Holarctia, M. E. SMITH, 1938

Schmidt, B. Christian, 2009, Taxonomic revision of the genus Grammia Rambur (Lepidoptera: Noctuidae: Arctiinae), Zoological Journal of the Linnean Society 156 (3), pp. 507-597 : 515-517

GENUS HOLARCTIA M.E. SMITH

Holarctia M.E. Smith (1938b: 6) . Type species: Callarctia turbans ( Christoph, 1892) [junior subjective synonym of Arctia obliterata Stretch, 1885 ], by original designation.

Diagnosis: Apical, flat portion of male valve highly reduced, base of the valve costa produced inwardly, apical chamber of vesica equal to or smaller than median chamber, apex of aedeagus spiculate laterally, juxta approximately as wide as long and lacking lateral spicules. Ductus bursae of female with apical portion evenly sclerotized and roughly cylindrical, lacking membranous medioventral break seen in Grammia ; number of signa of corpus bursae varying from none to three; appendix bursae short, broad, and not strongly recurved as in Grammia . Unlike Grammia , the forewing transverse bands never extend beyond vein CuA towards the anal margin.

Remarks: Although Arctia obliterata Stretch has invariably been treated as congeneric with Grammia (e.g. Forbes, 1960; Franclemont, 1983; Ferguson, 1984, 1985, 1991; Dubatolov, 1996), Smith (1938a) recognized that it was very divergent morphologically from all other Grammia species , despite superficial similarity in wing markings (particularly to Grammia virguncula ). This led her to propose a new subgenus for G. obliterata , i.e. Holarctia M.E. Smith , which was re-instated as a valid genus by Schmidt & Opler (2008).

I initially believed Holarctia and Palearctia Ferguson to be congeneric ( Schmidt, 2007), and the two were subsequently synonymized ( Schmidt & Opler, 2008). Characters that Holarctia obliterata shares with, and are diagnostic for Palearctia (as defined by Ferguson [1984]), include the highly reduced apical flat portion of the male valve ( Ferguson, 1984: 454, figs 12–14) (prominent and lobate or spatulate in Grammia ), base of the valve costa produced inwardly ( Ferguson, 1984: 454, figs 12,13,14) (absent in Grammia ), apical chamber of vesica equal to or smaller than median chamber ( Ferguson, 1984: figs 12a, 13a, 14a) (large and kidney-shaped in Grammia ), apex of aedeagus spinulate ( Ferguson, 1984: 454, figs 12a, 13a, 14a) (unmodified in Grammia ), ductus bursae of female lacking medioventral membranous break of sclerotized apical collar ( Ferguson, 1984: 454, fig. 16) (present in Grammia ), corpus bursae with three signa ( Ferguson, 1984: 454, fig. 16) (four in Grammia ).

Examination of additional Palearctia species , molecular data (B. C. Schmidt, unpubl. data), and Palaearctic specimens of H. obliterata show that Holarctia and Palearctia form separate evolutionary lineages and are in fact not closely related. The reduced, flat valve apex appears to be homoplasious, in that it is formed by an extension of the costa in Holarctia , but not in Palearctia (V. Dubatolov, pers. comm.). The basal inward projections of the costa, spinulate aedeagus, and entirely sclerotized corpus bursae apex appear to be ancestral character states within the entire group of genera (subsequently lost in Grammia ), and are therefore not synapomorphic for Holarctia + Palearctia . Furthermore, Palaearctic populations of H. obliterata exhibit a nonspinulate aedeagus and the signa bursae vary in number from zero to two (V. Dubatolov, pers. comm.). For these reasons, both genera should be retained as valid, with Palearctia stat. rev. related to the Neoarctia – Holoarctia group ( Ferguson, 1984), and Holarctia related to (and likely to be basal to) the Grammia – Apantesis group of genera ( Schmidt, 2007).

The large genetic divergence of obliterata from Grammia species ( Fig. 133 ), and nonmonophyly of Grammia s.l. ( Schmidt, 2007) also support recognition of Holarctia as a separate genus, although it is unfortunate that Holarctia Smith and Holoarctia Ferguson not only have a confusingly similar orthography, but also species with superficially similar phenotypes. Ferguson (1984) remarked: ‘I am aware that the spelling of Holoarctia is similar to that of Holarctia M.E. Smith , a synonym of Grammia Rambur (Arctiidae) , and Holarctias Prout , a synonym of Scopula Schrank (Geometridae) , and that it disregards a recommendation of the Code that names with small differences of spelling be avoided. However, it is not a homonym.’

HOLARCTIA OBLITERATA (STRETCH) STAT. REV.

(FIGS 3, 40, 74, 96)

Arctia obliterata Stretch, 1885: 105 .

Arctia turbans Christoph, 1892: 460 . Apantesis turbans (Christoph) ; Franclemont, 1983: 117.

Grammia obliterata (Stretch) ; Ferguson, 1991: 1.

Grammia obliterata (Stretch) ; Ferguson & Opler, 2006: 9.

Type material: Arctia obliterata : holotype male [ CAS] illustrated in Ferguson (1991) (photograph examined); the type locality is unknown, and presumed to be western North America .

