Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning.

Mitogenomes represent useful tools for investigating the phylogeny of many metazoan clades. Regarding Collembola, the use of mitogenomics has already shown promising results, but few published works include sufficient taxon sampling to study its evolution and systematics on a broader scale. Here, we present a phylogenetic study based on the mitogenomes of 124 species from 24 subfamilies, 16 families, and four orders—one of the most comprehensive datasets used in a molecular study of Collembola evolution to date—and compare our results with the trees from recently published papers and traditional systematic hypotheses. Our main analysis supported the validity of the four orders and the clustering of Poduromorpha with Entomobryomorpha (the traditional Arthropleona). Our data also supported the split of Symphypleona s. str. into the Appendiciphora and Sminthuridida suborders, and the division of the Neelipleona into two subfamilies: Neelinae and Neelidinae subfam. nov. On the other hand, the traditional Symphypleona s. lat., Isotomoidea, and all the Isotomidae subfamilies were refuted by our analyses, indicating a need for a systematic revision of the latter family. Though our results are endorsed by many traditional and recent systematic findings, we highlight a need for additional mitogenomic data for some key taxa and the inclusion of nuclear markers to resolve some residual problematic relationships.