Between rocks and clocks: evolutionary history of Hymenoptera during the radiation of flowering plants

The order Hymenoptera encompasses ants, wasps, and bees and is a textbook example of a diverse clade, known from more than 120,000 living species, that display extraordinary morphological, taxonomic, and ecological diversity. Hymenoptera are thought to diversified synchronously to the rise of flowering plants (angiosperm) during the Angiosperm Terrestrial Revolution (ATR: 100–50 million years ago). However, despite their ecologic and economic importance – the sole honey bees yield an economic benefit for pollinating crops in the UK of over £600m each year – our understanding of their evolution remains only partially comprehended. The evolutionary history of ants, wasps, and bees is obscured by (i) unclear interrelationships among extant lineages, (ii) poor characterization of the diversity and phylogenetic affinity of fossil lineages, and (iii) outdated molecular clock analyses and methodologies. We will clarify the origins of the diversity and the timing of the co-evolution between Hymenoptera and flowering plants by combining information from the fossil record, molecular data, and the latest molecular clock dating approaches. Then, we will test the co-diversification of Hymenoptera and flowering plants as part of the ATR, which underpins much of terrestrial biodiversity, employing models that search for correlations between changes in the environment with an increase of species number during the ATR. Finally, we will use this framework for evaluating the efficacy of competing approaches to the establishment of evolutionary timescales