以生態、形態及分子證據探討利用山漆莖屬黃蝶之系統分類位置

Abstract

寄主之利用可能造成植食性昆蟲之族群分化進而達成同域種化。黃蝶(Eurema hecabe Linnaeus,1758)為昆蟲中著名的多表現型(polyphenism)範例，在台灣地區黃蝶可利用豆科(Fabaceae)、鼠李科(Rhamnaceae)、大戟科(Euphorbiaceae)的植物做為其幼生期之寄主。日人針對日本地區黃蝶研究，將食用鼠李科及部分豆科植物之黃色型緣毛黃蝶自黃蝶中分出，為北黃蝶(E. mandarina)。過去雖有部分研究探討，台灣地區食用大戟科山漆莖屬(Breynia)做為寄主之黃蝶分類地位尚不明確，因此本研究將台灣地區之黃蝶依據其寄主植物分為北黃蝶、豆科型黃蝶、大戟科型黃蝶三群進行探討，以確立利用大戟科山漆莖屬(Breynia)之黃蝶的分類地位。 生態學研究結果發現三型黃蝶之發育起點溫度接近，但北黃蝶的有效積溫值較高，且三型黃蝶生長發育之最適溫區不同。將三型黃蝶的後翅翅型利用普氏疊合後(Generalized Procrustes Analysis, GPA)進行典型變異分析(Canonical variates analysis, CVA)有顯著差異，大戟科型黃蝶的前翅翅型進行典型變異分析亦與其他兩型有顯著差異。三型黃蝶的雌蝶背面之紫外光翅紋反射格式也存在差異。進行網狀親緣關係(hapoltype network)之比較，在wingless片段與RpS2片段大戟科型黃蝶皆能自成一群。wingless片段與RpS2片段之Fst值則顯示大戟科型黃蝶與其他兩型黃蝶之基因交流受到限制。綜合本研究以及過去對於台灣地區黃蝶之相關研究推斷，認為台灣地區利用大戟科山漆莖屬之黃蝶為一隱蔽種。

Host shift might cause differentiation between populations of phytophagus insects and lead to sympatric speciation in the end. Eurema hecabe, a polyphenic butterfly who uses Fabaceae, Rhamnaceae and Euphorbiaceae plants as hosts The past studies discriminated the yellow wing fringe form of E. hecabe that using Rhamnaceae and Fabaceae plants as a distinct species called E.mandarina. The Euphorbiaceae-feeding populations only use Breynia species as hosts and its systematic status is not clear yet. This study aims to clarify the systematic status of the Breynia-feeding E. hecabe in Taiwan. I separated Taiwanese populations of E.hecabe complex into three groups according to their hosts; they were Eup-type, Fab-type and E. mandarina, respectively. In the ecological investigations, threshold temperature of development were similar among three types, though E. mandarina had higher effective accumulated temperature. The optimum temperature ranges of the three types were different. Results of canonical variates analysis showed that shape of forewing was significantly different between Eup-type and the other two, and shape of hind wing was different among the three types. Female UV reflection pattern of three types were different. The Eup-type formed a monophyletic group in the molecular analyses based on wingless gene and GAPDH gene. The high value of Fst illustrated that gene flow between Eup-type and the other two was limited. To integrate the results of ecological experiments, morphological measurements, and molecular analysis, I concluded that the Breynia-feeding E. hecabe should be a cryptic species.