Thitarodes shambalaensis, Wang, Zhengyang, Zhuang, Hailing, Wang, Min & Pierce, Naomi E., 2019

Wang, Zhengyang, Zhuang, Hailing, Wang, Min & Pierce, Naomi E., 2019, Thitarodes shambalaensis sp. nov. (Lepidoptera, Hepialidae): a new host of the caterpillar fungus Ophiocordyceps sinensis supported by genome-wide SNP data, ZooKeys 885, pp. 89-113 : 89

Thitarodes shambalaensis sp. nov. Figs 1 , 2 , 3 , 4 , 5

Type material.

Holotype: CHINA • ♂; Mt. Gongga, Luding county, at the head of Yanzigou valley (燕子沟), Yangliuping habitat (杨柳坪); 29°41'2.54"N, 101°53'32.24"E; alt. 3892 m; 25-30 Jun. 2016; H. Zuo leg.; MK226958; Sichuan Plant Quarantine Station.

Paratypes: CHINA • 2 ♂; same collection data as for holotype • 2 ♂; Mt. Gongga, Luding county, at the head of Yanzigou valley (燕子沟), Haizidang habitat (海子凼); 29°40'17.18"N, 101°53'48.25"E; alt. 3977 m; 25-30 Jun. 2016; H. Zuo leg. • 2 ♀; same collection data as for holotype.

Etymology.

From the Sanskrit word शम ्भल (Shambala). In Hindu and Tibetan Buddhist tradition, the term refers to a mythical kingdom hidden in the snow mountains. The name refers to the magnificence of the species’ alpine habitat under Mt. Gongga.

Description

(based on Holotype). General. In resting position, forewings fold perpendicular above the sagittal plane of the body and abdomen, completely covering the hindwings. The apex and termen of the two forewings contact each other, while the costa of each forewing extends from the tegula, forming an isosceles. Setae above the thorax form a triangular patch. Wingspan: 44.0 mm (mean = 41.2 mm, SD = 3.5, N = 6). Forewing length: 19.6 mm (mean = 19.2 mm, SD = 1.6, N = 6), width: 9.9 mm (mean = 9.9 mm, SD = 0.6, N = 6). Hindwing length: 16.9 mm (mean = 16.5 mm, SD = 0.8, N = 6), width: 12.25 mm (mean = 11.7 mm, SD = 0.9, N = 6). Body length: 15.3 mm (mean = 14.7 mm, SD = 1.1, N = 6). Thorax width: 3.7 mm (mean = 3.6 mm, SD = 0.2, N = 6).

Head. Antenna ( Fig. 3B ) with 24 annular segments, rust brown, filiform, apical segment acute, surrounded by ocherous setae at base. Black compound eyes. Labial palps ( Fig. 3C ) short and hidden under dense setae, two-segmented and fused at the base. Other mouthparts absent.

Body. Red-brown. Dense ocherous and yellow setae on thorax. Red and black setae on lateral, ventral and caudal side of the abdomen.

Legs. Fig. 5 . All legs setose. Aerolium present on all legs. Foreleg with tibial epiphysis. Hindleg tibia broad and covered with scent-scales.

Wings. Fig. 3A . Jugum present. Forewing grey, with scattered dark brown spots and pale ocherous border. Alternating dark spots on forewing terminal margin. Costa straight. Sc unbranched. R almost parallel to Rs1 + 2. Apex of curvature occurs between Rs1 and Rs2. Rs1 and Rs2 stalked. Rs3 and Rs4 stalked. First half of Rs3 runs parallel to Rs1 + Rs2. R-M weak but visible, concave towards outer margin, reaching Rs4 distal to the bifurcation of Rs3 and Rs4. On forewing two crossveins between CuP and A with basal crossvein almost opposite CuP-CuA2 crossvein, distal crossvein near terminus of CuP. Single crossvein between CuP and CuA2. Vein A reaches dorsum margin. Hindwing grey to transparent; ocherous color on fringe. Venation similar to forewing except both A and CuP reach dorsum margin.

Male genitalia. Fig. 4 A–C . From ventral view, a pair of pseudotegumina form an equilateral triangle, with the apex of the triangle pointing ventrally. Dorsal margins of the pseudotegumina flat. Pseudotegumenal arm is strongly sclerotized, distally forming a fan-shaped sclerotized apex, with minute teeth on the lateral margin. Valvae setose, distally lobate, with a shallow longitudinal groove. Base of valve with prominent hook, heavily sclerotized, projecting disto-medially. Saccus forms a median lobe projecting ventrally.

