基于形态、行为和分子数据的球蛛科（蛛形纲：蜘蛛目）系统发育学研究

Cobweb spiders (Theridiidae) are highly diverse from the perspective of species richness, morphological diversity, variety of web architecture, and behavioral repertoires. The family includes over 50% of social spiders, a behavioral rarity among the order, and members of the family are furthermore the subject of research on venom, silk biomechanics, kleptoparasitism and web building, among other traits. Theridiidae is one of the most abundant groups of spiders, and thus key insect predators in many different ecosystems and is among relatively few spider families that show high degree of myrmecophagy. Modern comparative studies on all these fronts are best buttressed on a phylogenetic foundation. Our goal of this proposed project is to offer a revised, dated, phylogenetic hypothesis for the family by summarizing previously published data from multiple molecular and morphological studies which were carried out by applicant as a visiting scholar in Ingi Agnarsson’s lab during 2014-2015, and adding novel data from China. We shall make collection of specimens from various sources including our lab, other domestic and foreign labs and the field collections in the future, and carry out a systematic taxonomy research on Chinese Theridiidae based morphological, behavioral, and DNA data. We plan to do our research from the following four aspects: (1) we will present the classical morphological taxonomy research on Chinese Theridiidae; (2) we will analyze the morphological and behavioral characteristics of Theridiidae; (3) we will amplify and sequence six gene fragments for every species including two mitochondrial: the large-subunit ribosomal RNA (16S rRNA, hereafter 16S) and the protein-coding cytochrome c oxidase subunit I (COI); and four nuclear: the protein-coding histone H3 (H3), the large-subunit ribosomal RNA (28S rRNA, hereafter 28S), the nearly complete small-subunit ribosomal RNA (18S rRNA, hereafter 18S), and the internal transcribed spacer 2 (ITS2); (4) we will combine sequence data from six genes with a morphological and behavioral dataset in a total-evidence phylogenetic analysis, and explore the phylogenetic signal of the combined dataset, morphology, individual genes, and gene combinations with different parsimony methods and model-based approaches. The results from this study will not only enhance our understanding of the origin, evolution and phylogenetic relationships of Chinese Theridiidae but also shed lights on the scientific issues of world Theridiidae such as the issue of subfamily classification systems of this family.

球蛛科蜘蛛种类多，数量大，是多种生态系统中重要的捕食者。同时，该科部分种类具有盗寄生、专性捕食蚂蚁、形成交配栓、营社会性等特殊行为，也是研究蛛丝、蛛毒的重要材料。上述研究热点均迫切需要一个科学的球蛛科系统发育关系做支撑。中国球蛛科资源丰富，是世界球蛛科的重要组成部分。本项目拟在申请者前期国外访学期间研究世界球蛛科系统发育关系的基础上，广泛收集中国球蛛科标本，提取其形态、行为和分子数据，重建世界球蛛科系统发育关系。项目共分四部分：（1）球蛛科经典分类；（2）球蛛科形态、行为特征提取；（3）球蛛科物种多个基因片段的扩增与测序；（4）基于形态、行为与分子数据构建世界球蛛科精准系统发育树，重建世界球蛛科分类系统。本课题的研究结果不仅有助于摸清中国球蛛科家底，理清中国球蛛科种上阶元的起源、进化和系统发育关系，更为世界球蛛科种上阶元进化中一系列广泛存在争议的重要科学问题提供新的，具有较高可信度的证据。

球蛛科蜘蛛种类多，数量大，是多种生态系统中重要的捕食者。该科部分种类具有盗寄生、专性捕食蚂蚁等特殊行为，也是研究蛛网可塑性的重要材料。中国球蛛科资源丰富，是世界球蛛科的重要组成部分。本项目在广泛收集中国球蛛科标本基础上开展以下四方面研究：（1）经典分类学：完成200余种中国球蛛的显微拍摄及描述，包括新种60余种；（2）分子系统学：支持世界球蛛科7亚科系统，支持编织杂质庇护所类群的单系性，拒绝球蛛亚科球蛛属Theridion, Platnickina, Parasteatoda等属的单系性，支持钟蛛属Campanicola的单系性，但编织铃形杂质庇护所的四个属Achaearanea, Cryptachaea, Parasteatoda和Campanicola并未聚到一起；分子钟和祖先特征重建显示球蛛科蜘蛛祖先大概在22.66 Ma开始编织精致的铃形杂质庇护所，而此时正是地球气温急剧降低期间，此后22.61 Ma 到15.16 Ma期间，球蛛祖先开始转换编织简单的枯叶状庇护所，而此时正是地球气温急剧波动上升期间，而自15.16 Ma至今，球蛛祖先则一直是编织精致的复杂的铃形杂质庇护所，则地球的气温一直是急剧降低，故推测球蛛科编织杂质庇护所行为与地球气温的剧烈波动显著相关，而铃形杂质庇护所的主要功能很有可能与球蛛祖先为了卵袋、育幼保温等功能相关。3）球蛛结网行为学：以铃形钟蛛的蛛网为研究对象，提供一种新的蛛网可塑性研究模型，结果发现铃形钟蛛在生长发育过程中存在明显的能量权衡－雌蛛在生长发育过程中投入越来越多的能量用于防守而雄蛛则投入越来越多的能量用于繁殖。（4）球蛛肠道微生物组学：利用两种不同种类的蚂蚁饲喂铃形钟蛛，探讨不同猎物营养水平及其肠道微生物群落对球蛛肠道微生物群落多样性的影响，结果发现猎物的蛋白质、糖类水平、肠道微生物群落等差异并不影响球蛛肠道微生物群落多样性。本课题的研究结果不仅有助于摸清中国球蛛科家底，理清世界球蛛科种上阶元的系统发育关系，更为蜘蛛结网行为学研究提供一个新的模型和研究框架。