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Item-typ:Veröffentlichung, Effect of mechanical stress on insect exoskeleton(2022-09-27); ; ; A typical feature of many biological materials is their ability to adapt to mechanical load. Bone remodeling for example is stimulated by deformation, trees can react to increased load by formation of compression or tension wood. This ability allows for efficient investment of building material, as it is only deposited when biomechanically needed. However, it is still not known whether cuticle exoskeletons of insects, one of the most common biological materials, also show the ability to remodel under increased mechanical load. To investigate the hypothesis, that the insect exoskeleton, as a biological material, reacts to long-term increased mechanical load, four studies were conducted:1) How to measure insect cuticle biomechanical properties? 2) How can cuticle morphology be visualized in high detail? 3) If and how does insect cuticle react to long term applied mechanical load? 4) If and how does insect exoskeleton react under mechanical and light induced stress? Results show direct experimental evidence that increased mechanical load affects the biomechanical properties of an insect exoskeleton for the first time. The exo- and endocuticle were visualized using a novel staining method for high-resolution X-ray microtomography. Comprehensive biomechanical measurements show that up to 3g load the Young’s modulus and bending strength of cuticle increase. Higher gravitational loads, however, decreased insect survival rate and body mass and endocuticle thickness. These findings are not only a starting point for fundamental questions regarding the proximate mechanisms behind this ability of cuticle exoskeletons; however, also add important context to the discussion on general ultimate factors in the evolution of adaptive biological materials.Dissertation325 439 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Biomechanics of insect cuticle: an interdisciplinary experimental challengeThe cuticle exoskeleton plays a key role in facilitating the evolutionary success of insects. Since the mid of the last century, many different biomechanical properties of exoskeletons have been investigated, always utilizing the most sophisticated scientific methods available at the time. So far, information on the biomechanical properties of cuticle seems to be as diverse as the methods used to measure them. As a consequence, insect cuticle is often considered to exhibit the most complex and diverse biomechanical properties of any biological material. However, it remains unclear which role the respective measurement methods and sample treatments used in previous studies play in supporting this claim. This review provides a broad overview of examination techniques used to study biomechanical properties of insect exoskeletons and discusses their respective advantages and disadvantages in describing the properties of a complex material such as cuticle. Our meta-analysis of the present data confirms significant effects of the respective measurement methods, sample treatments and body parts on the obtained mechanical properties. Based on our findings, we highlight research gaps and point out important factors which should be taken into account in future studies on insect cuticle.Wissenschaftlicher ArtikelBand:127Heft:5178 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Insect exoskeletons react to hypergravityA typical feature of biological materials is their ability to adapt to mechanical load. However, it is not known whether the cuticle exoskeleton, one of the most common biological structures, also shares this trait. Here, we show direct experimental evidence that prolonged exposure to hypergravity conditions affects the morphology and biomechanics of an insect exoskeleton. Locusts were raised for several weeks in a custom-designed centrifuge at various levels of hypergravity. Biomechanical measurements and X-ray microtomography show that up to 3g load the Young’s modulus of the tibiae increased by about 67\%. Higher gravitational loads however decreased the survival rate, body mass and endocuticle thickness. These results directly show that cuticle exoskeletons can react to hypergravity. This ability has so far only been known for bone endoskeletons and plants. Our findings thus add important context to the discussion on general ultimate factors in the evolution of adaptive biological materials and skeletal systems.Wissenschaftlicher Artikel387 222 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Semi-automated differentiation of insect exo- and endocuticle in X-ray microtomographyOne of the most versatile and complex biological composite materials, the insect exoskeleton shows a huge range in biomechanical properties. The cuticle exoskeleton can be differentiated into two main histologically different layers with distinct properties: the outer, more sclerotized exocuticle and inner, softer endocuticle. For most biomechanical research questions, it is of great importance to be able to selectively characterize geometrical features of these layers. However, most conventional preparation methods (cross-sections, histological staining, SEM) require complex and destructive sample preparation, which provides only two-dimensional information. Here, we present a novel, simple staining method using X-ray microtomography to distinguish between exo- and endocuticle in a 3D environment without sample destruction. We illustrate the power of our method using locust (Locusta migratoria) hindleg tibia, a well characterized biomechanical sample. Our method allows an easy and direct measurement of exo- and endocuticle and their respective geometric features. Applying our method will help to understand the biomechanical role of exo- and endocuticle within an insect exoskeleton and will allow us to understand its composition and morphological features in more detail.Wissenschaftlicher ArtikelBand:66177