臺灣產貓蛛科蜘蛛之系統分類和都市化對其遺傳多樣性之影響
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2024
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在面臨生物多樣性持續流失的壓力下，加速釐清野生物的多樣性資訊、親緣關係和生態演化是生物多樣性保育的重要基礎。貓蛛科蜘蛛為狼蛛總科的成員，是物種多樣性相當高的遊獵型蜘蛛，廣泛分布於草生地、灌木叢和樹冠層等不同棲息地，也是都市、農業生態系中相當普遍的蜘蛛之一。牠們在臺灣的物種多樣性是被大幅低估的，因此本研究首先對臺灣產貓蛛科進行全面性的分類整理，並使用整合性物種界定方法探討牠們的物種界限，包含ABGD、ABSP、bPTP、 GMYC、BPP等。根據形態證據，共整理出5屬16種，包含7個新種（Hamataliwa cordivulva sp. nov.、Hamat. leporauris sp. nov.、Oxyopes hasta sp. nov.、O. taiwanensis sp. nov.、Tapponia auriola sp. nov.、T. parva sp. nov.、T. rarobulbus sp. nov.）和7個新紀錄種（Hamadruas hieroglyphica (Thorell, 1887)、Hamat. foveata Tang& Li, 2012、O. fujianicus Song & Zhu, 1993、O. sertatoides Xie & Kim, 1996、O. striagatus Song, 1991、O. sushilae Tikader, 1965、Peucetia latikae Tikader, 1970），而 P. formosensis Kishida, 1930 則列爲疑問種。依據K2P模型計算樣本間的COI基因遺傳距離，結果顯示以遺傳距離3%為閾值可有效鑑定多數物種，然而部分物種間的界限並不明確，例如 O. sertatus 和 O. taiwanensis sp. nov.，以及 Hamat. cordivulva sp. nov. 和 Hamata. foveata 之間都有明確的生殖結構差異，但是ABGD、ASAP、bPTP、GMYC等方法都無法區別；相反的，T. parva sp. nov. 的種內遺傳距離大於4%，但未有明確的形態分化證據。此外，本研究透過5個分子遺傳標記（12S rRNA、18S rRNA、28S rRNA、COI、histone H3）來釐清貓蛛科內的親緣關係，資料集共包含6屬42種。最大似然法（ML）和貝葉斯推理法（BI）所重建的分子系統發育樹支持貓蛛科包含3大支系，包括：（1）Peucetia和 Tapinillus；（2）Oxyopes；（3）Hamadruas、Hamataliwa和Tapponia。除了 Tapponia 以外，各屬皆為單系群，但Hamataliwa 和 Tapponia 之間的關係和屬徵定義有待釐清。透過幾何形態學方法分析背甲形狀和眼式位置的變異，發現除了Hamadruas和Oxyopes的形態空間完全重疊之外，背甲形狀在不同性別及各屬之間皆具有明顯的差異，並且展現系統發育信號；同時，我們也探討背甲形狀變異與貓蛛的步足形態與活動模式之間的關聯，發現貓蛛科可能起源於較頻繁移動的活動模式，其步足相對較長、背甲也具有更寬大的胸區，其後演化出定棲活動模式的類群，其步足比例較短，背甲胸區則未特別突出。斜紋貓蛛（O. sertatus）是臺灣低海拔山區、農地及都市綠地廣泛分布的物種，因此是探討都市化過程對野生物遺傳多樣性影響的理想材料。目前有兩個假說被提出，即「都市破碎化模型」預期都市對生物的擴散是種屏障，而「都市促進模型」則預期都市對適應者的擴散來說扮演著廊道的作用。我們於台中及南投地區選取17個不同都市化程度的樣點，利用4 km2（地景尺度）及0.25 km2（局部尺度）範圍內土地利用組成作爲量化都市化程度的依據，並利用COI與RAD-seq資料分析斜紋貓蛛族群內的遺傳變異、族群間的遺傳分化和遺傳結構。結果顯示，許多遺傳多樣性指數都有伴隨都市化程度增加而下降的趨勢，特別是雜合度觀測值（observed heterozygosity, HO）在0.25 km2及4 km2尺度下，以及對偶基因豐富度（allelic richness, Ar）在4 km2尺度下皆有顯著的降低，不過核苷酸多樣性則不受影響；此外，族群間的COI及RAD-seq遺傳分化指數，在都市區域顯著高於非都市區域。這些結果皆符合「都市破碎化模型」的預期，即都市內因自然棲地有限、面積小且互相隔離，導致小族群、遺傳漂變作用增強及遺傳多樣性的流失；不過STRUCTURE和PCA分析結果並未顯示有族群遺傳結構，表示都市和非都市族群間仍有相當程度的基因流動。總結來說，本論文作為首次探討全面探討貓蛛科蜘蛛的物種多樣性和親緣關係，強調了形態診斷與其他整合性物種界定方法對精確評估物種多樣性的重要性，以及背甲形態在親緣關係和活動型態適應的關聯；最後，也突顯改善都市自然棲地的品質與連結的需求，以確保都市野生物、生態系統服務與功能的永續發展。
In the face of the ongoing loss of biodiversity attributed to anthropogenic pressures, a comprehensive understanding of species diversity, phylogenetic relationship, and the evolutionary history of wildlife is fundamental knowledge for biological conservation. The family Oxyopidae (lynx spider) is members of the superfamily Lycosoidea and represents one of the most diverse and widespread groups of cursorial spiders. They are widely distributed in various habitats such as grasslands, shrubs, and forest canopies and are also common in urban and agricultural ecosystems. The species diversity of lynx spiders in Taiwan was significantly underestimated. Therefore, this study first conducted a comprehensive taxonomic revision of Taiwanese lynx spiders and investigated their species boundaries using an integrative species delimitation approach by including morphological and molecular evidence from ABGD, ASAP, bPTP, GMYC, and BPP analyses. Based on morphological evidence, 16 species in five genera were recognized, including seven new species (Hamataliwa cordivulva sp. nov., Hamat. leporauris sp. nov., Oxyopes hasta sp. nov., O. taiwanensis sp. nov., Tapponia auriola sp. nov., T. parva sp. nov., T. rarobulbus sp. nov.) and seven newly recorded species (Hamadruas hieroglyphica (Thorell, 1887), Hamat. foveata Tang& Li, 2012, O. fujianicus Song & Zhu, 1993, O. sertatoides Xie & Kim, 1996, O. striagatus Song, 1991, O. sushilae Tikader, 1965, Peucetia latikae Tikader, 1970), while P. formosensis Kishida, 1930 was listed as a dubious species. The results showed that using a COI genetic distance (K2P) threshold