Strike kinematics in the whip spider Charon sp. (Amblypygi: Charontidae)

The speed, precision and impact of strikes often determines predatory success. Whip spiders (Arachnida: Amblypygi) are nocturnal ambushing predators that use massive raptorial pedipalps in rapid strikes. While prey capture behavior has been described for a number of amblypygids, the movements performed during the strike have never been resolved in detail, in spite of their strong relevance for the feeding ecology and evolutionary history of this group. Here we studied the attack behavior of Charon sp. on crickets and describe the kinematics of body and pedipalpal movements during the strike. We found that the total strike is performed within 30-180 milliseconds with the pedipalpal tip being accelerated up to 70 m/s² during closure. We found that Charon sp. is able to strike the prey at a lateral angle of up to 30°, which is achieved by non-parallel abduction of the laterigrade legs. These results contribute to our understanding of the evolution of high performance of predatory structures.