Characterization of Head and Antenna Dynamics of Undulatory Wall-following in Scolopendra subspinipes

Nocturnal arthropods, especially those with poor visual acuity, use mechanical cues from their legs and antenna to navigate in their cluttered environments. Studies in cockroaches show that when they wall-follow, their head-to-wall distance is constant when following along a flat wall, inversely related to their average velocity, and controlled by their antenna-wall interaction (Cowan et al., 2006). Unlike cockroaches, centipedes like Scolopendra subspinipes have elongate bodies that use both waves of body undulation and limb-stepping that causes the head to oscillate when it walks. This oscillation provides a number of questions about how centipedes wall-follow, despite their locomotion pattern potentially preventing a constant following distance. We recorded 5 S. subspinipes performing wall following along a flat wall (L=40cm). We observed that centipedes followed along flat walls with speed of 5 to 32 cm/s and had average following distances of 0.4 to 5.2 cm. Larger following distances were associated with higher speeds. Additionally, we observed higher wall-antenna interactions with higher speeds. We hypothesize that this difference in the distance-speed relationship is a result of the differences in body mechanics and behavior modulation, via antennal stimulation, of centipedes and cockroaches.