"Neuro-molecular graviception mechanisms: From sensory organs to behavioral actions in holometabolous insects"

Abstract :

"Gravity perception is a main vector for spatial orientation in many species. In some pest insects, such as the European corn borer (O. nubilalis), a recent adaptation involving positive geotaxis allows larvae to survive mechanized harvesting, leading to significant economic losses. However, how developing larva or caterpillar sense gravity to display geotactic behaviors is completely unknown.  This project aims to elucidate the mechanisms of graviception using the Drosophila melanogaster larva as a reference model.

Using a 2D clinostat and high-resolution behavioral tracking, my work has characterized a specific graviceptive behavior at the pre-pupal stage. Through targeted genetic screenings, I identified chordotonal organs as the neuronal basis of this response and demonstrated that the mechanosensory genes nompc and piezo are fundamental to graviception. Circuit decoding reveals a functional specialization in the integration of sensory signals, mediated by Basin 1/2 neurons, translates spatial orientation into distinct motor programs, "hunching" or "turning", depending on the animal's position.

We built a mathematical model to simulate the translation of neural activity into behavioral actions. This "neurons-to-actions" model was validated through precise genetic manipulations, confirming the robustness of the proposed spatial perception framework."