A controllable dual-catapult system inspired by the biomechanics of the dragonfly larvae’s predatory strike

Abstract

The biomechanics underlying the predatory strike of dragonfly larvae is not yet understood. Dragonfly larvae are aquatic ambush predators, capturing their prey with a strongly modified extensible mouthpart. The current theory of hydraulic pressure being the driving force of the predatory strike can be refuted by our manipulation experiments and reinterpretation of former studies. Here, we report evidence for an independently loaded synchronized dual-catapult system. To power the ballistic movement of a single specialized mouthpart, two independently loaded springs simultaneously release and actuate two separate joints in a kinematic chain. Energy for the movement is stored by straining an elastic structure at each joint and, possibly, the surrounding cuticle, which is preloaded by muscle contraction. As a proof of concept, we developed a bioinspired robotic model resembling the morphology and functional principle of the extensible mouthpart. Understanding the biomechanics of the independently loaded synchronized dual-catapult system found in dragonfly larvae can be used to control the extension direction and, thereby, thrust vector of a power-modulated robotic system.

Functional morphology of the raptorial forelegs in Mantispa styriaca (Insecta: Neuroptera)

“…This catapult mechanism is proposed here for mantis lacewings for the first time. Catapult systems are well known to operate ultra-fast predatory strikes, for example in dragonfly larvae (Büsse et al 2021), or mantis shrimps (Patek et al 2004). Here, it is functioning comparable to the described catapult systems in cicadas (Gorb 2004) or trap-jaw ants (Gronenberg 1999).…”

Computational fluid dynamics provide evidence for a compensatory suction feeding like effect in the predatory strike of dragonfly larvae

“…In the larvae of damselflies and dragonflies (Insecta: Odonata), a unique prey capturing mechanism has evolved: one mouthpart, the labium, is modified into a prehensile mask (PLM) (see figure 1); capable of rapid projection for prey capturing (Corbet, 1957;Pritchard, 1965;Olesen, 1979;Büsse et al 2021). The prey spectra between larvae with these two different ecotypes of PLM differ significantly.…”

“…The PLM in general is capable of rapid protraction (Pritchard 1965;Olesen 1979;Tanaka and Hisada 1980). Powered by a dual catapult mechanism, maximum accelerations of 20g and maximum velocities of around 1 m/s have been measured (Büsse et al 2021). At high speeds, the influence of hydrodynamic forces on the movement becomes increasingly important, as substantial amounts of drag incur (Vogel 1997;McHenry et al 2016;).…”

A Tunable, Simplified Model for Biological Latch Mediated Spring Actuated Systems

“…Our approach also includes non-linear and time-dependent material properties. Additionally, we provide a generalized treatment of the latch that includes friction, allows for different latch shapes, and includes an unlatching motor that drives the latch removal of the system, similar to the one recently hypothesized to occur in some biological systems [13].…”

“…Models have been developed to understand the extreme biomechanics of latch-mediated spring actuated organisms. Organism-specific models, including both continuum mechanics-based models [2][3][4][5][6][7][8][9][10] and physical modeling with biomimetic devices [2,[10][11][12][13][14], have been used to test hypotheses about the movement of specific organisms (Table I summarizes examples of recent work).…”