Cornus interior, HIGHLANDS AND APPALACHIAN A. DIANA

Pavulaan, Harry, 2021, Subspecific designation of the U. S. A. Interior Highlands population of Argynnis (Speyeria) diana (Cramer, 1777) (Nymphalidae: Heliconiinae: Argynnini: Argynnina), The Taxonomic Report of the International Lepidoptera Survey 9 (9), pp. 1-14 : 2-4

COMPARISON OF INTERIOR HIGHLANDS AND APPALACHIAN A. DIANA

Wells et al. (2018) conducted a thorough geometric morphometric analysis of the two A. diana regional populations and found significant regional differences in male forewing and hindwing shape, and concluded that wing shape of adults can be used as a character to measure population-level differences. Males from the Appalachian Mountains were determined to have narrower and more angular wings, believed to support high dispersal behavior, vs. Interior Highlands males which have rounder wings, supporting low dispersal behavior. The authors also found significant differences in female forewing shape, not regionally, but between high and low elevation populations, where high elevation females possessed narrower forewings than those from low elevations. Unfortunately, they did not specify in which region(s) this female forewing character occurred or was most prominent [it is my interpretation females found in the remainder of diana’s range, including the Interior Highlands region].

My own detailed analysis of adult morphology from both regions shows virtually no consistent differences in wing marks in the males. The range of variation in both Interior Highlands and

Appalachian males, including coloration and extent of all dorsal and ventral markings, appears to fully overlap range wide.

Preliminary measurements of my collected series of males from both Arkansas (n=18) and Virginia (n=16) similarly show little difference in wing shape, with both series showing a high degree of variability [certainly not at the scale of investigation of the

Wells et al. (2018) study, but worthy of note, and supports the argument that large series are often needed to make reliable conclusions]. However, two males were selected, one from each region, each with similar forewing length, and measurements were made, which corroborate the findings of Wells et al. (2018). The red-outlined silhouette (ex Needmore, AR) is overlain with the blue-outlined silhouette (ex Longdale Furnace, VA) (Fig. 1). Both specimens have identical forewing length (measurement A) at 43

mm. Measurement B (Virginia) is 26 mm, and measurement C Fig. 1. A. diana male wings comparison. (Arkansas) is 29 mm, confirming that Appalachian males have narrower forewings than their Interior Highlands counterparts. The hindwing of the Arkansas specimen is measurably larger than the Virginia specimen, measuring 35 mm (measurement E) along vein Cu 1, whereas the Virginia specimen measures 33 mm (measurement D). A visual representation of the male wing shape difference is shown below ( Fig. 2) [same specimens measured for Fig. 1]. Difference in forewing shape is most evident. Overall, Arkansas males (n=24) averaged 45.8 mm forewing length, while Appalachian males (n=58) averaged 43.7 mm (2.1 mm smaller). Arkansas females (n=12) averaged 55.2 mm while Appalachian females (n=21) averaged 51.5 mm (3.7 mm smaller). A study by Showalter & Drees (1980), using an unspecified sample size of Appalachian diana indicated forewing lengths averaging 44.1 mm for males and 52.3 mm for females, each slightly larger in size than the present sample.

both regions, they did not study differences in wing markings. Analysis of male wing marks from both regions in the author’s personal collection, various printed literature sources ( Table 1), and a selection of 196 images [clearly-focused perpendicular views of fresh individuals, not sun-backlit and no shadows on wings] posted to the internet via butterfliesandmoths.org, butterfliesofamerica.com, and iNaturalist.org ( Table 2) corroborates no consistent differences in dorsal or ventral wing marks in males beyond a wide range of individual variation matched in both regions.

Additionally, the Wells et al. (2018) study determined that females expressed a different degree of wing shape development based on elevation, where low elevation females have wider forewings than those from high elevations, reflective of dispersal and host-locating habits. The authors also did not identify any differences in wing marks among females from both regions, for their study. However, my own detailed analysis of female wing mark characters, utilizing the same sources listed above ( Table 2), did find that there is one character that might be considered useful in differentiating some females from both regions. Females from the Appalachian populations generally displayed consistently whitish-blue coloration in the submarginal band of rectangular marks in the subapical area of the forewing (dorsal side), while females from the Interior Highlands populations showed a tendency toward tan to whitish-tan coloration of these rectangular marks. This tendency for tan coloration in the subapical area of the forewing is not seen in all Interior Highlands females examined, but is rarely encountered in Appalachian females. [One problem encountered is the quality of published and web-sourced images. Lighting and focus often distorts the true color of wing marks.]

An earlier study ( Dunford, 2007), which constructed a phylogeny of Speyeria based on 653 characters of the mitochondrial gene COI, placed Arkansas diana separately from West Virginia diana . The two sampled Arkansas diana were identified with 657 COI base pairs, whereas the two West Virginia diana were separately identified with 643 and 657 COI base pairs. Several phylograms of the Speyeria ( Dunford, 2007: Figures 3-8 through 3-11) were constructed for strict consensus trees, all consistently showing the two Arkansas samples grouping together, separated from the two West Virginia samples.

More recently, the Wells (2014) and Wells et al. (2015) studies found significant differences in mtDNA haplotypes between Appalachian and Interior Highlands populations, with eastern populations showing high levels of genetic diversity and Interior Highlands populations with less genetic diversity. Different haplotypes were found to dominate the Appalachian and Interior Highlands populations ( Wells, 2014; Wells et al., 2015), with ‘haplotype 1’ dominating the Interior Highlands population and ‘haplotype 2’ dominating the Appalachian population. Wells et al. (2018) concluded that morphological and mitochondrial DNA differences between the two regional populations “may warrant subspecies designation”.