Automated escape system: identifying prey’s kinematic and behavioral features critical for predator evasion

Abstract

AbstractIdentifying the kinematic and behavioral variables of prey that influence the evasion from predator attacks is essential not only for comprehending the determinants of successful predator evasion but also for shedding light on the evolution of specific traits and the dynamics of predator-prey relationships on a larger scale. However, quantifying the relationship between these variables and the success or failure of predator evasion is challenging, particularly for variables with small variations within prey species. One promising approach to address this challenge is the use of a simulated prey system, which allows us to manipulate the kinematic and behavioral features of prey and expose them to real predators. Nevertheless, creating a system that moves comparably to real prey animals remains difficult, especially for invertebrate and lower vertebrate species that respond quickly to predators and escape rapidly.In this study, we have developed an automated escape system that is comparable to real prey species, responding to a predator within tens of milliseconds and escaping at over 1.0 m/s. The system automatically detects an approaching predator and pulls the prey away from the predator once the predator reaches a predetermined threshold distance. Reaction distance, response latency, as well as escaping speed, duration, and direction can be adjusted in the system.By repeatedly measuring the response latency and escaping speed of the system, we demonstrated the system’s ability to exhibit fast and rapid responses while maintaining consistency across successive trials. As a case study, we manipulated the escape speed and reaction distance of the prey to expose them to a predatory fish,Coreoperca kawamebari. The results show that both variables significantly affect the outcome of predator-prey interactions.These findings indicate that the developed escape system is useful for identifying kinematic and behavioral features of prey that are critical for predator evasion. Moreover, due to its relatively low cost and customizability, we propose that this system can be applied to investigate various aspects of animal behaviors (e.g., eliciting escape responses by artificial stimuli) in different animal species.