I saw many butterflies on the streets of Shilin, Taiwan, one of which was the dark blue tiger. The dark blue tiger is a danaid butterfly found across the Indian subcontinent and Southeast Asia. Tirumala septentrionis closely resembles the blue tiger (Tirumala limniace), but differs on the upperside in having a darker ground colour and narrower, more distinct, bluer semihyaline markings.
The dark blue tiger displays gregarious migratory behavior in southern India, where it is one of the predominant species — making up around 78% of individuals during the region's mass butterfly migrations. Both males and females migrate in roughly equal numbers. The species produces more than one generation per year.
Adult butterflies favor heavily shaded, humid forest environments, largely because one of the larval host plants used by this species — Heterostemma brownii, documented specifically in Taiwan — is a shade-loving plant that thrives on the floor of humid woodlands. Flight is slow, and the adults are frequent flower visitors. Across both life stages, the species relies on chemical defense: larvae sequester plant alkaloids from their host plants, while adults take in additional protective compounds from nectar plants, arming them against predators at every stage of life.
我在台灣士林的街頭看到了許多蝴蝶，其中一種是小紋青斑蝶。小紋青斑蝶屬於斑蝶亞科，分佈於印度次大陸和東南亞各地。這種蝴蝶（學名：Tirumala septentrionis）與淡紋青斑蝶（Tirumala limniace）外形極為相似，但其翅膀上側底色較深，且半透明斑紋更窄、更明顯，色調也更偏藍。
小紋青斑蝶在印度南部會群居遷徙，是當地遷徙季節的主要物種之一——其個體數量約佔總數的 78%。雌雄個體的遷移數量大致相當。該物種一年多世代。
成蟲偏好遮蔽度高、潮濕的森林環境中活動，這主要歸因於該物種的一種幼蟲寄主植物——布朗藤（Heterostemma brownii，該寄主記錄主要見於台灣）——屬於喜陰植物，常生長於潮濕林地的底層。成蟲飛行緩慢，好訪花。該物種在各個生命階段均依賴化學防禦機制：幼蟲從寄主植物中富集植物鹼，成蟲則從蜜源植物中攝取額外的保護性化合物，從而在生命週期的每一階段都具備抵禦捕食者的能力。
Notes 筆記
- The dark blue tiger is a danaid butterfly found in the Indian subcontinent and Southeast Asia.
- Dark blue tiger (Tirumala septentrionis) closely resembles Blue tiger (Tirumala limniace). From T. limniace it differs on the upperside in the ground colour being darker and the semihyaline markings narrower, more distinct, and of a bluer tint.
- The dark blue tiger shows gregarious migratory behaviour in southern India. This species is one of the predominant species (78%) during the migratory season in southern India during which many species migrate. Both males and females appear to migrate in equal numbers.
- More than one generation per year. Adult butterflies prefer to move in highly shaded and humid forest environments, because the host plant used by the larvae of this species, Heterostemma brownii, is a shade plant and likes to be at the bottom of humid woods. The flight is slow and loves to visit flowers. In the larvae and adult stages, different plant alkaloids are ingested through the host and nectar plants respectively as a weapon to defend against natural enemies.
- 小紋青斑蝶又名薔青斑蝶、小紋淡青斑蝶、細紋青斑蝶，為蛺蝶科青斑蝶屬下的一個種。是一種生活在印度次大陸和東南亞的蛺蝶科蝴蝶。
- 小紋青斑蝶與淡紋青斑蝶非常相似。與淡紋青斑蝶不同的是，它的上側底色更深，半透明斑紋更窄、更明顯，色調更藍。
- 小紋青斑蝶在印度南部有群居遷徙行為。它是印度南部遷徙季節的主要物種之一（78%）。雄性和雌性的遷徙數量似乎相同。
- 一年多世代。成蝶偏好於遮蔽度高、潮濕的森林環境活動，因本種幼蟲利用的寄主植物布朗藤是陰性植物，喜歡在潮濕的樹林底層。飛行緩慢，好訪花。在幼蟲及成蟲期會分別透過寄主及蜜源植物攝入不同的植物鹼作為防禦天敵的武器。
References 參考資料
- Wikipedia: Tirumala septentrionis
- 臺灣蝴蝶網路圖鑑: 小紋青斑蝶
- 維基百科: 小紋青斑蝶
Posts: Insects by Name 昆蟲-英文名錄
Posts: Insects by Order/Family 昆蟲-目/科錄