# Kinematics and directionality of body turning in water striders (Gerris argentatus) on the water surface

## TL;DR

This study explores how water striders perform precise turns on water surfaces, revealing the coordination of their leg movements and new escape tactics.

## Contribution

The paper introduces the novel concept of reverse sculling as an escape tactic in water striders.

## Key findings

- Midlegs play a pivotal role in maintaining directional movement during turns.
- Water striders adapt their sculling field to perform narrow or wide turns effectively.
- Reverse sculling is a newly identified escape behavior used by water striders.

## Abstract

Water striders inhabit the elastic surface tension film of water, sharing their environment with other aquatic organisms. Their survival relies heavily on swift maneuverability and navigation around floating obstacles, which aids in the exploration of their habitat and in escaping from potential threats. Their high agility is strongly based on the ability to execute precise turns, enabling effective directional control. This paper investigates the intricate coordination of leg movements essential for initiating and sustaining turning maneuvers in water striders. We elucidate the distinct roles of each leg in modulating posture and stability during turns, with a focus on the pivotal role of the midlegs in maintaining directional movement. Through analysis of leg accelerations, decelerations, and load distribution, we unveil the spatiotemporal dynamics governing successful turns. Our findings reveal refined turning strategies employed by water striders in varying situations, from narrow to wide turns, characterized by adaptations in their locomotor system, particularly in the widening of the sculling field. Additionally, we report the phenomenon of reverse sculling, a novel escape tactic of water striders. By shedding light on the maneuverability of water striders, this study contributes to a deeper understanding of animal locomotion strategies in aquatic environments.

This graphical abstract illustrates the kinematics and directionality of body turning in water striders (Gerris argentatus). The top image shows a water strider making turns, with arrows indicating possible directions and a dashed line tracing its path, highlighting its dynamic turning capabilities. The bottom image offers a top‐down view, showing points of contact and load distribution via leg shadows, emphasizing the water strider's position and movement.