台灣寬尾鳳蝶的習性與生態需求之研究

Abstract

台灣寬尾鳳蝶(Agehana maraho(Shiraki& Sonan))是台灣特有的珍稀保育類蝴蝶，自1932首次被發現，1934年命名發表迄今已超過70餘年，期間雖然有部分學者、昆蟲愛好人士對此蝶的生活史、部分生態資料進行研究與收集，還是有些基礎生態需求、行為、習性等問題尚待釐清，而且物種保育經營與管理上仍需更充分的研究以建構一完整有系統的生態資料以供作依據。 本研究調查台灣全島各主要台灣檫樹（Sassafras randaiense）分佈的地區，針對台灣寬尾鳳蝶選擇產卵植株的條件、幼生期出現時間及生長發育各階段之生態需求、蛹的化性及越冬蛹越冬條件等項目進行研究，發現雌蝶偏好產卵於陽性環境的台灣檫樹成熟葉片表面上，產卵時間從四月下旬到八月上旬；一、二齡幼蟲由於移動性較差，生活在與卵相似的環境，三、四齡之後的幼蟲則會移動至較為隱蔽的環境。幼生期發育過程面臨各種生存壓力，如捕食、寄生、病菌感染等。此外台灣寬尾鳳蝶藉由不固定蛹期天數以分散遭遇不良環境的風險；研究尚發現溫度為影響越冬蛹越冬成功與否的重要因子之ㄧ。 台灣檫樹於森林自然演替過程中族群逐漸式微，幼苗更新情況不良，有被其他植物取代之趨勢；加上歷年台灣寬尾鳳蝶觀察記錄之數量亦隨時間遞減甚劇，亟需人為長期介入其棲息地的經營與管理。Agehana maraho is a large, beautiful, endangered swallowtail butterfly. Although it was discovered as early as 1932, information on its ecological requirements, behaviors, habits are still insufficient, which is an obstacle to successful conservation of this precious butterfly species. The study is to survey the known colonies of Sassafras, the sole larval host of A. maraho, and to investigate various factors on the ecological requirements of this endangered swallowtail butterfly, with the hope that the results of the investigation may help create meaningful conservation strategies for this species The result of the study has proved that the oviposition site for A. maraho is restricted to the upper surface of mature leaf of the hostplant, and bias to the host plant on sunny habitats. The adult laid eggs from April to August. The young larva in first and second instar inhabit on exposed leaves, the larva after third instar inhabit on leaves under shady condition. Moreover, it was found that various factors, such as predation, parasitism, and pathogen infection, may threaten the survival of various stages of the butterfly. We also discovered that the voltinism of this species is not fixed.