Predicting success: The effect of prey distance on prey capture success and kinematics in a praying mantis

Although predators exhibit amazing abilities to capture evasive prey, they are not always 100 percent successful in their attempts. For visually motivated predators, such as praying mantids, the distance of the prey may be a key aspect dictating their capture success as prey further away may require greater extension of forelegs, body, or greater speeds to reach the prey before it has a chance to escape. The goal of this research was to examine the role of prey distance on capture success and compare the kinematics of the strikes across these distances. Eleven adult female African praying mantises (Sphodromantis lineola) were filmed capturing mealworm prey attached to small metal wire at 1000 Hz with two-high speed cameras dorsally and laterally. The videos for each view had 10 points along the body and forelegs tracked to obtain a set of 3D kinematics, including angles of each joint, angular velocity, and body movement. Prey distance was taken as the distance between the eye of the mantis and the prey in this 3D space. A total of 193 prey capture events were recorded with 82 successful and 111 failed attempts. Using a binomial regression, prey distance had a significant effect on capture success, with mantises being more successful at closer distances. A PCA of prey capture kinematics regressed again prey distance showed that strikes farther away were faster and bigger. We discuss our results in relation to studies of virtual prey on the strike probability of mantids and trade-offs in speed and accuracy.