Fig. 9.

Pursuit index (γ) for bat–mantis interactions. Gamma is a measure of how close the bat was to a time-optimal pursuit trajectory. γ=–1 indicates a perfectly optimal trajectory, whereas γ=+1 indicates a fully non-optimal trajectory, where the insect was pulling away from the bat (see text for a detailed explanation of γ). (A) γ for captures. The bat maneuvered so that γ → –1 until capture. Limitations of the video data digitization introduce an artifact in the γ computation when the bat gets very close to the target (i.e. just before capture). This artifact has been removed from A, resulting in a gap in the trace just before capture. (B) During aborts γ deviated rapidly from –1 as a result of the dive. (C) During some follows (black line, N=3) the bat kept γ near optimal, before pulling out of the chase. During other follows (gray line, N=3) the bat did not succeed in keeping an optimal γ. (D) During `others' γ was not brought near optimal and the dive did not change the γ trace. Capture/dive time t=0. Mean and standard deviations shown as solid lines and shaded regions, respectively.