Data from: Diet evolution and clade richness in Hexapoda: a phylogenetic study of higher taxa

Hexapoda, the insects and their relatives, includes over half of all described species. Because large proportions of this diversity cluster within a small set of phytophagous groups, dietary-substrates have been proposed to shape patterns of richness within the clade through antagonistic co-evolution and zones of ecological opportunity. Here we explore these processes in the context of a recent dated phylogeny of Hexapod families. Our results indicate phylogenetic clustering of specialized ecologies such as phytophagy and parasitism, but reveal no consistent associations between the use of particular dietary substrates and clade richness. We also find no evidence that diets expected to promote antagonistic co-evolution are consistently associated with elevated species richness, nor that sister clades differing in dietary state are associated with greater-than-expected differences in richness. We do, however, identify variation in the age of, and transition rates among, dietary states that are likely to play a role in the observed heterogeneity in richness among dietary classes. Based on these findings we suggest remaining circumspect about the generality of adaptive zones based on broad dietary groupings as an explanation for hexapod richness, and suggest that richness heterogeneity may be better explained by origination and transitions rates, and variation within dietary categories.

六足动物（Hexapoda）涵盖昆虫及其近缘类群，包含了已描述物种总量的一半以上。由于该类群的绝大多数多样性集中于少数几个植食性演化支，已有研究提出食物基质可通过拮抗共演化与生态机遇区塑造该演化支内的物种丰富度格局。本研究依托近期发表的六足动物科水平定年分子系统发育树，对上述假说展开系统性探讨。研究结果显示，植食性、寄生等特化生态位存在显著的系统发育聚集现象，但未发现特定食物基质的使用与演化支物种丰富度之间存在一致的关联。此外，本研究未找到证据支持：预期会推动拮抗共演化的食性会持续与更高的物种丰富度相关联；亦未发现食性存在差异的姊妹演化支，其物种丰富度差异显著高于预期水平。不过，本研究确实发现不同食性状态的起源年龄与转换速率存在显著差异，这一差异或可解释不同食性类群间物种丰富度的观测异质性。基于上述发现，我们认为基于宽泛食性类群定义的适应区假说，在解释六足动物物种丰富度格局时需保持审慎；而物种丰富度的异质性或许可通过物种起源速率、食性转换速率以及食性类群内部的变异得到更好的阐释。