The aculeate ancestry and evolution of the ants (Hymenoptera, Aculeata, Formicidae)

International audience; Ants are abundant, ecologically influential, and diverse eusocial Hymenoptera. The dominant narrative fortheir origin and radiation is that of E. O. Wilson and Bert Hölldobler, known as the “dynastic successionhypothesis”. Wilson and Hölldobler contend that the crown (= extant) ants originated during the peak of theangiosperm radiation, ~110–100 million years ago, and that post-K/Pg biodiversity recovery occurred in asequence dictated by degree of social derivation. To address this hypothesis, we reconsidered thephylogenetic scope of the problem, and generated a large morphological dataset (576 characters for 575taxa) which included extant species with ultra-conserved element (UCE) sequences and hundreds offossils. These fossils represent a comprehensive sample of Mesozoic Aculeata, Trigonaloidea,Evaniomorpha (= Evanioidea), plus the enigmatic Jurassic taxa †Bethylonymoidea and †Ephialtitoidea. Totest the geochronological prediction of the dynastic succession hypothesis, we combined the nucleotideand morphological data in a series of tip-dating analyses. To test the “scale of sociality” hypothesis, weconducted an MCMC estimation of ancestral states for all morphological characters on a distribution oftrees from our best-supported analysis, with emphasis on those traits with social-behavioral correlates.Based on the results from our two-pronged test of the Wilson- Hölldobler hypothesis, we provide areinterpretation of the origin and evolution of the ants, from the ancestor of the Aculeata to that of the crownFormicidae.