Abstract An area of about 2.7 ha at Dawu (Taitung County, southeastern Taiwan) where several species of Euploea and Tirumala danaine butterflies form a massive overwintering assemblage in winter is known as the largest danaine butterflies overwintering site in Taiwan. From November 2004 to March 2005, ecological studies were conducted by the marked-released-recaptured method and direct observations. The results showed that the most abundant species in the overwintering butterfly community was Euploea sylvester swinhoei Wallace & Moore, which comprised > 60% of the total number of sampled individuals. The number of overwintering butterflies increased by November and reached the highest peak in late January. Then, the number of overwintering butterflies slowly decreased with emigration of the danaine butterflies. The maximum number of individuals may reach 320,000. In the daytime, Tirumala spp. prefer to cluster on trees higher than 6 m while Euploea spp. prefer to cluster on shrubs or trees lower than 6 m; however, at night, both of them choose to cluster on trees higher than 6 m. The individual distance among Tirumala spp. is short so they often cluster as a ball. The predators observed during the study included the spiders Nephila pilipes (Fabricius) and N. clavata Koch and the Black bulbul Hypsipetes madagascariensis (Müller).
摘要 台灣台東大武地區佔地約 2.7 公頃的斑蝶越冬棲息地，每年冬天會有許多紫斑蝶類與青斑蝶類在此越冬，是目前台灣已知大型的斑蝶越冬棲息地之一。本研究自 2004 年 11 月至 2005 年 3 月止，以標記再捕法和觀察方式，進行斑蝶越冬生態研究。研究結果顯示：在越冬斑蝶群聚中，以斯氏紫斑蝶數量最多，約佔所有越冬斑蝶的 60﹪以上；越冬斑蝶的族群數量從 11 月起逐月增加，至次年 1 月下旬達最高峰；其後族群數量隨著斑蝶逐次遷離越冬棲息地而減少；族群數量最大可達 32 萬隻。白天青斑蝶屬 (Tirumala spp.) 偏好停棲於 6 公尺以上的喬木，紫斑蝶屬 (Euploea spp.) 則偏好停棲在 6 公尺以下的灌木或小喬木，夜間二者均選擇停棲在 6 公尺以上的喬木。在天敵觀察方面，有兩種蜘蛛—人面蜘蛛 (Nephila pilipes (Fabricius)) 和橫帶人面蜘蛛 (N. clavata Koch) 和一種鳥類—紅嘴黑鵯 (Hypsipetes madagascariensis (Muller)) 會捕食越冬斑蝶。
| Key words: Euploea, Tirumala, community structure, population estimation | | 關鍵詞: 紫斑蝶屬 (Euploea)、青斑蝶屬 (Tirumala)、群聚結構、族群估算。 |
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