Dynamics of animal movement in an ecological context: dragonfly wing damage reduces flight performance and predation success

Abstract

Much of our understanding of the control and dynamics of animal movement derives from controlled laboratory experiments. While many aspects of animal movement can be probed only in these settings, a more complete understanding of animal locomotion may be gained by linking experiments on relatively simple motions in the laboratory to studies of more complex behaviours in natural settings. To demonstrate the utility of this approach, we examined the effects of wing damage on dragonfly flight performance in both a laboratory drop-escape response and the more natural context of aerial predation. The laboratory experiment shows that hindwing area loss reduces vertical acceleration and average flight velocity, and the predation experiment demonstrates that this type of wing damage results in a significant decline in capture success. Taken together, these results suggest that wing damage may take a serious toll on wild dragonflies, potentially reducing both reproductive success and survival.

Figure 1.

Effects of hindwing area removal on dragonfly flight performance during laboratory drop–escape tests. (a) Sample data from dragonfly no. 4 showing vertical position (dark grey), velocity (light grey) and acceleration (black) versus time with intact wings, 30% hindwing area removal and 50% hindwing area removal. Peak acceleration is marked with a diamond, and the end of the drop–start of the escape response is shown with a dashed line. (b) Peak vertical accelerations produced by dragonflies to arrest their fall. (c) Time-averaged velocity during the first 0.15 s of the escape. Shaded triangle, intact; shaded circle, 30% hindwing loss; and shaded square, 50% hindwing loss. Symbols indicate mean ± s.e. In the control dragonfly, the three symbols represent trials 1–5, 6–10 and 11–15, respectively.

Figure 2.

Effect of hindwing area removal on predation success rate. (a) Sample trajectories of predation flights demonstrating the variability and complexity of this behaviour. The star represents the dragonfly's perch, and arrows indicate the direction of flight. (b) Effect of 30% hindwing area removal on predation success rate in five individuals.