ASHLEY-ROSS, MA*; WADE, HS; Wake Forest University; Wake Forest University: Fearsome fangs and fast feet: Kinematics of prey capture in tarantulas

Tarantulas are large, predatory spiders of the family Theraphosidae. Adult sizes range from 4 � 10 inches across the outspread legs, and these spiders are capable of eating prey up to mice and birds in size, though much of their diet consists of insects. Unlike many derived spider families, tarantulas do not spin webs for prey capture; instead, the theraphosids strike and subdue prey using their appendages. We used high-speed video at 500 frames per second to record and analyze a minimum of five successful strikes on crickets of three species of tarantula: the Mexican Red-Knee (Brachypelma smithi), Chilean Rose-Hair (Grammostola rosea) and Guyana Pinktoe (Avicularia avicularia). Contrary to our initial expectations, the fangs are not used in the initial strike to contact the prey. Rather, the first two pairs of legs are typically reached over the cricket, and used to scoop the prey in toward the mouth. As soon as the prey comes within reach of the pedipalps, these shorter appendages are used to position the cricket under the fangs. The fangs then pierce the prey while the pedipalps and first two pairs of legs hold the prey stationary. Time taken from first movement of the legs to piercing the prey with the fangs is approximately 300 ms. Following initial mastication of the cricket with the chelicerae, the tarantulas often spin a diffuse mat of silk on the ground, drop the mashed-up prey onto the silk, spin more silk to cover the prey, and finally pick up the �wrapped package� for further mastication and ingestion. Though the basic sequence of events in prey capture and processing is stereotyped, tarantulas are capable of extensive modulation in the direction of the strike, and the amount and kind of post-capture processing.