Arctia turbans : male holotype in ZIN according to Ferguson (1991) (not examined); the type locality is the ‘ Tunga-Alpen, süd-westlich von Irkutsk’ .

Diagnosis: Likely to be confused only with Grammia virguncula in North America, from which it can usually be distinguished by the presence of two or more pale bars in the costal and/or discal area of the forewing, which are very rare in virguncula . The forewing anal and cubital lines never extend to the wing margin in obliterata , nearly always in virguncula . Genitalic differences are discussed under Holarctia .

Description: Head – Palps black, frons and vertex pale to yellowish buff, vertex rarely black centrally; male antennae moderately bipectinate, rami averaging 5.55 ¥ 10 - 1 mm, (N = 6); female antennae moderately biserrate; dorsal scales dark brown to black; eyes well developed, slightly reduced with partially exposed gena in YT specimens. Thorax – Vestiture black with pale to yellowish buff borders on vertex, patagia and tegulae; black to yellowish buff ventrally, legs predominantly pale buff, ringed with black at base of segments, giving striped appearance. Abdomen – Dorsal ground colour dull yellow, pale buff near apex; medial and lateral markings black; medial spots often expanded laterally, sometimes confluent with lateral spots such that ventrum is entirely black with yellow segment margins; pale yellowish buff ventrally, lateral black markings varying from discrete oblong spots to entirely confluent with only distal margins of segments pale. Forewing – Male forewing length averaging 14.8 mm (N = 6 males); black dorsally, vein lines nearly complete, rarely extending through apical area; anal vein line rarely extending beyond halfway to anal angle; lines and bands yellowish buff to pale whitish buff; cubital vein line slightly broader than other vein lines; antemedial, medial and postmedial bands reduced to costal/discal bars or absent, never extending beyond cubital vein (postmedial very rarely so, as fine line); subterminal band complete; ventral markings similar, but dark markings with a paler yellowish cast and pale markings slightly more diffuse; sexes similar. Hindwing – Ground colour deep, dull yellow, rarely varying to orange; black markings variable in extent, but antemedial elements usually lacking, medial spot prominent; postmedial spots well developed, varying from discrete to partially or entirely confluent with irregular subterminal band; ventral markings similar, but dark markings with a paler yellowish cast; sexes similar. Male genitalia – Distal portion of valve highly reduced, such that the pronounced, pointed clasper appears as valve apex; median ridge pronounced; uncus broad-based, process evenly tapered to rounded apex; juxta twice as long as wide, dorsal margin sinuate, convex medially; aedeagus with slight dorsad curve at 2/3 distance beyond base; vesica highly reduced in length and width; basal and medial chamber only slightly wider than width of aedeagus; basal chamber scobinate and slightly sclerotized laterally; distal chamber only slightly larger than medial chamber, very faintly scobinate. Female genitalia – Ostium bursae with sclerotized collar; ductus bursae short, corpus bursae arising very near ostium; corpus bursae globose to teardrop-shaped, two to three¥ width of ostium; three scobinate signa, signum 1 larger than 2 and 3; appendix bursae coiled, evenly tapered; posterior apophysis twice length of papillae anales.

Biology: In North America, Holarctia obliterata inhabits grasslands in dry montane habitats and the northern prairies. It prefers habitats with sparse vegetation cover, such as sandy substrates, eroding slopes, and gravel outwashes. Most adult collection dates range from mid July to mid August, and in the northern parts of its range, obliterata often flies with Grammia nevadensis . Both sexes come to light, although females rarely so. In YT (and probably AK), obliterata is diurnal, and males have a rapid, buzzing flight (G. Anweiler, pers. comm.).

Distribution: Holarctic in distribution. In North America, occurs from AK and southern YT, and primarily east of the Continental Divide from northern BC to northern CO and UT ( Ferguson, Opler & Smith, 2000), east to MB ( Fig. 96 ). The record for Great Bear Lake, NT in Ferguson (1991) is based on an aberrant specimen of Grammia virguncula . In the Palaearctic region, obliterata occurs from Russia (Khakassia, East Sayan, Baikal region, Transbaikalia, Amurland, Yakutia) to Mongolia ( Murzin, 2003).

Molecular variation: Three specimens of obliterata from two sites ( AB) exhibited three haplotypes, at least 5.33% divergent from all Grammia haplotypes, with a maximum intraspecific divergence of 0.15% ( Table 2).

Remarks: The specimen illustrated as a female Holarctia obliterata by Murzin (2003: 214) is not H. obliterata , and appears to be another species of Holarctia or Sibirarctia Dubatolov.

Figures

Figure 133. Neighbour-joining tree of cox1 ‘barcode’ haplotypes of Grammia species and Holarctia obliterata. Two-letter codes correspond to the species name in a given lineage. The Kodara Lineage includes Grammia quenseli (QE1), Grammia williamsii (WI1), and Grammia virgo (VI14) haplotypes. Haplotypes of the Western and Eastern lineages are shown separately in Figs 134 and 135, respectively. Numbers in parentheses indicate number of sampled specimens.

Figures 96–101. Distribution of examined specimens of Holarctia and Grammia.