Data from: Evolution of stenophagy in spiders (Araneae): evidence based on the comparative analysis of spider diets

Stenophagy (narrow diet breadth) represents an extreme of trophic specialization in carnivores, but little is known about the forces driving its evolution. We used spiders, the most diversified group of terrestrial predators, to investigate whether stenophagy 1) promoted diversification, 2) was phylogenetically conserved and evolutionarily derived state, and 3) was determined either by geographical distribution and foraging guild. We utilized published data on the prey of almost 600 species. Six categories of stenophagy were found: myrmecophagy, araneophagy, lepidopterophagy, termitophagy, dipterophagy and crustaceophagy. We found that the species diversity of euryphagous genera and families was similar to stenophagous genera and families. At the family level, stenophagy evolved repeatedly and independently. Within families, the basal condition was oligophagy or euryphagy. Most types of stenophagy were clearly derived: myrmecophagy in Zodariidae; lepidopterophagy in Araneidae; dipterophagy in Theridiidae. In contrast, araneophagy was confined to basal and intermediate lineages, suggesting its ancestral condition. The diet breadth of species from the tropics and subtropics was less diverse than species from the temperate zone. Diet breadth was lower in cursorial spiders compared to web-building species. Thus, the evolution of stenophagy in spiders appears to be complex and governed by phylogeny as well as by ecological determinants.

狭食性（Stenophagy，即狭窄的食谱宽度）代表了食肉动物营养特化的极端形式，但目前学界对驱动其演化的核心机制仍知之甚少。本研究以陆生捕食者中物种多样性最高的类群——蜘蛛为研究对象，旨在探究狭食性是否具备以下三项特征：1） 可推动物种分化；2） 具有系统发育保守性且属于演化衍生状态；3） 由地理分布与觅食功能群（foraging guild）所决定。研究团队利用了近600个蜘蛛物种的猎物相关已发表数据，共识别出六类狭食性：蚁专食性（myrmecophagy）、蛛专食性（araneophagy）、鳞翅目专食性（lepidopterophagy）、白蚁专食性（termitophagy）、双翅目专食性（dipterophagy）以及甲壳类专食性（crustaceophagy）。研究发现，广食性属与科的物种多样性与狭食性类群并无显著差异。在科的分类水平上，狭食性多次独立演化产生。在各科内部，祖先营养策略多为寡食性或广食性。多数狭食性类型均为明确的衍生状态：佐达蛛科（Zodariidae）的蚁专食性、园蛛科（Araneidae）的鳞翅目专食性以及球蛛科（Theridiidae）的双翅目专食性。与之相对，蛛专食性多局限于基部与中间演化支，提示该类型为祖先营养策略。热带与亚热带物种的食谱宽度多样性显著低于温带物种。游猎型蜘蛛的食谱宽度相较于结网型蜘蛛更低。综上，蜘蛛狭食性的演化过程较为复杂，同时受系统发育与生态决定因素共同调控。