Optimal Random Avoidance Strategy in Prey-Predator Interactions

Abstract

16It has recently been reported that individual animals, ranging from insects to birds and mammals, 17 exhibit a special class of random walks, known as Lévy walks, which can lead to higher search 18 efficiency than normal random walks. However, the role of randomness or unpredictability in 19 animal movements is not very well understood. In the present study, we used a theoretical 20 framework to explore the advantage of Lévy walks in terms of avoidance behaviour in prey-21 predator interactions and analysed the conditions for maximising the prey's survival rate. We 22 showed that there is a trade-off relationship between the predictability of the prey's movement 23 and the length of time of exposure to predation risk, suggesting that it is difficult for prey to 24 decrease both parameters in order to survive. Then, we demonstrated that the optimal degree of 25 randomness in avoidance behaviour could change depending on the predator's ability. In 26 particular, Lévy walks resulted in higher survival rates than normal random walks and straight 27 movements when the physical ability of the predators was high. This indicates that the advantage 28 of Lévy walks may also be present in random avoidance behaviour and provides new insights into 29 why Lévy walks can evolve in terms of randomness. 30 31 Keywords: Lévy walks, avoidance behaviour, prey-predator interactions, movement ecology 32 33 34 35 36

Quantitative Assessment and Analysis of Fish Behavior in Closed Systems Using Information Entropy

“…For instance, ballistic movements, which involve moving in a persistent direction (e.g., away from a predator), have been suggested as a better strategy to avoid predators in certain situations [27]. Reports by Steckbauer et al (2018) and Abe M. and Kasada M. (2020) support the idea that random movements can be an effective avoidance strategy [28,29]. Thus, while our results indicate that random movements are advantageous, it is essential to consider these findings within the broader spectrum of predator-prey interaction strategies.…”