Prey capture by the whip spider \u3ci\u3ePhrynus marginemaculatus\u3c/i\u3e C.L. Koch

Whip spiders (Arachnida, Amblypygi) are little-studied arachnids with enlarged spiny pedipalps and elongated ‘‘antenniform’’ forelegs. These antenniform legs contain at least seven giant sensory neurons with no known behavioral function. Here we use high-speed cinematography to describe the prey capture behavior of the whip spider Phrynus marginemaculatus C.L. Koch 1840, in order to examine how these giant neurons might be involved. When presented with a prey item (a cricket), a whip spider first accurately aims one of its antenniform legs in the prey’s direction. Next, the whip spider orients its body to the prey item and approaches, placing one antenniform leg tip on either side of the prey. The whip spider may remain relatively still in this position for some time, before opening its pedipalps in preparation for a strike and then rapidly swinging its antenniform legs away from the prey item and striking at it with its pedipalps. In common with previous studies, our results show that giant neuron activity is not necessary to trigger any of the stages of normal prey capture behavior, but they also suggest that these neurons could still provide information important in this context