From the larva to the adult – morphology and material composition of the mouthparts in Odonata focusing on biomechanics and ontogeny

• Applicant: Dr. Sebastian Büsse
• Subject Area: Systematics and Morphology (Zoology)
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 264538592

Odonata (dragonflies) are important predators both as aquatic larvae and as flying adults. Their mouthparts are therefore highly specialized and adapted to the lifestyle of a predator. The DFG-funded project (BU 3169 / 1-1) is currently in detail investigating the biomechanics of larval mouthparts and first results provide fascinating insights into the interplay of 3D morphology, kinematics and material composition of the cuticle. In this follow-up project, we want to provide insights into the ontogeny and the hatching process to draw a bow to the mouthparts of the adult which are the focus of the project. This involves the morphology, material composition and properties as well as the biomechanics of the mouthparts in the context of the kinematics of the feeding process. In particular, we are interested in the degree to which the material composition of the cuticle, especially the presence of resilin, is important for the functioning of the mouthparts. Various morphological methods such as X-ray tomography, fluorescence microscopy and modern cryo-scanning electron microscopy and high-speed videography will help us understand the functional principles behind these structures. Biomechanical peculiarities such as damping, impact absorption and associated increase in wear resistance or improvements in the fatigue, which are often associated with the presence of resilin in the cuticle, are to be tested by finite element modeling approaches. In addition, a work protocol will be prepared to use the material composition in the cuticle, which we determine with fluorescence microscopy, as a template for targeted nanoindentation. Here it will be possible to localize and specifically determine material properties of the cuticle. This method will be used later to improve finite element models and increase their informative value. Further tests to determine whether the standard simplification of these models has an influence on their validity will be carried out.In its entirety, the project will provide extremely useful information for future technical applications, such as in robotics or related biomimetic fields. In addition, it allows us to gain important insights into the evolution and eco-morphology of the Odonata.

• DFG Programme: Research Grants