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za t deSk Trans. Iepid. Soc. Japan 55 (3): 203-208, June 2004

A new subspecies of Hestina nicevitlei (Moore, 1896) (Lepidoptera, Nymphalidae) discovered in Northern Vietnam

Keiichi OMoToi) and Akio FuNAHAsHi2)

') 4-1-18-610 Hiroo, Shibuya-Ku, Tokyo, 150-OOI2 Japan, 2' 4-18-33-1Ol, Kajinocho, Koganei-Shi, Tokyo, t84-OO02 Japan.

Abstract A species of the Apatulinae, Hestina nicevillei (Moore, 1896) was recently found in Hh- Giang, Northern Vietnam, and we here describe it as a new subspecies: Hestina nicevillei magna. It is also the first record of sympatry of the species with the allied species H. assimilis (Linnaeus, 1758). This subspecies is clearly distinguishable from other subspecies by its large size and much

rcduccd black markings on thc upperside of both wings, as wcll as a tiny, fuint red submarginal

spot on the hindwing reminiscent of the characteristic red markings of H. asb'imilis. It is known that H. nicevillei represents a cLassic case of Batesian mimicry, since the coler pattern in all the subspeeies hitherto known is remarkably similar to the local forms of Aporia agathon (Gray, 1831), which is considered to be offensive for birds. It is puzzling, however, that this medel pierid species has thus far not been found in the area around Hb-Giang, although a large nurnber ef butterflies havc been cQIIected. On the other hand, i`iporia giganthea Koiwaya, 1993, which is commen there in spring, tooks somewhat simiLar to ssp. magna in size and coloration. Furthcrmore, the white seasonal form of Hlestina assimitis is also common, whJch at the first giance is a]most indistinguishable from ssp. magna both in size and color pattcm. Some possibilities regarding the origins ef the unique features of H. nicevillei magna are discussed with special reforence to the phenomena of mimicry and convergence.

Key "'ords Nympalidae, Apatulinac, Hestina nicevillei, Hestina assimitis, Aporia agathon, Aporia giganthea, Batesian mimicry, Northern Vietnam.

Introduction

Recently, a number of new or little known taxa of butterflies have been recorded from Northern Vietnam (Shinkaj, 1999; Funahashi, 2003). In particular, many species hitherto known mainly from China were reported from Hh-Giang (=Ha-Jiang), Hb-Giang Province, in the northernmost part ef Vietnam near the border with YUnnan Province of China. They include Aporia giganthea Koiwaya, 1993, Sasakia charonda (Hewitson, 1863), S. junebris (Leech, 1891), Helc)Jiu superba Leech, 1890, H. subalba (Poajade, 1863), Hestina assinzitis (Linnaeus, 1758) and others, Tb add to this list, we here report the discovery of a rare nymphalid butterfiy of the subfamily Apaturinae, Hestina nicevillei (Moore, 1896) from Hza- Giang, which we consider to be a new subspecies with a nuinber of unique characteristics.

This species has hitherto been known from Northem India, Nepal, Tibet and Southwestern China, and three subspecies have been described in addition to the nominotypical form

occurring in Northwestern Himalaya and Western Nepal. Each subspecies with its characterigtic color pattern exactly matches the local form of Aporia agathon (Gray, l831), known to be an ofiensive butterfly for birds, indicating a classic example of Batesian mimicry (Morishita, 1997). It is, however, puzzling that this pierid species has thus far not been found around Hti-Giang. On the other hand, another Aporia species, A. giganthea Koiwaya, 1993, is common in Hh-Giang, and looks somewhat similar to a new subspecies of H, nicevillei below described as magna both in size and color pattem, Moreover, the new subspecies bears a striking resemblance to the white form of the allied species H,

assimilis, f, mena, which is also very common in the area. The distribution of these two

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204 Keiichi OMoTo and Akio FuNAHAsH[

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Fig 1 Photographs of Hestina nicevillet magna ggp nov (a holotype, r, upperside b ditto, underside L di" paratype, upperside d ditte, underside e a photograph of the enlarged part of hmdwrng showing a tmy, famt red spot mdicated by dn arrow )

Hestina species as hitherto known has been al]opatnc, and the present report proyides the first evidence of their sympatry

At present, it is not known whether the umque characteristics of H nicevillei magna, particularly its large gize and whitish appearance, arose as the result of Batesian mimicry with A agathon which has not yet been found, or of other processes such as convergence with H asstmiks (f mena) Alse, it remarns unknewn whether A giganthea plays the role of mimetic model similar to that of A agathon in other locahtieg There ig however a problem with both theones, since both A giganthea and H asgimilis, f mena fly mainly in sprmg (March to May), while the gpecimens of H mcevillet magna were collected in summer (June to August)

