A striking difference: biomechanics of the impaling hunting strategy of a moss mantis

BACKGROUND: Biological catapults as power amplification systems are widespread across diverse taxa, known for their evolutionary significance and effectiveness in various ecological contexts. Although praying mantises are renowned for their predatory behavior, typically involving a directly muscle-driven, grasping-like motion to capture prey, a strongly altered movement sequence is observed in Haania orlovi. The moss mantis exhibits a spear-like foreleg morphology and a significantly different ultrafast impaling hunting strategy. RESULTS: This system generates a mass-specific power output, surpassing the limits of direct muscle contraction. Through comprehensive morphological analysis (micro-computed tomography, scanning electron microscopy), combined with high-speed videography and force measurements, we provide evidence for a latch-mediated spring actuation (LaMSA) system, enabling this ballistic motion. The mechanism involves elastic energy storage in the deformed cuticle of the proximal trochanter, supported by latch-like interlocking. Confocal laser scanning microscopy revealed specialized cuticle composition in the trochanter, facilitating energy storage. For further validation, we developed a 3D-printed proof-of-concept model, incorporating a deformable spring-like double-spiral structure, demonstrating the functional advantage of the LaMSA system in generating high-speed movements. CONCLUSION: This study not only elucidates a novel predatory mechanism in mantises but also contributes to our understanding of evolutionary adaptations in predator-prey interactions. Illustrating the essential mechanical components in a physical model, and the compact, load-responsive dual functionality of the described power amplification system, potentially serves as inspiration for advancements in bio-inspired engineering solutions. Our findings highlight the importance of integrated biomechanical analysis in uncovering novel biomechanical mechanisms, demonstrating potential for significant functional shifts through seemingly minor morphological modifications.