Grammia nevadensis ( Grote & Robinson, 1866 )

Ferguson, Douglas C. & Schmidt, Christian, 2007, Taxonomic review of the Grammia nevadensis species group (Lepidoptera: Arctiidae) with descriptions of`two new species, Zootaxa 1405, pp. 39-49 : 40

Grammia nevadensis ( Grote & Robinson, 1866)

( Figs. 1 a–d, 3)

Despite the considerable geographic variation in extent and colour of wing markings, we have not been able to find any consistent morphological differences (genitalia, antennae or otherwise) that correlate with the phenotypic differences seen among the taxa nevadensis , geneura , superba and gibsoni . Furthermore, long series of specimens from any given locality often contain phenotypes indistinguishable from other geographic regions. Molecular data show that at least some phenotypically and geographically distinct populations show identical haplotypes of the COI­COII gene regions of mitochondrial DNA (Schmidt, unpublished). Briefly, these results show that populations near the range edges of nevadensis subspecies exhibit mixed Cordilleran/Great Basin (subspecies nevadensis and superba) and Great Plains (ssp. gibsoni ) haplotypes; for example, southeastern Wyoming and southern Alberta gibsoni phenotypes exhibit at least some haplotypes characteristic of subspecies nevadensis and superba. We therefore treat G. nevadensis as consisting of four subspecies: nevadensis , geneura , superba and gibsoni .

G. nevadensis tends to be larger with narrower forewing white bands and more saturated colours in the northern parts of its range. Forewing length ranges from 15­19 mm, averaging 16.3 mm (n = 86) overall, with an average of 16.8 mm (n = 11) for British Columbia and 17.4 mm (n = 5) for Washington populations, compared to averages of 16.0 mm (n = 53) for eastern Oregon and 16.3 mm (n = 15) for western Montana.

Figures

FIGURE 1. Adult males of the Grammia nevadensis species group, a) G. n. nevadensis (Winnemuca, Humboldt Co., NV); b) G. n. superba (Victoria, Vancouver Is., BC); c) G. n. geneura (Estes Park, Larimer Co., CO); d) G. n. gibsoni (Burstall dunes, SK); e) G. behrii (Eight Dollar Mtn., Josephine Co., OR); f) G. i n c o r r u p t a (Comanche Natl. Grassland, Baca Co., CO); g) G. williamsii (Jenner, AB); h) G. eureka (HOLOTYPE, Eureka, Juab Co., UT); i) G. bowmani (PARATYPE, Black Ridge, Mesa Co., CO).