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Phylogenomics and macroevolution of Calosoma beetles (Coleoptera, Carabidae, Carabinae)

Author Cody CARDENAS
Director of thesis Dr. Emmanuel Toussaint (Musume d'Historie Naturalle Geneve)
Co-director of thesis Dr. Evgeny Zdobnov (UniGe Faculty de Medecine)
Summary of thesis

The evolution of flight allowed for the diversification of insect lineages nearly 400 million years ago. This adaptation allowed numerous lineages to disperse, radiate, and diversify into the flying insects we recognize today. However, numerous lineages have since lost their flight capability, and many flightless species have been observed in extreme and isolated habitats like islands and mountain ecosystems. Because of this reoccurring pattern, many hypotheses about the evolutionary forces driving flight loss have been proposed. A widely accept driver of flight loss in insects is the adaptation to persistent and stable habitats. Yet, how flightlessness evolved and its impact on the course of evolution is largely unclear. To address this knowledge gap, I will study the evolution of flight in the ground beetle genus Calosoma (Coleoptera, Carabidae, Carabinae). This genus is ideal to study the evolution of flight because it is found worldwide, including relatively extreme habitats. While there is some disagreement about the taxonomic relationships of lineages within Calosoma, their wing morphology is comparatively well documented. Nearly half of Calosoma species are flight capable (macropterous) and while the rest present degrees of flightlessness (micropterous to brachypterous). Given the limited knowledge of the phylogenetic relationships within the genus, my overarching goal is to reconstruct a complete phylogeny of Calosoma using ultra-conserved elements (UCE). This work will allow me to re-examine the systematics of the genus, interpret the biogeographic and reveal the evolutionary history of Calosoma beetles. In addition to studying the macro-evolution of Calosoma I will investigate the phylogeography of two geographically localized lineages in Calosoma. Both are flightless and restricted to alpine habitats, one in the Balkans and the other Ethiopia. Studying these two lineages will allow for comparative phylogeographic analyses of the micro-evolutionary consequences of flightlessness. In addition I also aim to investigate how how flight capability drives natural selection on intracellular organelles mitochondria using sequencing by-catch. Lastly, I will use x-ray micro computed tomography to integrate endoskeletal morphology (cuticles and muscle attachments) in my phylogenetic analyses to explore wing morphology evolution in Calosoma. Through my thesis work, I will expand our knowledge on how the evolution of flight might impact the evolutionary history of insect lineages

Status beginning
Administrative delay for the defence 2025/2026