revisiting niche divergence hypothesis in dimorphic birds: is diet overlap correlated with sexual size dimorphism?

The evolution of sexual size dimorphism (SSD) is a long-standing topic in evolutionary biology, but there is little agreement on the extent to which SSD is driven by the different selective forces. While sexual selection and fecundity selection have traditionally been proposed as the two leading hypotheses, SSD may also result from natural selection through mechanisms such as sexual niche divergence, which might have reduced resource competition between sexes. Here, we revisited the niche divergence hypothesis by testing the relationship between the sexual overlap in diet and SSD of 56 bird species using phylogenetic comparative analyses. We then assessed how SSD variation relates to the three main hypotheses: sexual selection, fecundity selection, and sexual niche divergence using phylogenetic generalized least squares (PGLS). Then, we compared sexual selection, fecundity selection, and niche divergence selection as SSD drivers through phylogenetic confirmatory path analyses to disenta..., The database of diet overlap was compiled through a literature survey of all major ornithological journals. The ISI Web of Knowledge was systematically searched for original case studies in which data on the diet composition of males and females were provided. A total of 289 references were examined, 62 of which provided data on the diet of both sexes for 58 species belonging to 32 families. We discarded studies based on prey types brought to the nest by adults (n=8) because food provisioning to chicks does not represent the actual nutritional requirements of males and females, or those based on isotope analyses (n=10), since both sexes might show overlapping isotopic niches, while having a different trophic niche, for instance, if both sexes feed on different prey with similar δ15N values (Bearhop et al., 2004). Diet composition was described using stomachs, esophageal contents, and regurgitations (80.3% of the studies), feces (13.1%), and direct observation (6.6%). The description of ..., , # Revisiting niche divergence hypothesis in sexually dimorphic birds: is diet overlap correlated with sexual size dimorphism? This study explores the relationship between Sexual Size Dimorphism (SSD) and ecological dynamics in bird species. The dataset includes information on the diet of 58 bird species, aiming to investigate the correlation between SSD and diet overlap, mating systems, sexual display behaviors, and clutch size. \**Dataset contents: ** We compiled data from a thorough literature survey, sifting through 289 references to focus on 58 bird species. The dataset includes details on diet overlapping between both males and females. Mating systems were categorized, incorporating polyandry, monogamy, and polygyny. Male sexual display behaviors were classified based on a five-point scale, ranging from ground displays to acrobatic aerial displays. Clutch size, representing fecundity, was also documented. Morphometric traits, such as body mass, wing length, bill length, and tar...性体型二态性（sexual size dimorphism, SSD）的演化是进化生物学领域的长期经典议题，但学界对于不同选择压力驱动SSD形成的程度尚未达成共识。传统上，性选择与繁殖力选择被视为解释SSD的两大主流假说，而SSD也可能通过性生态位分化等自然选择机制产生——这类机制可降低两性间的资源竞争。本研究重新审视了性生态位分化假说，通过系统发育比较分析，检验了56种鸟类的食性重叠程度与SSD之间的关联。随后，我们采用系统发育广义最小二乘（phylogenetic generalized least squares, PGLS）方法，分析了SSD变异与三大主流假说（性选择、繁殖力选择、性生态位分化）的相关性。此外，我们还通过系统发育验证路径分析，比较了性选择、繁殖力选择与生态位分化选择作为SSD驱动因子的相对重要性，以厘清其作用机制…… 本研究的食性重叠数据库通过对所有主流鸟类学期刊的文献调研构建完成。我们系统性检索了ISI Web of Knowledge，以获取包含雌雄两性食性组成数据的原创性案例研究。最终共核查了289篇参考文献，其中62篇提供了隶属于32个科的58个物种的两性食性数据。我们剔除了两类研究：一类是基于成鸟带回巢的猎物类型的研究（n=8），因为育雏投喂的食物无法反映雌雄个体实际的营养需求；另一类是基于同位素分析的研究（n=10），因为两性的同位素生态位可能存在重叠，但营养生态位却存在差异——例如，当两性取食δ¹⁵N值相似的不同猎物时，就会出现这种情况（Bearhop等，2004）。本研究的食性组成数据来源于以下几种方式：胃容物、食道内容物与反刍物（占总研究的80.3%）、粪便（13.1%）以及直接观察（6.6%）。 # 重新审视性二态性鸟类的生态位分化假说：食性重叠与性体型二态性是否相关？ 本研究探讨了鸟类性体型二态性（SSD）与生态动态之间的关联。本数据集涵盖58种鸟类的食性信息，旨在探究SSD与食性重叠、交配系统、雄性求偶展示行为以及窝卵数之间的相关性。 **数据集内容：** 我们通过全面的文献调研整合数据，筛选了289篇参考文献，最终聚焦于58种鸟类。数据集包含两性食性重叠的详细信息。交配系统被划分为一雌多雄制（polyandry）、单配制（monogamy）与一雄多雌制（polygyny）。雄性求偶展示行为根据从地面展示到杂技式空中展示的五点量表进行分类。反映繁殖力的窝卵数也被记录在册。此外，数据集还涵盖了体型形态性状数据，如体重、翼长、喙长以及跗跖（原文此处内容截断）……