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205 A New Subspeues of Heytina nieevillei trom Vtet]am

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Fig 2 Photographs of llegtina asgtmilis, f mena (a upperside b underside), and Apona gtganthea (L upperside, d underside)

Hestina nicevillei magna ssp. nov. (Figg l a-e)

8 Size much 1arger than the known subspecies, fbrewing length 48 mm, ag contrasted to 39-41 mm of other subspecies Black area much reduced both on the forewing and the hmdwmg, the upperside being almost mdistinguishable at the first glance from H assimttis, f mena (see Figs 1 and 2) On the underside, however, it is readily distanguished from H assimilis by two conspicuous yellow areas, one at bage and the other at mner margm of the hmdwing A tsny, faint red touch ig ebservable in the space between veins 2 (CuA,) and 3 (CuA,) at the subcostal area of the hmdwmg, remmiscent of the red spots pregent in Hestina assimihs, indicat]ng a cloge relationship of the two species (Fig le) Also, the basal contour ot the outer margin of the hmdwmg of H nicevdlei ig dilferent from that of H assimiliy Thug, in the latter species, it is not smoothly round as m the former with a slight inward excision Although this excision appears to be present in the paratype specimen (Figs lc, d), it is probably due to an accidental defbrmation of this individual Also, the color pattern is slightly different between the two specimens, the paratype specimen haymg the black markmg more reduced than that of the holotype (Figs la, b)

? Unlmown

Holotype (Figs la, b) 8, Hb-Giang (on the way to D6n Van), alt 2,OOO m, Northern Vletnam, June 2003 (local collector leg) Paratype (Figs lc, d) 18,same locahty, Aug 2003 (local collector leg ) The type specimens are temporality preserved in K Omoto's collectson until finally lodged m the National Science Museum, Tbkyo

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206 Keiichi OMoTo and Akio FuNAiiAsH]

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Fig. 3. Map showing the distribution of Hestina nicevillei and H. assimilis (adapted from Masui and lnomata (1997) with modifications).

Discussion

Hestina nicevillei is a rare species of the subfamily Apaturinae (Lepidoptera, Nymphalidae). Thus far, four subspecies have been known as listed below (Masui and Inomata, 1997; Morishita, 1997).

Ssp. niceviltei (Moore, 1896): NW Himalayas (Chumba-Kunjiar); W Nepal, Ssp. J'eipm,ni (Druce, 19 1 1): [[bns Viilley, N India (Uttur-Pradesh), Ssp, ouvranti (Watkins, 1928): NW Yi]nnan; SE Tibet, China, Ssp, nigra Morishita, 1997: Kathmandu Valley, C Nepal.

The present paper describes a fifth subspecies, magna ssp. nov., providing also a new record of the species from Vietnam as well as the first evidence for sympatry with its allied species H. assimitis (Fig. 3).

As described above, this new subspecies has severa] unique features and is readily distinguishable from al1 the known subspecies. It is the largest among the known subspecies, the forewing length of two male specimens (holo- and paratypes) being 48 mm. The forewing lengths of other subspecies measured by us (exeept ssp. nicevillei measured by Mr Kazuhiko Morishita) are as follows. Al] are male specimens, and the numbers in parentheses are the sample size. Ssp. niceviUei (1): 39 mm. Ssp. ouvvandi (5): 40-41 mm. Ssp, nigra (5): 39-40 mm. We were not able to measure tlte type specimen of ssp.jermyni preserved in Natural History Museum, London. This remarkable subspecies almost lacks the black marking, being more whitish than ssp. magna, The original description by "expanse" Hamilton H. Druce gives the data of the of 92 mm. According to Evance (1932), the expanse in the old British measurement system is not simply the distance between the "obtained apex of both wings in the expanded state, but by measuring from the centre of the thorax (the pin) to the tip of the forewing and doubling the result" (Evans, 1932: 12).

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207 ANew Subspecies of Hestina nicevitlei from Vietnam

Following to this system of measurement, the length of the forewing of ssp. jernzyni must be much smaller than the 48 mm of ssp. magna, The type specimen illustrated in "Buttenyzfiies D'Abrera's book oj' the Abla,z:tic Region, Part III" (p. 377) indicates the fbrewing length as approximately 40 mm.

