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On a global scale, biodiversity is geographically structured into regions of biotic similarity. Delineating these regions has been mostly targeted for tetrapods and plants, but those for hyperdiverse groups such as insects are relatively unknown. Insects may have higher biogeographic congruence with plants than tetrapods due to their tight ecological and evolutionary links with the former, but it remains untested. Here, we develop a global regionalization for a major and widespread insect group, ants, based on the most comprehensive distributional and phylogenetic information to date, and examine its similarity to regionalizations for tetrapods and vascular plants. Our ant regionalization supports the newly proposed Madagascan and Sino-Japanese realms based on tetrapod delineations, and it recovers clusters observed in plants but not in tetrapods, such as the Holarctic and Indo-Pacific realms. Quantitative comparison suggests strong associations among different groups-plants showed a higher congruence with ants than with tetrapods. These results underscore the wide congruence of diverse distribution patterns across the tree of life and the similarities shared by insects and plants that are not captured by tetrapod groups. Our analysis highlights the importance of developing global biogeographic maps for insect groups to obtain a more comprehensive geographic picture of life on Earth., (© 2024. The Author(s).)

Species delimitation offered by DNA-based approaches can provide important insights into the natural history and diversity of species, but the cogency of such processes is limited without multigene phylogenies. Recent attempts to barcode various Solenopsidini ant taxa (Hymenoptera: Formicidae: Myrmicinae), including the thief ant Solenopsis saudiensis Sharaf & Aldawood, 2011 described from the Kingdom of Saudi Arabia (KSA), were precipitated by the unexpected existence of a closely related species, the Nearctic S. abdita Thompson, 1989 within the S. molesta species complex native to Florida. This finding left the species status of the former uncertain. Here, we investigated the taxonomy and phylogeny of these two species to determine whether or not S. abdita represents a new global tramp species. We inferred a phylogeny of the two species using DNA sequence data from four nuclear genes (Abd-A, EF1α-F1, EF1α-F2, and Wingless) and one mitochondrial gene (COI) sampled from populations in Florida, Guatemala, Hawaii, and Saudi Arabia. Both species clustered into one distinct and robust clade. The taxonomy of S. saudiensis was re-examined using morphometrics. A reassessment of the morphological characters used to diagnose the worker and queen castes were consistent with molecular evidence. Based on combined morphological and molecular evidences S. saudiensis is declared as a junior synonym of S. abdita (syn. nov.). In addition, our findings indicate that S. abdita is a novel global tramp species which has a far wider distribution than previously thought and has established itself in many new habitats and different geographic realms.

Adaptive radiations are of particular interest owing to what they reveal about the ecological and evolutionary regulation of biodiversity. This applies to localized island radiations such as Darwin's finches, and also to rapid radiations occurring on a global scale. Here we analyse the macroevolution and macroecology of Pheidole, a famously hyperdiverse and ecologically dominant ant genus. We generate and analyse four novel datasets: (i) a robust global phylogeny including 285 Pheidole species, (ii) a global database on regional Pheidole richness in 365 political areas summarizing over 97 000 individual records from more than 6500 studies, (iii) a global database of Pheidole richness from 3796 local communities and (iv) a database of Pheidole body sizes across species. Analysis of the potential climate drivers of richness revealed that the patterns are statistically very similar across different biogeographic regions, with both regional and local richness associated with the same coefficients of temperature and precipitation. This similarity occurs even though phylogenetic analysis shows that Pheidole reached dominance in communities through serial localized radiations into different biomes within different continents and islands. Pheidole body size distributions have likewise converged across geographical regions. We propose these cases of convergence indicate that the global radiation of Pheidole is structured by deterministic factors regulating diversification and diversity.