臺灣新發現寬胸蛛屬食蟻蜘蛛之物種分類與蜘蛛絲性質探討（蜘蛛目：姬蛛科）

Taxonomic Identification and Spider Silk Analysis of a New Myrmecophagous Spider of the genera Euryopis (Araneae, Theridiidae) in Taiwan

黃麒倫(Chi-Lun Huang)

指導教授 ： 吳?承

國立臺灣大學/生命科學院/生化科技學系/碩士(2020年)

https://doi.org/10.6342/NTU202000472

摘要

蜘蛛絲為具有優異機械性質與生物親和性的材料，因此具有廣泛用途，如醫療材料、紡織材料、藥物載體及疏水蛋白質製程改善等。而不同生活形態的蜘蛛具有不同的蜘蛛絲機械性質。例如圓網蜘蛛曳絲相對於遊獵蜘蛛具有較強剛性、延展性與韌性。2017年芝山文化生態綠園志工葉黎明老師在臺北市士林區芝山岩地區（25o06’15" N, 121o31’49" E）發現外觀與行為與舉尾蟻Crematogaster sp.相似的食蟻蜘蛛，其會將腹部抬起並擺動第四步足。這樣特殊的行為與常見的結網蜘蛛與游獵蜘蛛截然不同，然當前並未有相似行為蜘蛛的曳絲機械性質被研究過。因此本研究希望藉由外部形態特徵與基因條碼檢索及親緣樹分析對該蜘蛛進行物種鑑定，並分析該蜘蛛曳絲機械性質。
外部形態鑑定與分子親緣結果皆顯示目標蜘蛛與姬蛛科（Theridiidae）寬胸蛛屬（Euryopis）蜘蛛最為接近，顯示目標蜘蛛可能屬於寬胸蛛屬。然而目前線上資料庫中寬胸蛛屬外部形態與序列資料並不完整，因此若要再進一步對目標蜘蛛鑑定則需要與世界已發現75種寬胸蛛屬蜘蛛模式標本進行比對並補足缺乏的基因資料（僅有12%寬胸蛛屬蜘蛛具有完整序列資料）。
目標蜘蛛曳絲機械性質如下：平均直徑1.57 ± 0.23 µm，剛性0.62 ± 0.01 GPa，延展性0.38 ± 0.02 ln(L/L0)，抗拉強度90.9 ± 24.4 MPa，韌性22.6 ± 5.9 MJ/m3，與平均蜘蛛曳絲性質比較有較佳延展性，但其剛性、抗拉強度與韌性相對較差。未來應可嘗試分析目標蜘蛛曳絲序列與其延展性關係，並應用於強化合成蜘蛛絲延展性。

關鍵字

寬胸蛛屬 ； 姬蛛科 ； 親緣樹分析 ； 食蟻蜘蛛 ； 蜘蛛絲

並列摘要

Spider dragline silk is a biomaterial with strong mechanical properties and bioaffinity. It has various applications, such as medical material, textile material, drug carrier and hydrophobic protein production process improvement. Dragline silk from spiders with different life styles has different properties. For example, orb spider dragline silk has better stiffness, extensibility and toughness than dragline silk from wanderer spiders. In 2017, an unknown myrmecophagous (feeding on ants) spider was recorded at Zhishanyan in Taipei, Taiwan (25o06’15” N, 121o31’49” E). This spider typically poses steadily with its abdomen upward and waves its fourth pair of legs. The spider’s unique behavior and appearance are similar to Crematogaster ants that coexist in the same habitats. The Crematogaster ants, also commonly named as cocktail ants, have a habit of raising their abdomens when alarmed. This coincidence in behavior patterns has intrigued us as an aspect of biomimicry. However, there are no reports of the dragline silk properties of spiders with similar behavior. We seek to identify the spider in a systematic way by characterizing its morphological features, gene barcoding and phylogenetic tree identity, and we also try to analyse the dragline silk mechanical properties of the unknown spider.
Both the morphological characteristics and the molecular phylogenetic analysis indicate that the unknown spider primarily belongs to Euryopis, Theridiidae. Currently, there are 75 reported species of Euryopis spiders worldwide, however, not all taxonomic information (morphological and DNA barcode data) are accessible.
The target spider’s dragline silk exhibited diameter 1.57 ± 0.23 µm, stiffness 0.62 ± 0.01 GPa, elasticity 0.38 ± 0.02 ln(L/L0), tensile strength 90.9 ± 24.4 MPa and toughness 22.6 ± 5.9 MJ/m3. Dragline silk from the target spider exhibits high elasticity. Further studies are required to identify the target spider’s dragline silk amino acid sequence and reveal the relationships between silk sequence and elasticity properties.

並列關鍵字

Euryopis ； Theridiidae ； phylogenetic tree ； myrmecophagous spider ； spider silk

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