The important question is as to the origin of the large size and the unique color pattern of ssp. magna. All the known subspecies show striking similarities to those of the loca] forms ofA. agathon. According to Morishita (1997), citing a personal communication of Haruo Kimura, this species is considered to be oflbnsive for birds due to the poisonous substance derived from the larval food-plant of the genus Berberis, Thus, the co]or pattern of H. nicevillei with A. agathon as a model is considered to be a classic examp]e of Batesian rnimicry (Morishita, 1997),

We are puzzled, however, since this model pierid species has not been found around Hh- Giang, although quite a large number of butterflies has been collected, It occurs in Sapa, Ltio Cai Procinve, about 100 km to the west of Hh-Giang on the opposite side of the River Hong. One of us (A, F.) has been both in Ha-Giang and Sapa, and finds that two habitats are markedly ditlerent in terms of biotepe and fauna. Described as A. agathon sapaensis by Funahashi (2003), its coloration does not match that of H. nicevillei magna.

On the other hand, another species of the genus Aporia. A. giganthea, is common in Hh- Giang. With its large size and ,whitish coloration, it looks somewhat similar to ssp. inagna (Figs 2c, d). It is not known whether A. giganthea represents an oflensive species for birds lilre A. agathon, but one may speculate that this is the case for most Aporia species. One of the unique features of H. nicevillei, tmd not of H, assimilis, is a bright yellow spot at the base of hindwing underside, which is an important marking shared with the Aporia species.

The situation seems to be more comlex, sjnce H. assimilis is very common in Het-Giang, and the white form (f, mena) is almost indistinguishable at the first glance from H. niceviUei magna (Figs 2a, b). Altheugh the former lacks the basal yellow spot on the hindwing underside, both look very similar in size and color pattern, raising a questiQn on the mechanism of Batesian mimicry, It is known that the color pattern of H. assimitis exhibits a remarkable variation. The white form, f. mena, is regarded as a seasonal form, but genetic factors may play a role in addition to the environmental factors like temperature and humidity, Thus, in Hong Kong, it is observed in spring (March to May) together with the usual fbrm and a variety of intermediate fOrms (Wakabayashi, 1992). In Hh-Giang, Northern Vietnam, specimens of f, mena are collected mostly in April, while it is also taken in June at relatively high altitude, together with the usual form as well as al1 possible gradations of intermediate forms.

It is tempting to speculate that, at least in this particu]ar area, the unique features ef H. nicevittei magna arose as a result of conyergence to H. assimitis, rather than the mimicry. It is notable that this area around Ha-Jian of Northern Vietnam is unique in that both H, nicevillei and H. assimilis occur together (Fig. 3). The finding that ssp. magna shows a tiny red spot on the hindwing indicates that H. nicevillei and H, assimitis are in fact closely related to each other, as suggested by Morishita (1997).

Future field studies are needed to answer the question on the origins of the unique features of H, niceviUei magna. Firstly, jt is important to find out whether A. agathon in fact occurs somewhere in the area around Hh-Giang. It is tempting to speculate that, if it is found, it will prove to be as 1arge and whitish as in H. nicevillei magna and H, assimilis, f. mena, which would provide a pointer to understanding the ecological relationship between them,

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208 Keiichi OMoTo and Akio FuNrxHAsHi

Acknow 亘edgments

We thank Mr Kazuhiko Morishita and Mr Akio Masui for their invaluable advice and comments on this papeL

References ’ D Ahrer 乱， B ，，1993 ． ButtefLtlies Of the Hola rctic Region ， Palt IIL Hill House ， Victoria， Australia． Druce， H ． H ．，1911． Description of a new Nympha ユine butterfly from British India． T 厂ans ． ent ． Soc． Lond． − 1911： 187 188 ，pL 29． Evans ， W ． H ．，1932 ， Identipcatton of the lndian Butteij7ies（2nd Edn ）． Bombay ．

− Funahashi， A ．，2003． Butterflies of Vietnam， part 2， WallaceS ： 3 17． Masui， A ． and T． Inomata，1997， Apaturinae of the world （Leptidoptera， Nymphalidae）8． Yadoriga （170 ）： − 7 23 （in Japanese）． Morishita K 1997 Hestina a ∬ imitis and allies Nyamphalidae Buttenyflies ： − ， ．， ． its （ ；Apatulinae）． （16）34 44 （in Japanese with English suユ皿mary ）． ： − Shinkai，A ．，1999．Butterfliesof Vietnam， partL Waltace6 45 65． − ’ Wakabayashi ， M ．，1992 ． A white form of Hong Kong s Hestina a ∬ imitis（Linnaeus，1758）． Butterjlies（1）： − 44 49 （lnJapallese with English summary ），

