Simulating rolling paths and reorientation behavior of ball-rolling dung beetles

Ball-rolling dung beetles show a remarkable ability to maintain a straight path while rolling dung balls away from a dung pile. Rolling in a straight line is beneficial, as it enables beetles to efficiently escape competition near the dung pile. Research has shown that beetles use the sky to choose and maintain an initial rolling direction, and to reorient (correct their direction) when pushed off their intended course by obstacles or uneven ground. While beetles' mechanisms for navigation are well understood, it remains unclear how beetles regulate the timing of reorientation and under what circumstances reorientation is beneficial. Previous studies have focused only on the observable data from the movement of real dung beetles, in the field and simulated environments. In this paper, we formulate a mathematical model based on a persistent random walk to simulate a dung beetle's movement in a circular arena. We simulate two possible reorientation strategies and analyze the impact when reorientation is not perfect. We show that our model provides an approximation of actual dung ball rolling paths, analyze the benefits of each reorientation technique under varying conditions, and show that when the sky is obscured, rolling without reorientation can be a beetle's optimal strategy. (C) 2019 Elsevier Ltd. All rights reserved.