Lithosarctia witti Volynkin & Saldaitis, 2018

Volynkin, Anton V., Saldaitis, Aidas & Višinskas, Vytautas, 2018, A brief review of the genus Lithosarctia, with the description of a new species from China (Lepidoptera, Erebidae, Arctiinae), Zootaxa 4444 (5), pp. 561-574 : 563-564

Lithosarctia witti Volynkin & Saldaitis , sp. nov.

( Figs. 3–8 , 22, 23 , 29 )

Type material. Holotype ( Figs. 3 , 22 ): ♂, China, East Tibet, Qamdo, Dhamo La , 3900 m, 13–20.VI.1996, leg. Westphal, slide MWM 33701 Volynkin (Coll. MWM/ ZSM).

Paratypes: 1 ♂, same data as in the holotype (Coll. MWM/ ZSM) ; 1 ♀, China, W Sichuan, Shaluli Shan , 40 km NW from Daocheng, H – 4060 m, N 29°17.401’ E 100°05.068, 12–13.V.2016, Saldaitis leg. (Coll. AFM) ; 4 ♂, 4 ♀, same locality and collector, but ex ovo, imago V.2017, slides AV3377 ♂, 3378 ♀ Volynkin (Colls AFM, ASV).

Etymology. The species name is dedicated to Dr. Thomas J. Witt (Munich, Germany), a famous lepidopterist, a founder of the Museum Witt Munich having one of the largest collections of Heterocera in the world.

Diagnosis. Externally, L. witti sp. nov. is very similar to L. kozlovi and L. goergneri , but can be differentiated from L. kozlovi by its larger size, the more blackish wing coloration, the larger light costal stroke, and the slightly darker, pale yellowish longitudinal stroke along the vein 1A, and from L. goergneri by its more blackish wing coloration. The male genitalia are surprisingly different from those of L. goergneri and similar to those of L. hoenei , from which they differ by the basally narrower uncus, slightly broader tegumen, apically narrower apical dorsal process of the valva, slightly shorter ventral process of the valva, and narrower basal section of the vesica. The female genitalia of L. witti sp. nov. differ from that of L. hoenei by the slightly longer androconial glands, the broader and more heavily sclerotized antevaginal plate, the posteriorly broader sclerotized section of the ductus bursae, and the presence of three signa in the corpus bursae (while in L. hoenei there is only one signum); compared to L. kozlovi , in L. witti sp. nov. the antevaginal plate is broader, more strongly sclerotized with larger lateral lobes, the ostium bursae is narrower, the ductus bursae is slightly broader, its anterior sclerotized section is significantly longer and, on the contrary, the posterior membranous section of the ductus bursae is significantly shorter, the corpus bursae is more strongly sclerotized posteriorly, and has two signa anteriorly; compared to L. yalbulum , in L. witti sp. nov. the antevaginal plate is much broader, more strongly sclerotized, and has lateral lobes, the pheromone glands are much smaller, the corpus bursae is more weakly sclerotized posteriorly, and has two signa anteriorly.

Description. Adult ( Figs. 3–8 ). Forewing length 12–13mm in males and 10.5–12.5 mm in females. Male antennae bipectinate, female antennae ciliate. Forewing ground color from dark brown to blackish brown, pattern is creamy yellowish or slightly pinkish, consisting of longitudinal strip, longitudinal costal stroke which often subdivided into two spots, short subapical transverse stroke from costa to anterior corner of cell, and Y-shaped large postmedial spot with irregularly dentate margins; sometimes additional thin longitudinal stroke on vein 2A present; shape and size of pattern elements rather variable individually; cilia dark brown with whitish suffusion opposite cell and at anal wing margin. Hindwing ground color pale yellow, pattern dark brown to blackish brown, consisting of broad discal spot connected to broad dark area with strongly dentate margin at base and anal wing margin, and dark band in submarginal and marginal areas; cilia pale whitish, with admixture of dark brown scales between veins Rs and M1, and M2 and M3.

Male genitalia ( Figs. 22, 23 ). Uncus dorso-ventrally flattened, medium-broad, trigonal, slightly broadened medially; tegumen heavily sclerotized, very broad, with curved margins; tuba analis narrow, membranous; vinculum broad, more or less U-shaped; valva narrow, elongated, with almost parallel margins; apical dorsal process of valva short, apically tapered, projected distally-dorsally; ventral process of valva situated apically and projected distally; aedeagus long and narrow, slightly S-like curved; aedeagus carina long and narrow, band-like, moderately sclerotized; vesica broad, curved dorsally, consists of two sections: the broad basal one having weak spinulose scobination distally, and the distal one which is narrower, and has a small scobinated diverticulum basally, a cluster of granulation medially, and a broad apical diverticulum having strong spinulose scobination.

