Anthocharis lanceolata, Lucas, 1852

Opler, Paul A., Stout, Todd L., Back, Werner, Zhang, Jing, Cong, Qian, Shen, Jinhui & Grishin, Nick V., 2022, DNA barcodes reveal different speciation scenarios in the four North American Anthocharis Boisduval, Rambur, [Duménil] & Graslin, [1833] (Lepidoptera: Pieridae: Pierinae: Anthocharidini) species groups, Zootaxa 5194 (4), pp. 519-539 : 525

The lanceolata group: deep barcode divergence with limited morphological divergence.

Traditionally considered the single species A. lanceolata with subspecies australis and desertolimbus (e.g. Comstock 1927; Emmel et al. 1998; Opler 1999; Warren et al. 2021), our results show a deep divergence between the CO I of lanceolata including the southern subspecies A. lanceolata australis and A. desertolimbus . These results corroborate Back’s (2010) species-level distinction by our detailed COI haplotype data. Anthocharis lanceolata ranges from 42°north latitude in southern Oregon ( Dornfeld 1980; Hinchliff 1994; Warren 2005) and thence south in the Cascade Province, Klamath Mountains, Trinity Alps, North Coast Ranges, Warner Mountains, and Sierra Nevada of California. Except for an unsubstantiated specimen from near Mt. Diablo, Contra Costa County ( Steiner 1990), the species is absent from the entire south coast range south of San Francisco Bay, California ( Steiner 1990). The species is found on the western slope of the Sierra Nevada in the Transition and Canadian life zones, where it overlaps both A. sara and A. julia (see below). The species is also found sparingly along the lower eastern slope of the Sierra Nevada from the Carson Range of Nevada and other locations in Mono and Inyo counties, California (K. Davenport and J. Emmel, pers. comm.). Its southern terminus seems to be along the Kern River drainage of Tulare and Kern Counties ( Davenport 2004b). Further south, the species continues as the subspecies australis in the Transverse Ranges in the San Gabriel and San Bernardino Mountains of Los Angeles and San Bernardino County ( Figure 21 ).

The butterfly described as A. lanceolata desertolimbus which extends along the desert edge of the Laguna Mountains south into the arid eastern slope of the Sierra Juarez.( Emmel &Emmel 1973),is a distinct species according to our DNA CO I result but genomic sequencing (Grishin lab, unpublished) reveals less genetic differentiation than usually observed for distinct species. A population in the Sierra San Pedro Martir of Baja California Norte, Mexico (30°north latitude) is included with desertolimbus in our results.

Back (2010) has suggested that the A. lanceolata group be considered as two species— lanceolata and its subspecies australis (F. Grinnell) as opposed to the subspecies desertolimbus J. Emmel, T. Emmel and Mattoon found in the desert edge of the Colorado Desert in San Diego County, California, which Back considered as a separate species. His decision was based on some phenotypic differences between these populations together with some differences in mitochondrial genes.

Back’s description of these characters included large size of typical lanceolata Lucas , together with an extended forewing apex, lightening of forewing apical markings, a half-moon shaped black discal spot, and contrasting darkened veins on the ventral hindwing. These stand in contrast to smaller size of the more southern desertolimbus together with its lack of extended forewing apex, darker apical forewing maculation, reduced discal black spot, and barely darkened ventral hindwing veins. In addition, Back found that the pupae of A. desertolimbus lack the scattered tiny black spots.

Additionally, there appear to be some larval differences between A. lanceolata , including subspecies australis , and A. desertolimbus . In later instars of A. lanceolata , including subspecies australis , there are 6 shallow annulets per abdominal segment, whereas in late instar larvae of A. l. desertolimbus there are 7-8 deeper annulets per abdominal segment. Moreover, there seem to be minor color pattern differences in the advanced instar larvae. Larvae of all populations have a subspiracular lateral band of yellow subtended by white. In A. lanceolata , included australis , both components of this band are relatively even in width throughout, whereas, in contrast, on late instar larvae of A. l. desertolimbus , the yellow portion of the band is uneven in width throughout.

An additional factor arguing for the distinctness of Anthocharis desertolimbus is its occurrence in low elevation desert-like habitats along the western Colorado Desert edge and Laguna Mountains of San Diego County, California and the eastern desert edge of the Sierra San Pedro Martir of Baja California Norte, Mexico.

Our thought on how to represent the taxonomic status of these named and un-named entities is that it may be an individual choice. Our perception of larval differences and CO I would lean toward treating A. lanceolata and A. desertolimbus as separate species-level entities, whereas genomic results and the seeming clinal relationship of adult characters would lead one to treat all of these populations as conspecific. Occasional rare field-collected individuals appear to be intermediate between A. sara and A. lanceolata ( Comstock 1929; Shields & Mori 1979; Warren 2005). We have not personally examined or sequenced these specimens and their barcodes are unknown.

Figures

FIGURE 21. Distribution of Anthocharis lanceolata group, six-pointed stars—nominotypical lanceolata, yellow-filled circle—southern Sierra Nevada lanceolata and subspecies australis, orange-filled circles—desertolimbus and San Pedro Martir population.