Female genitalia (based on paratype). Fig. 4D . Dorsal plate (tergum IX) dorsally convex to either side of median, setose. Lateral margins dorsally concave with inner edge, with a triangular projection near base of anal sclerites. Anal sclerites subrectangular with rounded margins. Antevaginalis broad with central lobe subdivided into two dorsally rounded knobs, central lobe setose.

Diagnosis.

This species has no distinct external sexual dimorphism. Male pseudotegumen triangular with heavily sclerotized pseudotegumenal arms. Pseudotegumenal arms fan-shaped. Valva densely haired with sclerotized, hook-like apex. Venation of T. shambalaensis is similar to that of T. namnai Maczey, 2010 in Nepal, but in T. shambalaensis both A and CuP reach dorsum margin on the hindwing. Thitarodes markamensis (Liang, Li & Shen, 1992) has also reached the degree of heavy sclerotization on the pseudotegumenal arms, but the two species can be distinguished by differences in venation (where MR furcation in T. shambalaensis is distal to the furcation Rs3 and Rs4) and an inflation on the posterior margin of the saccus. Sclerotization at the ventral base of the valvae with a spinal projection is also present in other species of Thitarodes , such as in T. jiachaensis Zou, 2011 and T. sejilaensis Zou, 2011, but the spinal projection is less curved and the setose lobe of the dorsal side of the valvae is more elongated in T. shambalaensis .

Remarks.

With the exception of those by Ueda (2000), descriptions of Thitarodes species rarely include an illustration of the labial palp. Mouthparts are often difficult to observe and sometimes reduced (or absent) in Thitarodes , yet when illustrated, have always shown notable differences between species ( Fig. 7A ). We encourage in future description of species in Thitarodes to include an illustration of the labial palps, as it might serve as a trait useful in resolving clade relationships within the genus.

Phenology.

Late instar larvae, sometimes already infected by O. sinensis , can be found as early as mid-May, about 30 cm under soil. Pupae can be found starting early June in soil. Adults appear in a week in late June.

Ecology.

The species is found in several high elevation (3400-3800 m) alpine grassland along the glaciers of eastern Mt. Gongga ( Fig. 2 ). Larvae are ground-boring generalist plant root eaters. Common flowering plants in in the grassland include Saxifraga , Rhodiola , Polygonum , Corydalis , Primula , Potentilla and Anemone ; Salix and Rhododendron bushes are also present. Adults are not attracted by light and no mating flight has been observed.

Conservation threat.

The species is the host of O. sinensis . Caterpillar fungus collection has for decades provided income for local people in eastern Mt. Gongga. The traditional method of collection has not had a discernible impact on populations of T. shambalaensis , but since 2016, medical pharmaceutical companies have begun buying T. shambalaensis pupae from local people for a commercial caterpillar fungus farming project. Many T. shambalaensis pupae have been excavated from their habitat each year, sold and transferred to commercial breeding stations. Local people have expressed concern at such habitat exploitation. When we visited the Haizidang habitat in 2019, this alpine grassland had been completely uprooted due to pupae excavation ( Fig. 2B ).

Figures

Figure 1. Thitarodes shambalaensis sp. nov. A holotype, male, dorsal view B paratype, female, dorsal view C holotype, male, ventral view D paratype, female, dorsal view E resting position in habitat (photograph credit Hua Zhang). Scale bar: 1 cm.

Figure 2. A Natural habitat of Thitarodes shambalaensis sp. nov. at Yanzigou glacier entrance point, Mt. Gongga, Sichuan, China (photograph credit Meng Li, May 2018) B disturbed habitat of Thitarodes shambalaensis sp. nov. due to excavation of T. shambalaensis pupae, at Haizidang, Yanzigou glacier (photograph credit Wenbin Ju, May 2019).

Figure 3. Thitarodes shambalaensis sp. nov. A forewing (up) and hindwing (bottom) venation from dorsal view B antenna, front view C labial palp, caudal view, covered under setae. Scale bar: 1 mm.

Figure 4. Thitarodes shambalaensis sp. nov. A male genitalia from holotype, ventral view B valva, caudal view C pseudotegumen, lateral view D female genitalia from paratype. Scale bar: 1 mm.

Figure 5. Thitarodes shambalaensis sp. nov. Foreleg (left), midleg (middle), hindleg (right) with each aerolium enlarged in black rectangles. Scale bar: 1 mm.

Figure 7. Diagnostic characters of Thitarodes shambalaensis sp. nov. in comparison to other species of Thitarodes A labial palp B valva C pseudotegumen. Scale bar: 1 mm.