Paleodiversity of Paleogene hymenopteran insects and their interactions with flowers

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Both today and in the past insects play crucial roles in terrestrial ecosystems and exhibit remarkable biodiversity, yet they remain understudied. Especially the mega-diverse hymenopteran insects play major roles in plant-insect interactions and pollination biology. This project aims to investigate the evolution of insect-flower interactions and the paleoecology of selected groups of hymenopteran insects by using direct paleontological evidence from the Paleogene in comparison to the present day. The paleobiodiversity of fossil hymenopterans will be investigated in close comparison to extant taxa. By analyzing in-situ pollen grains preserved on or in the bodies of these insects, the project aims to infer the ecological roles of different hymenopteran families and genera and identify the plant groups they visited. Insights into foraging behavior, feeding behavior, and pollination biology will contribute to our understanding of the evolution of flower-insect interactions over geological time. Hymenopteran insects are especially suited for our planned investigations due to their complex ecological interactions with flowering plants. The research will focus on the Fossillagerstätten Messel and Enspel (both located in Germany), which offer insights into the Eocene and Oligocene periods, respectively. These time windows will be compared with the present day, providing a timeline for analysis. The Eocene is of special interest, because with its elevated CO2-level and globally warm climate, it may serve as an analog for our future climate. Both Messel and Enspel have yielded numerous excellent preserved hymenopteran fossils, and exquisitely preserved in-situ pollen grains can be extracted from those fossils. Innovative methods will be employed to reliably identify the fossil pollen, classifying them with extant plant families and genera. Conclusions on different ecological aspects of foraging of pollen and pollination will be possible. These findings will enrich the fossil record of the studied groups and widen the knowledge on paleoecology. The analyses will be done in close comparison to extant taxa of both hymenopteran insects and flowering plants, providing opportunities for investigating the evolution of these groups in regard to the current climate change. Application of community ecology and network analysis approaches can provide unique insights into the former interactions of hymenopteran insects with flowering plants and how this compares to modern ecosystems.