台東紅葉村台東蘇鐵自然保留區東陞蘇鐵小灰蝶生態研究及蝶相（二）
The Ecological Studies of Chilades pandava peripatria (Lepidoptera: Lycaenidae) and Butterfly Fauna in the Taitung Cycad Nature Reserve Ⅱ
國立臺灣師範大學生物學系－－－－－徐堉峰 Yu-Feng Hsu
楊平世 Pin-Shih Yang
－摘要 －
東陞蘇鐵小灰蝶 Chilades pandava peripatria，(又稱蘇鐵綺灰蝶)，依賴台灣特有保育類植物—台東蘇鐵Cycas taitungensis(原名台灣蘇鐵)為寄主植物。本研究主要說明東陞蘇鐵小灰蝶與台東蘇鐵的關係為一長時間共同演化之產物，乃因東陞蘇鐵小灰蝶的生存完全依賴蘇鐵新芽的存在與否。由於蘇鐵樹形優美，廣為各地區佈景植物所採用，因此台灣各地常可發現東陞蘇鐵小灰蝶的蹤跡。但其出現情形並不穩定，常因區域性的蘇鐵新芽不足或是環境不適而造成該區的東陞蘇鐵小灰蝶滅絕。區域性的東陞蘇鐵小灰蝶族群，有賴台東蘇鐵自然保留區內的核心族群的供給以維持。
東陞蘇鐵小灰蝶在各地出現之嚴重食害可能是因為人為大量栽培外來種琉球蘇鐵Cycas revoluta的結果。該種蘇鐵在台灣之物候表現為開芽期長、側生不定芽多且密且開芽高峰與台東蘇鐵不相同。如此，東陞蘇鐵小灰蝶因可利用外加的琉球蘇鐵新芽而使其族群過度膨脹，進而加大對台東蘇鐵食害壓力。反觀東陞蘇鐵小灰蝶族群本身而言，也易造成因其族群過大而與台東蘇鐵間共演化關係呈現不穩定狀態，最後亦導致東陞蘇鐵小灰蝶本身滅亡。
本研究即以東陞蘇鐵小灰蝶族群在各地的群族數量、台東蘇鐵之物候學以及其全年之開芽情況，用以作為兩者保育經營、監控東陞蘇鐵小灰蝶族群之重要依據。此成果亦提供動物界中少見的無脊椎動物遷移模式之本土實證教材。
另外，台東蘇鐵保留區所在地形特殊且植被豐富而多樣化，使區內蝶類資源豐富而甚具特色，本研究亦同時初步調查了區內的蝶類相及特性。
關鍵字：台東蘇鐵、東陞蘇鐵小灰蝶、蘇鐵綺灰蝶、共同演化、核心族群、物候學、蝶相、植被壓縮、特有種、紫蝶幽谷。
ABSTRACT
The larva of cycad blue, Chilades pandara peripatria, is exclusively associated with cycad plants including the endemic, endangerous Taiwan cycad Cycas taitungensis. This study is to investigate the evolutionary associations between the cycad blue and its host plants. Cycads are extensively used as ornamental plants in urban areas, as a result, cycad blue frequently occurs at various sites in Taiwan, but at most sites the local population fluctuates considerably, and the butterfly relies on the core population in the Taitung Cycad Nature Reserve for population sustaining.
The cycad blue was not a cycad pest until recently. The reason why it outbreaks from time to time in recent years probably involves the introduction and extensive cultivation of another cycad species, C. revoluta, originally from the Ryukyus. The phenology of the introduced cycad differs from the Taiwan cycad by having 1) pro-longed budding period, 2) extensive auxiliary buds, and 3) budding peaks in different time of the year. Consequently the cycad blue has extra food supply when soft tissue of Taiwan cycad is in short supply, and the butterfly population overgrows, that imposes serious damages to Taiwan cycads, and the butterfly itself is also subject to unstable population fluctuations, and liable to go extinct due to choas.
This study investigates and monitors the population size of the cycad blue and cycads at various sites. The collected data will provide basis for conservation of the Taiwan cycad and the associated cycad blue. The result will also offer a model on invertebrate migration patterns that have not been studied extensively in Taiwan.
Key word：Chilades pandara peripatria, Cycas taitungensis, core evolution, C. revoluta, butterfly favna, flora compression, endemic species, butterfly valley