of 3% can effectively delineate most species. However, the boundaries between some species are ambiguous. Oxyopes sertatus and O. taiwanensis sp. nov., as well as Hamat. cordivulva sp. nov. and Hamat.foveata, have distinct morphological differences in genitalia, but methods such as ABGD, ASAP, bPTP, and GMYC cannot distinguish them as independent species. Conversely, T. parva sp. nov. has a genetic distance greater than 4% without clear morphological differentiation. Additionally, this study reconstructed the molecular phylogeny of the lynx spider using five genetic markers (12S rRNA, 18S rRNA, 28S rRNA, COI, and histone H3) and a dataset included six genera and 42 species. Phylogenetic trees reconstructed using maximum likelihood (ML) and Bayesian inference (BI) methods support three major clades within the Oxyopidae: (1) Peucetia and Tapinillus, (2) Oxyopes, and (3) Hamadruas, Hamataliwa, and Tapponia. All genera except Tapponia are monophyletic. The relationship between Hamataliwa and Tapponia and their generic definitions require further clarification. Through geometric morphometric analysis of carapace shape indicated significant differences in carapace shape between different sexes and genera, with phylogenetic signals is presented. The analysis also explored the correlation between carapace shape variation and leg morphology with the mobile lifestyle of lynx spiders, suggesting that Oxyopidae may have originated from more mobile ancestors, characterized by wider thoracic region of carapaces and relatively longer legs, and subsequent evolution led to sedentary lifestyles, with less pronounced thoracic region and relatively shorter legs.Oxyopes sertatus, widely distributed in low-elevation mountains, farmlands, and urban green spaces in Taiwan, is an ideal species to investigate the impact of urbanization on genetic diversity. Two hypotheses have been proposed: the urban fragmentation model predicts, which predicts urbanization acts as barrier to dispersal, and the urban facilitation model, which predicts urban habitats as corridors for urban adapters. I selected 17 sites with varying degrees of urbanization in Taichung and Nantou and quantified the urbanization level using land use composition within 4 km² (landscape scale) and 0.25 km² (local scale) grids. The genetic diversity, differentiation, and population structure were assessed using COI and Restriction site associated DNA sequencing (RAD-seq) data. The results indicated a trend of decreasing genetic diversity indices with increasing urbanization level, particularly a significant reduction in observed heterozygosity (Ho) at both scales and allelic richness (Ar) at the landscape scale, although nucleotide diversity was not affected. Additionally, average genetic differentiation (FST) among populations in urban region was significantly higher than in non-urban region. These findings support the urban fragmentation model, suggesting that limited and isolated natural habitats in the city lead to small populations, increased genetic drift, and loss of genetic diversity. Nevertheless, STRUCTURE and PCA analyses did not show population genetic structure, indicating substantial gene flow between urban and non-urban populations.In conclusion, this dissertation is the first comprehensive study of diversity and phylogenetic relationships of lynx spiders, highlighting the importance of morphological diagnostics and integrative methods for accurate species diversity assessment and the significance of carapace morphology as a phylogenetic character and its implications for evolutionary adaptation of lifestyle. Finally, this study emphasizes the urgent necessity of improving the quality and connectivity of nature habitats in cities to ensure the sustainability of wildlife and urban ecosystem services and functions.
