Résumé
Understanding the origins and macroevolutionary trajectories of lineages is central in evolutionary biology. The insect order Hymenoptera encompasses over 117,000 extant species, comprising ants, bees, wasps, and sawflies, and has a rich fossil record. They likely played a pivotal role in the mid-Mesozoic parasitoid revolution (MMPR), reshaping terrestrial food webs, and in the Angiosperm Terrestrial Revolution (ATR), by forming complex interactions with flowering plants (e.g., pollination). However, the lack of estimates for the origin and rise of many extant and extinct families within Hymenoptera impedes a comprehensive understanding of their contribution to the MMPR and the impact of the ATR on their past diversity dynamics. This presentation underscores the significance of fossil information for understanding evolutionary trajectories, particularly in the context of the MMPR and the ATR. Leveraging an unprecedented dataset of fossil occurrences and state-of-the-art Bayesian modelling approaches, we estimate the origin of all extinct and extant hymenopteran lineages and the timing of the extinction of fossil lineages. Our approach offers an alternative to traditional approaches relying on time-calibrated phylogenies and molecular clocks, which face challenges when dealing with old lineages having an abundant fossil record but few or no extant representatives. Additionally, we explore the contribution of Hymenoptera to the MMPR and show that most extinct and extant parasitoid lineages originated between the Early Jurassic and the Late Cretaceous. We also demonstrate that many Mesozoic hymenopteran lineages declined or went extinct during or slightly before the ATR, which suggests that the environmental changes triggered by the diversification of flowering plants profoundly reshaped the ecosystems leading to the extinction of many Mesozoic lineages. Oppositely, the ATR is also concomitant with the diversification of major hymenopteran lineages such as the parasitoid Chalcidoidea and the Apoidea. These lineages are known to directly feed on nectar or pollen produced by flowering plants (e.g., Apidae), predate preys consuming angiosperms or parasitize other insects thriving on flowering plants (e.g., Chalcididae). Together, these results demonstrate that the ATR played a dual role in triggering the decline of certain insect lineages and the diversification of others. This presentation aims to bridge existing gaps, offering new insights into the timing and past dynamics of Hymenoptera evolution, particularly their pivotal role in the mid-Mesozoic parasitoid revolution, and the Angiosperm Terrestrial Revolution.