摘 要

ベ トナ ム 産 ニ セ ビ ユ ゴ マ ダ ラ の 1 新 亜 種 （尾 本 惠市 ・舟 橋 彰 男）

コ ム ラサ キ 亜 科 の 珍種 ニ セ ビ ユ ゴ マ ダ ラ は ，従来 ヒ マ ラ ヤ 南部 か ら中 国 西 部 の 地域 よ り知 られ て い

ベ ム − ゴ マ た が ，最近 ， トナ 北 部 の Hb Giang市 付近 で オ ス 2 頭 が発 見 され た．ア カ ホ シ ダ ラ と 同所 的 に る こ と は で る ． の の 亜 と は る の で こ こ に 亜 産す 初 記 録 あ 比 較 結果 ， 既 知 4 種 明 瞭 に 区別 さ れ ， 新 種 Hestina nicevillei magna と し て 記 載す る ，主 な 特徴 は ，著 し く大 型 （前翅 長 48 mm ；他 の 亜 種 で は 41 一 以 f）で 濠 面 の 黔 部 が 大 幅 に縮 小 し て い る こ と ，さ らに 後翅 夕櫞 部 に 個 の ご く1妝小 赫 斑 が 認 め られ る こ と で あ る ．本種 は ，同所 的 に 産 す る ゴ マ ダ ラ シ ロ チ ョ ウ （Aporia agathon ）と斑紋 が 酉告 ．こ こ ベ ー 似 す る の とは ， 後者が 有毒 物質 に よ っ て 鳥 に 忌 避 され る と考 え られ る た め ， ッ 式擬 態 の 好 例 と さ れ る （Morishita，1997）．し か し ，今 回 の 発 見 地 で は ゴ マ ダ ラ シ ロ チ ョ ウ は 発 見 さ れ ず，同属 で は − Pk A ． giganthea を産 する の み で あ る ．こ の 種 は ，大型か つ 黒色部が 少 な い 点 で 亜 種 magna と や や 類 一 似す る た め ，擬態 の モ デ ル と して の 可 能性 が な い とは い えな い ． 方，亜 種 magna は，同所 的 に多産 す

ゴ マ f mena ニ セ ビ ユ ゴ マ る ア カホ シ ダ ラ の 白化型 （． ）と形態 的 に 酷似 す る ．た だ し， ダ ラ は後翅外縁 の

輪郭 の 相違 に加 え て ，後翅 裏面 基 部 お よ び 内縁 部 に鮮 や か な 黄色紋 が 存在 す る こ と に よ っ て ア カ ホ シ ゴ マ ダ ラ と 区 別 され る ，亜 種 magna の 後翅 に 痕 跡 的赤斑 が 認 め られ る点 は，本 種 で は初 の 例 で ，ア

カ ホ シ ゴ マ ダラ と の 系統 的近縁性 を物語 る ，今 後 の 調査 に よ っ て 同 地か ら ゴ マ ダ ラ シ ロ チ ョ ウ が発 見 され れ ば ，そ れ は大 型 で 白色 部が 拡 大 した形 態 を も つ こ とが 予 想 さ れ る ，しか し，も し発見 され な

い に は 亜 magna の に と っ て 上 の 2 の の モ ル A ． い 場合 ， 種 斑紋 形成 ’ 述 種 蝶 が ，擬 態 デ （ giganthea）な し収 ゴ マ こ 斂現 象 （ア カ ホ シ ダ ラ ）な ど の 可 能性 を含 め ， 何 らか の 役 割 を演 じた と も推定 され る ． の 仮説 に 対す る 問題点 は ，こ れ ら 両者 が春 （3−5 月 ）に 出現 す る の に，亜Pt magna は 夏 （6−8 月 ） に採集 され た こ − とで あ る ．しか し，HtiGiang付 近 の 比 較 的 高 地 で は f， mena が 6月 に も採集 され て い る の で ，両者 が 無 関係 と は 言 い 切 れ な い ．亜種 magna の 特異 な形 態 の 起源 と い う興 味 あ る 課題 を解 決す る た め に は ，野 外調査 に よる生 態観 察が 必要 で あ る．

（Accepted April 12，2004 ）

hblished by the Lepidopterological Society of Japan， − − 5 20，Motoyokoy a 2， Hachioji， Tokyo ，192 0063 Japan

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