The use of natural fibres allows reducing environmental impact, due to their natural renewable origin and the lower energy needed for their production and processing. This work presents the mechanical characterization of a newly developed technical textile, with banana fibre treated by enzymes, comparing experimental results with numerical simulation based on the definition of the unit cell at micromechanical level. The experimental test shows that the composite with the fabric of banana fibre presents worse mechanical behaviour than the one with commercial flax fibre. The presence of wool, necessary for producing the yarn, reduces the mechanical properties of the banana textile. The numerical simulation had an acceptable error compared with the experimental results, with a global average error of 9%, showing that the predictive modelling based on the multiscale method is suitable for the design process of this kind of composite.

Biomimetic research has drawn inspiration from the knowledge acquired from the diverse morphologies and specialized functions of hymenopteran ovipositors. For example, the morphology of the honeybee stinger was used to create surgical needles that reduce insertion forces, minimize tissue damage, and increase precision. Similarly, the reciprocating drilling mechanisms observed in wood-boring hymenopterans inspired the development of steerable probes for neurosurgery, offering improved control and reduced trauma during penetration. Despite these advances, the ovipositors of sawflies, which promise intricate cutting mechanisms, have remained poorly studied in biomimetics. Unlike wood-boring species, most sawflies typically cut through soft plant tissues using their saw-like ovipositors, which could inspire new designs for precise cutting and sawing devices. This review advocates the need for further research into the structure, mechanical properties and functional principles of sawfly ovipositors to fully exploit their potential in bio-inspiration. We highlight the lack of detailed mechanical studies connecting ovipositor morphology to cutting efficiency and substrate interactions. Understanding these relationships could uncover new principles for engineering applications, such as medical or industrial cutting tools.

The female sawfly (Insecta: Hymenoptera, Symphyta) uses a double blade reciprocating saw-like ovipositor to cut into plant tissue and lay its eggs within the cut. Whereas extensive study was carried out for wood-boring ovipositors, little is known about how sawflies achieve such controlled cutting in soft substrates. This suggests a mechanism that balances effective cutting with minimal tissue disruption. This article reports a novel passive selective cutting mechanism in which the saw discriminates between material properties of the plant tissue without active sensing or external control, something rarely achieved in human-made systems. Scaled-up biomimetic blades replicating key ovipositor features were tested on synthetic substrates (agar and ballistic gelatine) across a range of stiffnesses. Experimental results reveal a force-dependent threshold above which the saw is displaced rather than cutting. This threshold depends on the interaction between the shape of the saw teeth and the substrate properties and is consistent across multiple sawfly species. These findings reveal a previously undescribed bioinspired cutting principle with potential for surgical tools that avoid damaging sensitive tissues, and broader applications where passive, material-specific selectivity is required without the complexity of sensors or active feedback control.

The female sawfly (Insecta: Hymenoptera, Symphyta) uses a double reciprocating saw-like ovipositor to cut into plant tissue, laying its eggs within the cut. We have identified a passive selective cutting mechanism in which the saw discriminates between material properties of the plant tissue without active sensing or external control. The mechanism balances effective cutting with minimal collateral damage to either the plant or the saw. Scaled-up models of the saw cutting into experimental substrates (agar and ballistic gelatine) across a range of stiffnesses reveal an ultimate stress threshold above which substrates are displaced rather than incised. This depends on the interaction between the shape of the saw teeth and the substrate properties and is consistent across multiple species of sawfly. These findings suggest a novel surgical tool design with high selectivity of cutting and reduced collateral damage.

Sawflies (Insecta: Symphyta) use their ovipositors to incise plant tissue and deposit eggs, a task that demands precise substrate discrimination while preserving both ovipositor and host. How a passive selective mechanical system such as the ovipositor can discriminate between substrates based on material properties without active sensing or control remained until now an open question. This article presents an analytical model of the selective cutting mechanism inspired by sawfly ovipositors. Substrate cutting is shown to depend on an ultimate stress threshold determined by the interaction between blade geometry and substrate properties. The model captures the transition between cutting and ejection as a competition between a failure and an ejection criterion. Morphological modifiers, including serrulae and banding patterns, are shown to influence the ultimate stress threshold and are strongly dependent on both substrate hardness and elastic modulus. The model explains key previously reported observations obtained from prior experimental work that used scaled up biomimetic blades. These findings suggest novel directions in the design of surgical tools required to cut heterogeneous tissues with minimal extraneous damage.