The nanoindentation technique allows researchers to perform local maps of mechanical properties, which are important to understand the mechanics of artificial and natural structures29,30,31,32,33,35,41,42. In this work, the investigation was focused on different elements of the spider’s exoskeleton for which we expect different mechanical properties: legs, prosoma, and fangs. The reason of this can be ascribed to the different cuticular structures present in these parts. Indeed, the spider cuticle is similar to the insects one that consists in various layers (exo-, meso-, and endocuticle)1,43. These are present in different proportions depending on the considered body part of the spider15, and have various level of sclerotization (i.e. mesocuticle is more sclerotized than endocuticle) and microstructural organization, two factors that both define the mechanical properties of the exoskeleton44,45,46.
In general, the reported results are aligned with previous indentation studies on spider fang’s tissue10,11,12,13,14. However, no previous work reports the comparison of mechanical properties of different body parts. This work aims to fill this gap, providing a comparison of the mechanical properties of the sclerotized layer of cuticle in the legs, prosoma, and fangs.
The prosoma exoskeleton has the main functions to shield some vital organs as well as protect the spider from quick dehydration47. Moreover, it is also the tagma responsible for locomotion, feeding, and sensing, since the prosoma’s cuticle is the base for the animal’s haemolymph pressure pump (i.e. the drive for the extension of two major joints of all of their legs and pedipalps)1,3. Legs are crucial for locomotion3 and sensing purposes since they host the major part of mechanical and chemical sensors4. On the other hand, fangs are indispensable to feed, dig, and defend the spider10. Thus, the fangs are