Short Communication

Abstract: Elcysma, a small genus of zygaenid moths occurring in Nagaland, western China and Japan is recorded from Arunachal Pradesh, northeastern India for the first time. The other known species from northeastern India is E. dohertyi, so far known only from Nagaland by a single specimen collected by W. Doherty in 1889. A new species, E. ziroensis is hereby described. The other species of the genus is white in colour with prominent black veins whereas the new species has very broad black stripes along both sides of the veins taking over the white background on forewing and brown background on hindwing, making the moth look entirely blackish in colour. The new species also has the orange patch restricted to the upper base of forewing, whereas the other species of the genus has orange patch in whole of base of the forewing. The shape of the wing resembles that of E. dohertyi in being narrower forewing and hind wing. The wing venations is, however, markedly different from all other Elcysma species having five radius veins with three posterior radius sectors branching out to the apical area in forewing. The species also shows mimetic assemblage with B. lidderdalii which also flies together at the same locality.

Keywords: Arunachal Pradesh, Elcysma ziroensis sp. nov., Lepidoptera, northeastern India, Ziro, Zygaenidae.

During a field trip to Talle Wildlife Sanctuary we colleted by a very torn deformed moth found to be an undescribed female Elcysma, at an elevation of 1,700m in Ziro, Arunachal Pradesh. This discovery represents the first record of Elcysma from Arunachal Pradesh, northeastern India. We describe this new species based on its morphological features particularly its wing patterns and venation which are markedly different from the other three species of the same genus. Details of the life history were not recorded. Pictures of a female, however, were taken seemingly laying eggs on a branch of a species of Prunus of the Rosaceae family.

The genus Elcysma was established by Butler (1881) being a small genus of three known species so far, viz., E. delavayi Oberthür, 1891 (western China), E. dohertyi Elwes, 1890 (Nagaland, India), and E. westwoodii (Snellen van Vollenhoven, 1863) (Japan; Yen et al. 2005); type species E. translucida Butler, 1881 of Yokohama, Japan (Butler, 1881), synonyms: E. westwoodii (Snellen van Vollenhoven, 1863); Elcysma westwoodi (Snellen van Vollenhoven, 1863); synonyms: E. caudata Bremer, 1864 and E. eleganticauda Bryk, 1948; belonging to the subfamily Chalcosiinae, tribe Aglaopini of the Zygaenidae family. All taxa are large and brightly coloured diurnal moths, tailed at the medial veins at the hindwing. The life history of E. westwoodii is well documented in Japan. All the three species have a yellow/orange patch edged with a dark line at the edge of forewing including the specimen of E. dohertyi Elwes, 1890 occurring in Nagaland, but the new species has an orange patch restricted to the upper base of forewing. Also, the venation pattern of the species was different and distinct from the other species of the genus but supports allocation to the genus (Yen et al. 2005).

Notes on Elcysma species

1. Elcysma delavayi: The species has a broad orange patch edged with a dark line at the edge of forewing base (Image 2). Its adult and larval stages have been documented by Yen et al. (2005).

Distribution: The species occurs in western China.

2. Elcysma westwoodii: The second discocellular vein of the hindwing V6 some distance from the end of the cell (Image 3). The species has a yellow patch edged with a dark line at the edge of forewing base. E. westwoodii has three subcells in the forewing while the others have only two.

The photograph of musem specimen of the species is available at Siberian Zoological Museum (http://szmn.sbras.ru/picts/Heterocera/Zygaenidae/Elcysma_westwoodi.htm) and at Fauna and flora of wiki (http://fauna-and-flora.wikia.com/wiki/Elcysma_westwoodi). Its larval and adult stages are well documented in Japan.

Distribution: The species occurs in western Japan, Primorskii Krai (Russia) and China and is common and widely distributed in comparison to other species of this group.

3. Elcysma dohertyi: The species is allied to Elcysma westwoodii occuring in Japan. The species has a narrow yellow patch edged with a dark line at the edge of forewing base (Image 4b). The forewing is smokey, second discocellular vein of the hindwing V6 is forked close to, instead of some distance from, the end of the cell. Expanse of forewing 66mm, length of hindwing 41mm, length of antenna 12mm. The recurrent vein in the cell of forewing is simple, and not forked. Costal vein of hindwing is forked near the base, the two branches being connected by a short transverse vein near the middle of the cell. The picture of the museum specimen is available in Yen et al. (2005) and Fauna and flora of wiki (http://fauna-and-flora.wikia.com/wiki/Elcysma_dohertyi). The illustration of the species is also available in Elwes (1890).

Distribution: The only known record of the species is by W. Doherty from Nagaland, India at 1,542m in August, 1889 (Image 4a,b).

Elcysma ziroensis sp. nov.

(Images 1, 5A-5F, 7A,7B; Fig. 1D)

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Holotype: BNHS 25/2017, female, 19.ix.2016, Talle Wildlife Sanctuary, Ziro, Arunachal Pradesh, northeastern India, coll. James J. Young.

