Mechanosensory analysis of the scolopidial distal organ in stick insects

• Applicant: Dr. Johannes Strauß
• Subject Area: Sensory and Behavioural Biology ; Cognitive, Systems and Behavioural Neurobiology
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 414216545

Animals evolved highly adapted sensory organs which detect different forms of mechanical stimuli like vibration, airborne sound, or body movements. This project investigates the distal organ in the leg of stick insects, which is a highly ordered organ consisting of linearly arranged mechanosensory scolopidial sensilla. It is part of the subgenual organ complex containing several mechanosensory organs that detect substrate vibrations and airborne sound. The elaborate feature of the sensilla in a linear organization suggests an important role in mechanoreception. The distal organ is not attached to a tendon or connective tissue strand, making a role in vibration detection likely. A model in mechanosensory physiology, stick insects allow to investigate the specific contributions from such complex organs to mechanoreception by functional and morphological approaches. The project will address (i) the linear distal organ for neuroanatomical differences over the sensilla which could indicate a functional differentiation along the organ, (ii) the evolutionary ancestral organization of the distal organ in the basal stick insect lineage by comparative neuroanatomical investigations, and (iii) the mechanical and sensory responses to mechanical stimuli transferred to the leg. These responses will be investigated by laser Doppler vibrometry and calcium imaging, to test for a place-depended response to vibration or velocity over the linear sensilla. The results will highlight the sensory adaptations for the differentiation of mechanosensory organs in insects.

• DFG Programme: Research Grants