In the face of the ongoing loss of biodiversity attributed to anthropogenic pressures, a comprehensive understanding of species diversity, phylogenetic relationship, and the evolutionary history of wildlife is fundamental knowledge for biological conservation. The family Oxyopidae (lynx spider) is members of the superfamily Lycosoidea and represents one of the most diverse and widespread groups of cursorial spiders. They are widely distributed in various habitats such as grasslands, shrubs, and forest canopies and are also common in urban and agricultural ecosystems. The species diversity of lynx spiders in Taiwan was significantly underestimated. Therefore, this study first conducted a comprehensive taxonomic revision of Taiwanese lynx spiders and investigated their species boundaries using an integrative species delimitation approach by including morphological and molecular evidence from ABGD, ASAP, bPTP, GMYC, and BPP analyses. Based on morphological evidence, 16 species in five genera were recognized, including seven new species (Hamataliwa cordivulva sp. nov., Hamat. leporauris sp. nov., Oxyopes hasta sp. nov., O. taiwanensis sp. nov., Tapponia auriola sp. nov., T. parva sp. nov., T. rarobulbus sp. nov.) and seven newly recorded species (Hamadruas hieroglyphica (Thorell, 1887), Hamat. foveata Tang& Li, 2012, O. fujianicus Song & Zhu, 1993, O. sertatoides Xie & Kim, 1996, O. striagatus Song, 1991, O. sushilae Tikader, 1965, Peucetia latikae Tikader, 1970), while P. formosensis Kishida, 1930 was listed as a dubious species. The results showed that using a COI genetic distance (K2P) threshold of 3% can effectively delineate most species. However, the boundaries between some species are ambiguous. Oxyopes sertatus and O. taiwanensis sp. nov., as well as Hamat. cordivulva sp. nov. and Hamat.foveata, have distinct morphological differences in genitalia, but methods such as ABGD, ASAP, bPTP, and GMYC cannot distinguish them as independent species. Conversely, T. parva sp. nov. has a genetic distance greater than 4% without clear morphological differentiation. Additionally, this study reconstructed the molecular phylogeny of the lynx spider using five genetic markers (12S rRNA, 18S rRNA, 28S rRNA, COI, and histone H3) and a dataset included six genera and 42 species. Phylogenetic trees reconstructed using maximum likelihood (ML) and Bayesian inference (BI) methods support three major clades within the Oxyopidae: (1) Peucetia and Tapinillus, (2) Oxyopes, and (3) Hamadruas, Hamataliwa, and Tapponia. All genera except Tapponia are monophyletic. The relationship between Hamataliwa and Tapponia and their generic definitions require further clarification. Through geometric morphometric analysis of carapace shape indicated significant differences in carapace shape between different sexes and genera, with phylogenetic signals is presented. The analysis also explored the correlation between carapace shape variation and leg morphology with the mobile lifestyle of lynx spiders, suggesting that Oxyopidae may have originated from more mobile ancestors, characterized by wider thoracic region of carapaces and relatively longer legs, and subsequent evolution led to sedentary lifestyles, with less pronounced thoracic region and relatively shorter legs.Oxyopes sertatus, widely distributed in low-elevation mountains, farmlands, and urban green spaces in Taiwan, is an ideal species to investigate the impact of urbanization on genetic diversity. Two hypotheses have been proposed: the urban fragmentation model predicts, which predicts urbanization acts as barrier to dispersal, and the urban facilitation model, which predicts urban habitats as corridors for urban adapters. I selected 17 sites with varying degrees of urbanization in Taichung and Nantou and quantified the urbanization level using land use composition within 4 km² (landscape scale) and 0.25 km² (local scale) grids. The genetic diversity, differentiation, and population structure were assessed using COI and Restriction site associated DNA sequencing (RAD-seq) data. The results indicated a trend of decreasing genetic diversity indices with increasing urbanization level, particularly a significant reduction in observed heterozygosity (Ho) at both scales and allelic richness (Ar) at the landscape scale, although nucleotide diversity was not affected. Additionally, average genetic differentiation (FST) among populations in urban region was significantly higher than in non-urban region. These findings support the urban fragmentation model, suggesting that limited and isolated natural habitats in the city lead to small populations, increased genetic drift, and loss of genetic diversity. Nevertheless, STRUCTURE and PCA analyses did not show population genetic structure, indicating substantial gene flow between urban and non-urban populations.In conclusion, this dissertation is the first comprehensive study of diversity and phylogenetic relationships of lynx spiders, highlighting the importance of morphological diagnostics and integrative methods for accurate species diversity assessment and the significance of carapace morphology as a phylogenetic character and its implications for evolutionary adaptation of lifestyle. Finally, this study emphasizes the urgent necessity of improving the quality and connectivity of nature habitats in cities to ensure the sustainability of wildlife and urban ecosystem services and functions.
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連通性, 保育, 特有種, 地景, 形態空間, 普氏分析, connectivity, conservation, endemic species, landscape, morphospace, Procrustes analysis