title: Musculoskeletal modelling of the dragonfly mandible system as an aid to understanding the role of single muscles in an evolutionary context.
abstract: Insects show a great variety of mouthpart and muscle configurations; however, knowledge of their mouthpart kinematics and muscle activation patterns is fragmentary. Understanding the role of muscle groups during movement and comparing them between insect groups could yield insights into evolutionary patterns and functional constraints. Here, we developed a mathematical inverse dynamic model including distinct muscles for an insect head-mandible-muscle complex based on micro-computed tomography (µCT) data and bite force measurements. With the advent of µCT, it is now possible to obtain precise spatial information about muscle attachment areas and head capsule construction in insects. Our model shows a distinct activation pattern for certain fibre groups potentially related to a geometry-dependent optimization. Muscle activation patterns suggest that intramandibular muscles play a minor role in bite force generation, which is a potential reason for their loss in several lineages of higher insects. Our model is in agreement with previous studies investigating fast and slow muscle fibres and is able to resolve the spatio-temporal activation patterns of these different muscle types in insects. The model used here has a high potential for large-scale comparative analyses on the role of different muscle setups and head capsule designs in the megadiverse insects in order to aid our understanding of insect head capsule and mouthpart evolution under mechanical constraints.
authors.affiliation: Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne 50933, Germany.
authors.forename: Sina
authors.initials: S
authors.lastname: David
authors.affiliation: Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne 50933, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Funken
authors.affiliation: Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne 50933, Germany ARCUS Clinics Pforzheim, Rastatter Strasse 17-19, Pforzheim 75179, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Potthast
authors.affiliation: Medical and Biological Engineering Research Group, School of Engineering, University of Hull, Hull HU6 7RX, UK a.blanke@hull.ac.uk.
authors.forename: Alexander
authors.initials: A
authors.lastname: Blanke
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001732:Bite Force; D008334:Mandible / Q000502:physiology*; D008954:Models, Biological; D009055:Mouth / Q000502:physiology*; D009068:Movement / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D063191:Odonata / Q000502:physiology*; D055114:X-Ray Microtomography
keywords: Bite force; Insects; Inverse dynamics; Multibody dynamics analysis; Muscle activation; Odonata