Skip to content

Using Particle Image Velocimetry (PIV) to Understand Marine Life.

Metachronal Swimming of Mantis Shrimp

Mantis shrimp boast an impressive swimming technique called metachronal rowing. This involves their five pairs of pleopods (swimming appendages) on their abdomen moving in a sequential, wave-like motion.

How it works:

Power Stroke: The posterior (rearmost) pair of pleopods initiates the power stroke, pushing water backward and propelling the animal forward.
Recovery Stroke: As the posterior pleopods complete their power stroke, the anterior (frontmost) pleopods begin their recovery stroke, moving forward in a more synchronized manner. This creates a wave of thrust that propels the mantis shrimp forward.
Wave Propagation: This wave of thrust continues along the mantis shrimp’s body as each pair of pleopods completes its power stroke and then transitions to the recovery stroke as seen in the high speed imaging sequence to the right.

Benefits of Metachronal Swimming:

High Efficiency: This swimming method allows mantis shrimp to achieve remarkable swimming speeds, reaching up to 2 meters per second in short bursts.
Maneuverability: The sequential movement of their pleopods allows for precise control of their direction and movement, enabling them to quickly change direction and capture prey.
Energy Conservation: Metachronal swimming is a highly efficient way to generate thrust, allowing mantis shrimp to conserve energy for other activities like hunting and burrowing.

The beat frequency of their pleopods can range from 3 to 13 Hz, depending on the speed and agility required. The stroke angle of their pleopods also plays a crucial role in generating thrust. Larger stroke angles lead to faster swimming speeds. Recent studies have identified vortex interactions between the pleopods that contribute to increased thrust and efficiency (see published work listed to the right).  Overall, the metachronal swimming of mantis shrimp is a fascinating and complex phenomenon that highlights the remarkable adaptations found in the animal kingdom.

Research institutes continue to advance their knowledge and understanding of the complex under water environment. Investigation on the movement on plankton and other organisms provide good understanding on how the population can be affected by number of factors such as light and turbulence. A second area of significant study is understanding of how fish, invertebrates and other organisms manage to move through this viscous environment.

The FireFLY laser has been used extensively in this application area and its flexibility in operation is one of the key reasons it is chosen by many. The instrument allows scientists to capture the highest quality of images required to understand the propulsion and hydrodynamic effect. The compact FireFLY unit means scientists can take the imaging system on research field trips to capture images. During the experimental process it is important the fish behave naturally, therefore using the 808nm wavelength FireFLY laser, this is achieved as the light is invisible to the test subject.

FireFLY laser for high speed imaging and PIV