徐堉峰Hsu, Yu-Feng林育綺Lin, Yu-Chi2020-10-192025-02-272020-10-192020http://etds.lib.ntnu.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=id=%22G080143001S%22.&%22.id.&http://rportal.lib.ntnu.edu.tw:80/handle/20.500.12235/111534各式各樣防禦捕食者的策略在世界各地各類生態系出現，可見捕食是顯著而重要的演化驅力。在多樣的捕食策略中，刺是顯而易見的防禦策略，並且許多生物用以對抗天敵。鱗翅目的刺蛾幼蟲以多樣化著名且不同齡期間刺的形態會改變，正好適合作為研究防禦機制與其他特徵演化的材料。本研究第一章概括介紹刺蛾科的命名、生活史與分類處理狀況。第二章以飼養經驗與前人研究歸納多樣的刺蛾幼蟲類型，記錄種內不同齡期間刺形的變異情形，並且以電子顯微鏡比較其他防禦機制—刺毛—在刺蛾、毒蛾與枯葉蛾幼蟲的異同。第三章基於第二章的結果探討刺於刺蛾科內的演化。過去關於刺蛾的親緣關係研究主要基於美洲的樣本，其曾推論刺蛾之刺為單一起源並且無刺型幼蟲為祖先型。此推論與更早提出的假說相反，且刺蛾為廣分布的物種，加入其他地理區之樣本後結果不一定相同。因此，本研究第三章，首先取來自亞洲、澳洲、北美與南美的45個內群與8個外群之五個基因片段建立親緣關係樹，其後分析刺的特徵演化。研究結果顯示刺為單一起源，並且無刺型幼蟲多次獨立由有刺型幼蟲平行演化而來。本研究第三章，利用第二章所得之親緣關係樹進一步探討刺與警戒色的演化關係。根據前人研究，警戒色的防禦可分為公開防禦與不公開防禦。在公開防禦的警戒色演化方面，過去的研究曾提出不同的假說：警戒色演化出來之後，在刺的投資上可減少；由於刺的防禦屬於公開防禦，因此不需演化出強烈的警戒色；即使有刺為次級防禦，若演化出強烈的警戒色，仍會因為較易被天敵發現而使適存度下降。本研究以特徵演化探討刺的防禦強度與警戒色的對比強度之間的演化關係，結果顯示防禦強度增強，警戒色也隨之增強，除此之外本研究結果支持「警戒色演化出來之後，在刺的投資上可減少」之假說。Anti-predator strategies occur in every biome of the world, implying that predation is a potent selective force and thus of immense ecological and evolutionary significance. Spines are one kind of obvious anti-predator strategy to avoid predation. Larvae of the family Limacodidae, commonly known as ‘slug’ caterpillars, are well known because of the widespread occurrence of spines with urticating properties, a morpho-chemical adaptive trait that has been demonstrated to protect the larvae from natural enemies. However, while most species are armed with rows of spines, slug caterpillars are morphologically diverse with some species lacking spines. Since the Limacodidae have various types of larvae, it provides great opportunities and materials to compare and understand the defensive mechanism in nature. The aim of this study is to investigate the spine evolution and the evolutionary relationships between spine and other traits. In chapter 1, the Limacodidae is general introduced. In chapter 2, the spine character are explored through rearing larvae of the Limacodidae; the types of slug caterpillars are recorded for making generalizations. Moreover, other defensive mechanism, such as spicules, on limacodids and other caterpillars are investigated and compared with scanning electron microscopy (SEM). Based upon the results achieved chapter 2, the character evolution are investigated in chapter 3. It has been demonstrated that the evolution of spines in slug caterpillars may have a single origin, and that this trait is possibly derived from non-stinging slug caterpillars, but these conclusions were based on limited sampling of mainly New World taxa; thus, the evolution of spines and other traits within the family remains unresolved. I analyzed morphological variation in slug caterpillars within an evolutionary framework to determine the spine evolution with samples from Asia, Australia, North America and South America. The phylogeny of the Limacodidae was reconstructed based on a multi-gene dataset comprising five molecular markers (5.6 Kbp: COI, 28S, 18S, EF-1α, and wingless) representing 45 species from 40 genera and eight outgroups. Based on this phylogeny, limacodids are inferred to evolve from a common ancestor in which the larval type possessed spines, and then slug caterpillars without spines evolved independently multiple times in different continents. In chapter 4, the correlation of the spines and the warning coloration is investigated. Aposematism is recognized as one of the important ways to avoid attacks from natural enemies. With regard to the previous aposematism studies about the initial evolution in overt defenses: in 1890, Poulton claimed that some colorations exaggerate threat posed by physical defenses; in 1986, Leimar et al. argued that aposematism may evolve when it presents a more cost-effective method of deterrence; in 2005, Speed and Ruxton suggested that investment in spines and toxins evolving but then diminishing as aposematic displays subsequently evolve; in 2019, Caro and Ruxton proposed that the investment in signaling about spines is lower. The evolution of aposematism in slug caterpillars is explored to examine the previous hypotheses. The results suggest that the conspicuousness is higher when the length of spines and protuberances is longer in nettle slug caterpillars.親緣關係特徵演化防禦平行演化phylogenycharacter evolutiondefenseparallel evolution