Meeting Abstract

P1.94  Friday, Jan. 4  See You on the Flip Side: Tarantula Post-Molt Flipping VEGA, CM*; DOUGHERTY, A; ADEYEMI, T; HRISTOV, N; ASHLEY-ROSS, MA; Wake Forest University; Wake Forest University; Winston-Salem State University; Center for Design Innovation; Wake Forest University vegacm11@wfu.edu

Chilean rose hair tarantulas (Grammostola rosea) shed their hard exoskeletons to accommodate growth. Prior to molting, the tarantula will flip over and lay on its back to “shrug” out of the old exoskeleton. A tarantula’s willingness to remain on its back for extended periods of time is unique to when they are molting as this position makes the tarantula more vulnerable to predator attacks. When not molting, tarantulas that are placed on their backs will quickly flip over onto their feet. We used high-speed video, kinematic analysis, and computer modeling to characterize the essential features of the flipping behavior. External markers were painted on the legs and abdomen for digitizing; these markers were tracked in MatLab for the duration of the flip. Marker positions, combined with scans of a G. rosea exoskeleton, were used to create a 3D computer model of the spider in Maya in order to measure kinematic variables and determine the role of each limb during the flip. The fourth (most posterior) pair of legs is used to lever the cephalothorax off of the substrate, assisted by the third pair of legs. The second pair of legs is typically used to gain purchase with the substrate via the scopular hairs, a motion that involves long-axis twisting of the leg. Once attachment to the substrate is made by one foot, the tarantula appears to pull itself over, using the end of the abdomen as a pivot, finally landing on its feet right-side-up.