In Desert Marbles the green marbling on the ventral hindwings is never tinged with yellow. The marbling occurs in large patches with substantially smaller, pearly white areas between them. The forewings and hindwings of both sexes are always completely white. The black discal cell spot on the forewing does not have any white scales in it, and is large and square (Opler 1970).
Eggs and young larvae are similar to those of the Large Marble. Third to fifth instar larvae are green above and below the spiracles, with few or no black spots except on the head. There is a narrow purplish stripe above the spiracles, and sometimes down the back. There is a white stripe along the side at the spiracles, and the head is green. Larval colour is geographically variable, with the basic green colour sometimes being greyish or yellowish green in some populations. The prepupal larva is dark purple with a prominent white stripe down each side. The elongated head end of the pupa is hooked (Opler 1975).
None. The species was named from "Colorado, Arizona, Utah, southern California." Until recently the Desert Marble was treated as a subspecies of the California Marble, Euchloe hyantis (W.H. Edwards, 1871), but is now recognized as a full species. Desert Marbles are pure white above, and have a wider forewing discal black bar and a somewhat square forewing. The white areas of the ventral hindwing are distinctly pearly iridescent. In contrast, California Marbles are off-white above with a narrow forewing discal black bar, and have a pointed forewing; the white area of the ventral hindwing is only slightly pearly iridescent (Opler 1999).
The name Euchloe was written as Euchloë until the taxonomic code eliminated the use of diacritical marks. The name is apparently composed of the Greek eu (good) and khloë (light green colour of spring vegetation), referring to the green marbling on the ventral hindwings (Emmet 1991). The common name refers to the green marbling on the ventral hindwings.
The three species of marbles in BC are all small white butterflies with black markings on the upperside of the wings and a pattern of greenish marbling on the ventral hindwings. Marbles are generally found east of the Coast Range in BC. The most recent review of the genus Euchloe was by Opler (1967b, 1967c, 1967d, 1967e, 1970, 1971, 1975).
Eggs are greenish or cream white when laid, and then soon turn bright orange. Eggs are columnar, with the micropylar area broadly rounded. There are 15-20 prominent vertical ridges, connected by less prominent horizontal ridges. Larvae are green with longitudinal stripes, becoming purplish when prepupal. Pupae are variable shades of brown; they are long and slender, and the head end tapers to a narrow tip. A girdle holds the pupa head up and tightly against a stem.
Marbles lay eggs and feed on the leaves, stems, or flowerheads of Brassicaceae, especially Arabis, that are bolting into flower. Preferred plants grow in full sunlight and are more than 12 cm in height with an erect configuration. Young larvae feed on leaves or within flower buds or inflorescences of flower buds. Older larvae feed externally on seed pods (Opler 1975). Marbles hibernate as pupae, and all have only a single spring brood.
Desert Marbles are on the wing in April and May, with only one brood each year. Oviposition is on flower buds, leaves, or stems of Brassicaceae. The first instar larvae move immediately to the flower buds to feed, either by walking over the plant surface or by boring through the leaves clasping the inflorescence. The larvae then bore through the side of the flower petals, enter, and feed on the inside of the flower (Opler 1975). Where they occur close to each other in the US, Desert Marbles fly earlier than California Marbles, Euchloe hyantis. Desert Marbles lay eggs on, and larvae feed on, a wide range of crucifers, whereas California Marbles use species of Streptanthus as larval foodplants almost exclusively (Shapiro 1982b). Desert Marbles in Benton County, WA, use Descurainia pinnata and Sisymbrium altissimum as larval foodplants (Opler 1975).
Desert Marbles occur in the arid lowland grasslands of the Southern Interior and Kootenays of BC.
Desert Marbles occur from southern BC south through the transmontane Columbian drainage, Great Basin, and Colorado plateau to north-central MEX (Opler 1999).
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
22/11/2019 4:15:26 AM]
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