以形距分析探究大白斑蝶之分布與分化

A morphometric study of the disjunct distribution and differentiation of Idea leuconoe (Lepidoptera: Nymphalidae)

林育綺(Yu-Chi Lin)

指導教授 ： 徐堉峰

國立臺灣師範大學/理學院/生命科學研究所/碩士(2012年)

摘要

生物的分布可顯示生物適應某環境條件後的生理特性與分布限制等，其中生物間斷分布的形成原因包含長距離擴散與隔離分化。依照間斷分布之生物的整體形態相似度與分布地理區的形成歷史可推測生物形成間斷分布的機制。大白斑蝶族群隔離分布於太平洋西部的琉球群島、台灣及菲律賓地區，這些島嶼的形成先後與海平面上升將陸地隔離的先後有關。本研究以地標點分析不同族群─沖繩群島、八重山群島、台灣東北角、綠島、蘭嶼、恆春半島及菲律賓─的大白斑蝶翅紋相似程度，檢測大白斑蝶族群的形成先後，推論其間斷分布的形成機制是隔離分化、一次擴散事件或多次擴散事件。亦針對幼蟲的形態加以分析，探討不同地點之間幼蟲形態上的差異。根據成蝶前翅群集分析、主成分分析、典型變異分析結果顯示大白斑蝶之間斷分布至少由兩次擴散事件所造成。成蝶前翅以PERMANOVA分析結果顯示所有族群之間皆有顯著差異，而幼蟲形態分析之結果顯示，部分族群之間有顯著差異。其中幾乎所有的分析結果皆顯示綠島為獨立的族群，因此支持1928年楚南所提出的分類處理。其他分類與保育議題於文中有進一步討論。

關鍵字

間斷分布 ； 大白斑蝶 ； 地標點分析 ； 翅紋

並列摘要

Species distribution usually reflects its physiological characters and survival restriction under environmental conditions. Disjunct distribution of species can be resulted from long-distance dispersal or vicariance. According to the phylogeny of the species and the history of its geographical distribution areas, we can infer which mechanism may be responsible to disjunct distribution of the species. Idea leuconoe, a famous butterfly belonging to Nymphalidae, form isolated populations on isolated on islands of Southeast Asia. The forming series of Ryukyu Islands and Taiwan was caused by sea level changes and volcanic events in the different geological time. In this study, land-mark analysis was used to evaluate the wing pattern similarity between different populations of Idea leuconoe including Okinawa Island, Yaeyama Island, northeastern Taiwan, Green Island, Ochid Island and Hengchun Peninsula. Three alternative hypothesized mechanisms causing disjunct distribution of I. leuconoe were tested. The variation of larval morphology at different site were also examined. The results of cluster analysis, principal component analysis (PCA) support that the disjunct distribution of I. leuconoe was caused by at least two dispersal events. Taxonomic treatments proposed by Sonan, who regarded the Green Island population as a uniqual subspecies was supported by all analysis in this study. The details of taxonomy and conservation issue are also discussed herein.

並列關鍵字

disjunct distribution ； Idea leuconoe ； land-marks analysis ； wing pattern

參考文獻

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