D3147: Effects of prey size on prey capture kinematics in the orchid mantis (Hymenopus coronatus)

Flexibility in a behavior is when an organism senses a change in stimuli and responds accordingly. Flexibility during prey capture may provide predators with a wider range of potential prey. Our project aimed to determine whether prey capture in Orchid mantises (Hymenopus coronatus), a flower mimic who rely on crypsis to capture unsuspecting prey, is flexible in relation to varying prey sizes. To test this, we filmed the feeding strikes of 11 adult female H. coronatus capturing three size ranges of roach – small (< .150 g), medium (.150-.250g), and large ( >.250g). Each female was tested a minimum of 15 times randomly on five roaches of each prey size, resulting in more than 150 prey capture events. Prey capture events were filmed using two highspeed cameras from a lateral and ventral view at 1000 Hz. Ten points were tracked on each view using machine learning and manual tracking to obtain 3D kinematics, such angles and angular velocities of each foreleg segment. If the mantis prey capture is flexible in relation to changes in prey size, this would suggest they can perceive prey size and adjust their prey capture strikes accordingly. For example, larger prey may elicit increased angles of the foreleg joints. Flexibility in relation to prey size would further suggest that the strike is not entirely preprogrammed, as has been shown recently in other species of praying mantis capturing prey moving at various speeds.