The LepidopterologicalSocietyLepidopterological Society of Japan uetma Trans. tepid. Soc. Jtipan 60 (2): 152-160, March 2009 Eilic)ets of Cleltis sinensis and euercus acutissima afforested area on a population of the near-threatened butterfly, Sasakia charonda (Lepidoptera, Nymphalidae) in central Japan rlakato KoBAyAsmi'*, Masahiko KiTAHARA') and [Ibhm NAKAsHizuKA2) `)Laborutory of Animal Ecolegy, Yamanashi Institute of Environmenta1 Sciences, 5597-1 Kcnmarubi, Kamiyoshida, Fujiyoshida, Yamanashi, 403-OO05 Japan " Graduate School of Life Sciences, Tohoku University, Aoba 6-3, Ar2tmaki, Aoba-ku, Sendai, 980- 8578 Jap an Abstract To clarify the distribution patterns of resource plants suitablc for conserving Sasakia charondl:, we investigatcd the densities and sizes ofboth 1arval host trees, Cettis sinensis, and trees which serve as an adult food resource, 2uerc/us acutissima, as well as the number of ovcrwinteritig S. charostda larvae per host trce at an area planted with a mix of C. s'inensih' and C, acutissima for preserving S. charonda and in thc surrounding area ofnutural forests. In the atlbrested area, scvcral of the C. sinensis trees planted in the center withered and died, whilc none of the 2. ac"tissima trees died. Dbh (diameter of breast height) of C. sinen.s'is at the edge of thc aff'orested area was signjficanlly 1arger than that at the intcrior, and simi]ar to tliat in the surrounding area of natural forests. In {he surruunding natural forests, dbh of C. sinensis at the edge was also significantly larg- er than that at the intcrior. The number of overwintering 1arvac was significantly smaller in thc af forcsted area than in the natural forests. In both the at:fbrested area and thc natural forests, the num- ber or overwintering larvae was significantly greater at the edge than in the interior, However, no significant dil]k]rcnces were found in lhe "umber of ovcrwintering ]arvae between thc cdge of the afforested area and in thc natural forests. For conservation of S. charonda, it is suggested thur 2. ac"tissima trees should be planted in the interLer of a planned afforestatien area and C. sinensis sheuld bc planted at the edge of the affOrestation area. Key words Sa,s'akia charonda, host trees, adult fOod resourcc, ufforestation, edges of forests, con- servatlon. Introduction [Ib conserve populations of rare organisms, especially those experiencing dramatic habitat loss, it is essential to restore the habitats with arrangements of their resources suitable for maintaining their populations. [[b do this, it is necessary to first claiify the effective arrangements of resources for conserving the populations. HQwever, few attempts have yet been made to undertake conservation activities for endangered species based on such scien- ti fic knowledge, In Japan, the giant purple emperor, Sasakia charvndti (Lepidoptera, Nymphalidae), is a symbolic insect known as the country's natienal butterfiy. At one time, the species was very common in secondary broadleaf deciduous forests and riparian forests almost all over the country. However, since Japan's period ef rapid economic growth, populations of the species have declined mostly due to deforcstation associated with changes in land use such as construction of roads and buildings, and the resultant decrease in the numbers of their host trees, Cegtis sinensis, and Cettis .iessoensis (Higuchi & Sato 1987). Consequently, S, *Cerrcspondingauthor:[email protected] Contact address: K-1O1, 2-2-18 Umezene, Tsukuba, Ibaragi, 305-O045 Japan NII-Electronic LibraryMbrary Service The LepidopterologicalSocietyLepidopterological Society of Japan 153 EtTects of afforested Area on Sasakia charonda charonda is now designated as a near-threatened insect in Japan (Ministry of the Environment 2006), and conservation efforts for the butterfly have been initiated in various localities around the country. Usual].y as part of these efforts, C. sinensis or C. jessoensis, which are host trees of the lar- 'food vue, and ettereus act{tissima, whose sap is a major resource for the adu]ts in central Japan (Fukuda et al. 1983), are planted in the habgtats. However, few attempts have yet been made to evaluate how S. charondtt uses these resource-related trees thaL are planted. Therefore, most conservation efforts are carried out with little basis in scientific knowledge and information. An area located on Shichirigaiwa plateau, Hokuto City, Yamanashi Prefecture, central Japan, was afforested by planting with C. sinensis and e. acutissima side by side fbr the purpose of preserving S. charonda populations (hereafter, the afforested area), However, no attempts have yet been made to examine how the tilibrested area is utilized by the butterfly, and whethcr thc area is helpfu1 to maintenance of its populations. In the present study, wc investigate the current status of an atforested area created