Female genitalia ( Fig. 29 ). Ovipositor short, almost quadrangular; papillae anales broad, rectangular, with rounded angles; apophyses posteriores long and narrow; apophyses anteriores narrow, much shorter than apophyses posteriores; ventral pheromone glands narrow, very long; antevaginal plate short and broad, with short trigonal lateral lobes, moderately sclerotized; ostium bursae medium-broad; ductus bursae long, dorso-ventrally flattened, heavily sclerotized, its posterior end at ostium bursae membranous; corpus bursae sack-like, its posterior section weakly rugose sclerotized, anterior section with two small signa; appendix bursae large, broadly conical, weakly rugose sclerotized, situated latero-posteriorly; bulla present, large, broad, sack-like, membranous.

Biology and bionomics. A single female ( Fig. 8 ) was collected in a Coleoptera ground trap in May, 2016 in a remote part of the southwestern part of China’s Sichuan Province, near Daocheng. Lithosarctia kozlovi was collected at an altitude approximating 4100 meters in mountain mixed forests dominated by various conifer trees, bushes and rhododendron ( Fig. 39 ). Imagoes there were not attracted to lights.

Larvae in the 1 st instar ( Fig. 33 ) are 1–1.5 mm in length, feed on the egg chorion directly after hatching, and start feeding on leaves in a day. Larvae are nocturnal, and in the 1st–2rd instars feed on only wilted leaves but from 4th instars larvae prefer both fresh and wilted; in the 1st–2rd instar they gnaw through the inner parts of leaves, the latest stages larvae feed whole leaves from the edges. Larvae are probably polyphagous and fed on the leaves of lettuce ( Lactuca sativa ), a common plant species for the breeding of European Arctiini under artificial conditions. Larvae in the 4th instar ( Fig. 34 ) measure 22–25 mm. After the last exuviation, larvae ( Figs. 35, 36 ) did not feed for 24–36 hours, and after that actively crawl some distance before settling down to pupate. Pupation occurs in a weak cocoon ( Fig. 37 ) in plant litter. The pupa ( Fig. 38 ) overwinters.

Under artificial conditions, the caterpillars were kept at room temperature and natural lighting, the pupation lasted from 18 to 24 June; the pupae were kept at room temperature till 25 September and later moved into a fridge with the temperature 2 °C for overwintering. From 20 March of the next year the pupae were moved outdoors with the lowest minus 5 °C temperature. The imagoes hatched from 8 to 22 May when temperature was 8–10 °C.

Distribution. China: Sichuan ( Fig. 40 ) and eastern Xizang.

Figures

FIGURE 39. China, W Sichuan, Shaluli Shan, 40 km NW from Daocheng, H-4060 m, N 29°17.401’ E 100°05.068, the habitat of Lithosarctia witti (photo by A. Saldaitis).

FIGURE 40. Distribution map of the species of Lithosarctia.

FIGURES 1–10. Lithosarctia spp., adults. 1, L. hoenei, paralectotype ♂, China, Yunnan (MWM/ZSM); 2, L. hoenei, ♀, China, Yunnan (©NHMUK); 3, L. witti, holotype ♂, China, E Xizang (MWM/ZSM); 4, L. witti, paratype ♂, China, Sichuan, ex ovo (ASV); 5, L. witti, paratype ♂, China, Sichuan, ex ovo (ASV); 6, L. witti, paratype ♀, China, Sichuan, ex ovo (ASV); 7, L. witti, paratype ♀, China, Sichuan, ex ovo (ASV); 8, L. witti, paratype ♀, China, Sichuan, collected in nature (ASV); 9, L. kozlovi, holotype ♀, China, Sichuan (ZISP; photo by A. Matov); 10, L. y-albulum, holotype ♀, China, Tibet (©NHMUK).

FIGURES 21–24. Lithosarctia spp., male genitalia. 21, L. hoenei, paralectotype, China, Yunnan, slide MWM 33707 Volynkin; 22, L. witti, holotype, China, Xizang, slide MWM 33701 Volynkin; 23, L. witti, paratype, China, Sichuan, slide AV3377 Volynkin; 24, L. y-albulum, China, Sichuan slide MWM 33706 Volynkin.

FIGURES 28–32. Lithosarctia spp., female genitalia. 28, L. hoenei, China, Yunnan, slide BMNH(E) Arct-6147 László (©NHMUK); 29, L. witti, paratype, China, Sichuan, slide AV3378 Volynkin; 30, L. kozlovi, holotype, antevaginal plate below, slide Matov 0538 (photo by A. Matov); 31, L. y-albulum, holotype, China, Tibet, slide BMNH(E) Arct-6149 László (©NHMUK); 32, L. y-albulum, China, Sichuan, slide MWM 33705 Volynkin.

FIGURES 33–38. Lithosarctia witti, preimaginal stages. 33, larva in the 1 st instar; 34, larva in the 4 th instar; 35, larva in the 5 th instar; 36, larva in the 5 th instar with the scalebar; 37, pupa in a cocoon; 38, pupa.