Chlosyne palla sterope (W. H. Edwards, 1870)

Zhang, Jing, Cong, Qian, Shen, Jinhui, Song, Leina & Grishin, Nick V., 2025, Update to: Advancing butterfly systematics through genomic analysis, The Taxonomic Report of the International Lepidoptera Survey 12 (6), pp. 1-36 : 3

Chlosyne palla sterope (W. H. Edwards, 1870) and Chlosyne flavula blackmorei Pelham, 2008 : illustrations of selected sequenced specimens

Here, we compile photographs of several specimens of both sexes that were included in the phylogenetic tree published as fig. 2 in Zhang et al. (2025a) to illustrate phenotypic variation and interspecies differences in the northernmost populations of the two species: Chlosyne palla (Boisduval, 1852) (type locality in USA: California, Plumas Co.) and Chlosyne flavula (W. Barnes & McDunnough, 1918) (type locality USA: Colorado, Garfield Co., Glenwood Springs ) ( Zhang et al. 2023c, 2025a), specifically, Chlosyne palla sterope (W. H. Edwards, 1870) (type locality in USA: Oregon, Wasco Co.) and Chlosyne flavula blackmorei Pelham, 2008 (type locality Canada: British Columbia, Lytton) ( Fig. 1). The two species are best differentiated by females: C. palla sterope is typically darker with cream-colored to nearly white spots and bands and usually a more elongated forewing apex; and C. flavula blackmorei has orange and orange-yellow spots and bands and a rounder forewing apex.

We were not able to find consistent wing pattern differences between the northern populations of C. palla sterope ( Canada: British Columbia, Osoyoos and USA: Washington, Okanogan Co.) and its more southern populations ( USA: Washington, Adams Co. and Oregon, Wasco Co.), with some specimens being rather similar (e.g., compare Fig. 1d with Fig. 1l or Fig. 1m for males, and Fig. 1g with Fig. 1q for females). Females are particularly alike. However, males from the northern populations are more variable, with some being more extensively orange (e.g., Fig. 1j) than typical C. palla sterope , or exhibiting cream-colored (rather than orange-yellow) discal bands ( Fig. 1o). Genetically, all these specimens cluster together, forming a nuclear genome clade that also includes the lectotype of C. palla sterope (sequenced as NVG-21011C11 and used to assign this name to the clade), but partition into the northern and southern subclades; see fig. 2 in Zhang et al. (2025a).