santa and Eriogonum nudum.

The host plants are a variety of Oaks (Quercus). At Lang the host is Black Oak (Q. kelloggii).

Satyrium behrii

admin — Sun, 28 May 2006 18:07:41 +0000

An east-slope species, abundant and breeding at Sierra Valley, straying to Donner (where no hosts are present). It flies in late spring-early summer (May-July) and visits Eriogonum nudum, E. umbellatum, Milkweeds, Alfalfa,Yarrow (Achillea), Yellow Ivesia and other flowers - sometimes in great numbers and often in the company of the Juniper Hairstreak. The host is Bitterbrush or Deer Brush, Purshia tridentata (Rosaceae).

This butterfly is recorded intermittently on Castle Peak at 9000', usually very late in the season (September). There is a matted, prostrate ecotype of Purshia along the ridgeline. The seasonality argues against these butterflies being flyups from below and suggests breeding in situ. We do not know if this is an ongoing, resident population or a case of recurrent short-term colonization. For the record, there is a population of Behr's Hairstreak on a shrub-steppe bench along the Truckee River directly across from downtown Truckee that emerges every year as late or later - even into early October! Its only nectar source at that time is a local (and very showy) late-blooming ecotype of Eriogonum umbellatum. On Castle Peak in September it is very hard to find anything at all in bloom!

Satyrium californica

admin — Sun, 28 May 2006 18:07:40 +0000

This species has a variety of ecological races, or ecotypes. On the floor of the Sacramento Valley, where it is nearly extinct, it feeds on Valley Oak (Quercus lobata) and visits Hoirehound (Marrubium) and Dogbane (Apocynum cannabinum) flowers almost exclusively. Valley specimens are lustrous and sharply-marked beneath. Foothill ones, which seem to breed on a variety of oaks, average slightly smaller, less lustrous and less sharply-marked; they are usually very abundant and visit California Buckeye very heavily. Montane West-slope populations may breed on Black Oak (Quercus kelloggii) at lower elevations and on Tobacco Brush (Ceanothus velutinus) and perhaps other Ceanothus at Donner. The East-slope ecotype found at Sierra Valley is large, dark, strongly marked and breeds on Mountain-Mahogany (Cercocarpus ledifolius)! It usually shows up on Milkweed flowers, occasionally on Sulphur Flower, Sweet Clover, or Alfalfa. There is one brood, flying near sea level from late April-late June, at Sierra Valley June-July, at Donner (usually) late July-early September. Always overwinters as egg.

This species and the other species of Satyrium partition the day. We do not know where they are early in the morning. They nectar from late morning to mid-afternoon and then become territorial in late afternoon, perching on or near the host plant.

Satyrium fuliginosum fuliginosum

admin — Sun, 28 May 2006 18:07:39 +0000

This is interpreted as the entity occurring on Castle Peak and on a tiny area of Donner Pass. It is larger and darker than subspecies semiluna, and the males lack a stigma. Males perch territorially,often on the matted ecotype of Bitterbrush (Purshia) growing along the ridgetop between Basin and Castle Peaks. Females walk a lot. Both sexes often visit Mule's Ears (Wyethia mollis) flowers, as well as Sulphur Flower (Eriogonum umbellatum). One flight in the second half of the alpine season, generally July-September. At Donner often in June, and disappearing quickly (presumably because the colony is so small). Host plants, perennial species of Lupinus, including L. arbustus and L. albicaulis.

Satyrium fuliginosum semiluna

admin — Sun, 28 May 2006 18:07:38 +0000

This subspecies is a little smaller and grayer than nominate fuliginosum, and the male has a stigma. It occurs widely in the central and southern Sierra and in the northern Great Basin. There is at least one population in Siera Valley which, however, has only been found once at our study site. Males perch atop sagebrush in the midst of shrub-steppe. Both sexes can be found far from any blooming nectar sources, but they do visit Yarrow, Brassicaceae (e.g. Cardaria pubescens) and Sulphur Flower (Eriogonum umbellatum).

Satyrium saepium

admin — Sun, 28 May 2006 18:07:37 +0000

Usually common to abundant where found, the Sepia Hairstreak emerges last among our Satyrium species and often flies quite late in the season, especially at higher elevations. Like all the Satyrium it has only one brood a year, wintering as the egg. There is no significant variation in or among our populations. Visits flowers, including Wild Buckwheat and Rabbitbrush. The hosts are various species of Ceanothus. June-July at Gates Canyon and Washington, mainly July at Lang, and August to October(!) at Donner. Males are territorial perchers in late afternoon.

Satyrium sylvinus

admin — Sun, 28 May 2006 18:07:36 +0000

Distributed from sea level to near tree-line, but mysteriously absent from many places where its hosts are abundant. On the other hand, local colonies are very persistent-in some cases seemingly centered on individual trees. This species was incredibly abundant in the Sacramento Valley in the 1970s but is now teetering on the brink of regional extinction for no obvious reason. Its numbers also seem to be decreasing in the mountains.

The Willow Hairstreak is very variable. On the upper surface individuals may have no orange (except for the anal spot) to a great deal. On the under surface the gray color may be matte or lustrous and the black dots may be well-defined and dark (most montane populations) to obsolescent (many Valley ones). There is variation both within and among populations. In the Livermore area and in the western Great Basin this species is tailless and has been considered a separate species, dryope, though it is not known if butterflies from the two areas are "really" the same entity. There are no dryope on our transect, though many Valley animals look like dryope with tails. Dryope occurs as close to us as Carson Valley (Gardnerville and Minden, NV).

One brood, May-July at low elevations, July-September at Donner. Males perch terriotorially on the host plant. An avid visitor to Dogbane, Milkweed, Eriogonums of the nudum group, Yarrow, members of the Apiaceae, etc. As late as the 1980s it was possible to see several hundred Willow Hairstreaks at once on tall Dogbane (Apocynum cannabinum) in the riparian zone in West Sacramento or North Sacramento. Today they are gone completely at West Sac and rare at North. Only a handful of presumed strays have been taken at Rancho Cordova, though willows are superabundant in the jumbled post-dredging gravel landscapes.

Different populations seem to "specialize" on different willow species. Even in the Sacramento Valley, some feed on glabrous, green-leaved willows and others on the gray-pubescent Sandbar Willow. Near Vacaville, including Gates Canyon, the foothill-riparian populations have lustrous undersides and feed on green willows, while the Valley floor ones are matte and use Sandbar Willow. We have much to learn.

This species apparently bred briefly at Castle Peak but is not a regular member of that fauna.

Satyrium tetra

admin — Sun, 28 May 2006 18:07:35 +0000

On the transect, this species is disjunctly distributed, occurring in Gates Canyon, where it is uncommon, and at Sierra Valley, where it is abundant. Both populations feed on Mountain-Mahogany (Cercocarpus): Gates on the foothill species, C. betuloides, a chaparral shrub, and Sierra Valley on C. ledifolius, found in rocky habitats in East slope shrub-steppe and often at or near tree-line in arid climates. The Sierra Valley animals, especially females, are larger than at Gates. There is one brood, in June-July at Gates, July-August at Sierra Valley. Males are territorial perchers, usuallty on or near the host plant, forming leks in the afternoon. Both sexes visit flowes: at Gates on Yerba Santa and California Buckeye, at Sierra Valley on Alfalfa, yellow Ivesia, Eriogonum, White Sweet-Clover, Milkweed, etc. The host plants - and the butterfly - occur at none of the other sites.