for the purpose of preserving S. charonda populations, and examined how the area is utilized by the butterfly as a case study.The main purposcs of this study were to examine how S, charonda populations use the atforested area, and as a result, to clari'fy hew to afforest their resource-related trees in a suitable and effective way for conserving the populations of S. charonda. Life history of S. charoncla S. charondu is distributed over the mountainous regions of northern [faiwan, continental China, the Korean Peninsula, and Japan. In Japan, S. charonda is univoltine and the host trees are C. sinensis or C.,iessoensis. On the Kanto Plain ofcentral Japan, the flight season of adults extends from late June to late August. The minimum duration of the egg stage is five days (Kobayashi & Inaizumi, 2002). Larvae feed on leaves until the end of 0ctober, when they reach the 3rd or 4th instar. They descend the trees early in November and over- winter in the litter near tree tmnks. In early spring of the fo11owing year, they return to the budding trees, finish their developmcnt there and pupate in June. Study area At the gentle slope on Shichirigaiwa Tbrrace facing Kamanashi River, in Hokuto City, Yamanashi Prefecturc, central Japan, natural forests consisted of canopy trees of Pinus densij7ora, C. sinensis, C. jessoensis, .htglans mandshurica and Zelkova serrata which are widely distributed (Fig. 1). In particular, many larval host trees o'f S. charonda, C. sinensis or C, jessoensis, are found at landslide sites of the slope, and the density is 50.0 treeslha (Kobayashi et al. 2008), Also on the slope, there is an area planted with a mixture of C. sinensis and e. acutissima side by side (hereafter, the a'fforested area), which was afforested for the sole purpose of preserving S. charonda popu]ations under the government of Nagasaka-[[bwn (Hokuto City at present). That is, the sequence of C, sinensis and the se- quence of e. ac"tissima are arranged in a]ternating rows (Fig, 2). In the a'ffbrested emrea (about 4.0 ha), thc planting interval of C. sinensis and e. ac"tissima is 2 m (Fig. 2). The C 'i.n sinensis and e, acutissima were both about 1 m in height when planted the area in 1982, and therefore, their age is currently estimated to be at least more than 26 years (Hasegawa, unpublished data). The alfbrested area faces a paved (asphalt-surfaced) road and only C. sinensis trees are planted at the edge of the area frLcing the road (Fig, 2). The other edges of the afforested area are in contact with natural forests. Thus, in this paper, only the trees fac- NII-Electronic Library Service The LepidopterologioalLepidopterological SooietySociety of Japan ． ・ 154 Takato KoBAYAsHI， M asahiko K1 rAHARA and Tohru NAKAs 田 zuKA 〕Oln 」 一 一 L 』 Fig ．1． The research site of this study was a gently sloped area on ShichiTigaiwa Terrace facing Kamanashi River， in Hokuto City， Yamamashi Prefecture， central Japan． 广 Ed 一 呂 靄 40伽 ○ （）θ2tis sineηsis ■ QuerCUS acuti5S’ma 囲 Natural Foresヒs Fig ．2． Mimetic diagram of the affforested urca planted with C ． sinen ，yis and 2．σ α 傭 3 吻 α side by side for the puq ）ose of protcction of S． charonda in the upPer part f a gen しly sloped area on Shichirigaiwa Terrace． 一 NII-ElectronicN 工 工 Eleotronio Library Service The LepidopterologicalSocietyLepidopterological Society of Japan Etfects of aifbrested Area on Sasakia charoncla 155 ing the pasJed road of the afforested area are treated as the forest edge of the area (Fig. 2), Materials and methods 1) Density and dbh of C. sinensis and e. acutissima in the affbrested area The densities of C. sinensis and e. acutissima were examined in the atforested area in May, 2003, Tb clarify the difference in the sizes between C. sinensis trees and e. acutissima in the afibrested area, we measured the dbh of 30 trees selected randomly in each area. 2) Number of overwintering larvae of S. charenda and dbh of C. sinensis both in the alforested area and in the surrounding area of natural forests [[b compare the size of C. sinensis trees in the affbrested area and in the surrounding urea of natural fbrests, we measured dbh of 30 trees of C. sinensis randomly selected from each of the afforested area and the surrounding area ofnatural forests. During 15-28 December in 2003, we co]lected litter at the forest floor within a range of O.5 m from the base of the 30 trees selected from each of the afforegted area and the surrounding area of natural forest, and immediately counted the number of S. charondo larvae in each sampie of coliected lit- ter at our laboratory. The stage of the larvae was third or fourt1i instai: ln addition, we se- lected 1 1 C. sinensis trees from the 30 trees selected from the afforested area, which grew at the edge of the allbrested area, and 30 host trees in the surrounding area of natural forest; we compared dbh of C, sinensis and the number of S.