Diagnosis: The species differs in colour pattern considerably from other species of the genus. The other species of the genus are bright and white in colour and black veins being very prominently seen. The new species has very broad black stripes running along both sides of the vein almost taking over the white background on forewing and brown background on hindwing. The shape of the wing resembles that of E. dohertyi and is unlike the other two species, which have broader forewings and hindwing. The wing venations, however, are markedly different from all other Elcysma species having five radial veins with three posterior radius sectors branching out to the apical area. The other three Elcysma species have four radial branches instead, as depicted (Fig. 1). The only radial vein in the hind wing, which is unbranched, extends to the costal area unlike the other three species, where it branches out to the termen and tornal area.

Distribution: Talle Valley, western Arunachal Pradesh.

Description

Forewing (Image 1): Wingspan 7.0cm. Length of wing from base to apex is 3.5cm. Elongated forewing narrower at apex contracting convexly but becoming broader at tornus; smoky creamy white base colour; not semi translucent; a reddish dotted margin at the base of the forewing enclosed by black convexly from the costa to dorsal at the basal area; a roll of black convex splashes running from the post basal to the dorsal area; stripes of grey black markings bordered the entire wing venations almost in entirety from the discal area to the termen. Two subcells having five radius veins with three posterior radius sectors branching out to the apical area; four media veins running from the cells; cubitus with one main branch and two unbranched anal veins; veins raised in black; underside of wing resembling the upper surface (Image 5).

Hindwing (Image 1): Hindwing narrow extending into a long tail supported by media veins; partially covered with stripes of grey blacks bordered the wing veins almost from half-way to the tail; humeral and subcosta veins missing with only one radial vein branching out to the costal area; four media veins branching out from the two subcells with M2 and M3 extending to the end of the tail; the cubitus with two anterior branches arising from the subcell 2; other two anal veins branching out from the base; frenulum with two filaments arising from the hindwing; underside of wing resembling the upper surface but lighter in colour (Image 5).

Head: Image 5a. Length of antennae 11.4mm. Black bipectinate antennae with scales at pedicel and scape; naked at shaft; head black with shine; non-hairy only posterior to eye clothed with dark brown hairs, eye round without minute hair; black grey scales covering frontoclypeus and labial palpus; labial palpus reduced and non-porrected; proboscis unscaled; a pair of dome-shaped chaetosemata (Eltringham’s organs) at dorsal to eye; thorax and abdomen black.

Genitalia: The genitalia of this female individual was damaged. Partially, the specimen revealed extended ovipositor as depicted in Image 1 & Image 6d.

Etymology: The name of the species is derived from the type locality Ziro, Arunachal Pradesh in northeastern India.

Suggested common name: Apatani Glory is given as the English common name based on the tribal people living in Ziro.

Permit: Permission obtained by the Government of Arunachal Pradesh, Office of the Principal Chief Conservator of Forests (Wildlife and Biodiversity) Itanagar with no. CWL/G/13(95)/2011-12/Pt.I/2362-63 dated 02 November 2016.

Discussion and Conclusion

This is a brightly coloured diurnal species with a slow and fluttering flight. Its flight period matches with Bhutanitis lidderdalii Atkinson, 1873 with similar wing patterns, which are seen flying at the same time in the same locality. Both are fairly common in Talle Wildlife Sanctuary in Ziro. As zygaenid moths are chemically protected and aposematic (Naumann et al. 1999) and B. lidderdalii feeds on Aristolochiaceae rendering them unpalatable to predators, there appears to be a co-mimetic assemblage of the two species. A possible male individual was photographed (Image 6b) drinking at puddles on 17/IX/2010. This species does not appear to exhibit strong sexual dimorphism in wing pattern and size though the possible male appears to show a much darker ground colour and conspicuous markings than the female. The details of life history are unknown. Pictures of a female laying egg were taken on 18/IX/2016 and two photographs are depicted in Image 7a,b. From observations, this species has only been seen during autumn, notably in the month of September indicating that it is a univoltine species. This coincides with the laying of eggs in September. It is expected that the eggs will hatch in a few days and the larvae will hibernate in cracks in the trees where they are placed to survive during the cold winter at this high elevation of 1,700m in Ziro. The larvae will become active and feeding after diapause in the spring when new foliage appears. The final instar larvae will pupate in August and adults will appear again in September. This taxon appears to share a similar life history with E. westwoodii (Owada, 1992). The host plant appears to be a species of Prunus, Rosaceae family.

REFERENCES

Butler, A.G. (1881). Elcysma translucida. Transactions of the Entomological Society of London 29: 4.

Elwes, H.J. (1890). On some new moths of India. Proceedings of the Zoological Society of London 1890: 378–401, pls. 32–34.

Naumann, C.M., G.M. Tarmann & W.G. Tremewan (1999). The Western Palaearctic Zygaenidae (Lepidoptera). Apollo Books, Stenstrup, Denmark, 304pp.

Owada, M. (1992). The chalcosiine moths of Agalope (Lepidoptera, Zygaenidae) from Taiwan, with notes on allied genera. Japanese Journal of Entomology 60(1): 85–95. 

Yen, S.H., G.S. Robinson & D.L.J. Quicke (2005). The phylogenetic relationships of Chalcosiinae (Lepidoptera, Zygaenoidea, Zygaenidae). Zoological Journal of the Linnean Society 143: 161–341.