Desert Marble (Euchloe lotta) (Beutenmüller, 1898)

Diagnosis: The Desert Marble is relatively small (wingspan: 38 to 40 mm) and differs from the other marbles in having a pearly sheen on the white shading on the underside of the hindwing, although this can be difficult to observe, especially in worn specimens. It is most easily identified by the shape and colour of the rectangular black bar on the leading edge of the forewing (the discal spot); in lotta this spot is black without any white speckling of scales on it and it is broad and rectangular with the end of the spot usually abruptly squared off. The sexes are similar, except the discal spot tends to be wider, sometimes almost square, in females.

Range: In Canada the Desert Marble is most characteristic of the interior of British Columbia, particularly the Okanagan Valley. There are, however, several records from near the Alberta border (Cranbrook and Yoho National Park). Reports of this species from Yukon were based on misidentified specimens. In the United States it is widely distributed in the Great Basin region and into southern California, and northern Mexico.

Similar Species: All other Euchloe; see Large Marble (E. ausonides). [compare images]

Early Stages: The green larva has a white lateral line bordered with purple and many small black dots. The foodplants are a wide variety of plants in the mustard family.

Abundance: The Desert Marble tends to be local, but can be numerous at some sites (Dornfeld, 1980).

Flight Season: In the southern interior of British Columbia the Desert Marble flies in April and May.

Habits: This is a butterfly of dry desert and sagebrush areas and open, rocky woodlands.

Remarks: Published and more recent research by P.A. Opler indicates that the Desert Marble (E. lotta) of the Great Basin and deserts of southern California is a separate species from the California Marble (E. hyantis (W.H. Edwards)). There are no intermediates found where the ranges of the two species abut and there are subtle structural differences and different larval foodplants (Paul Opler, pers. comm.).

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.