Meeting Abstract
139-1 Tuesday, Jan. 7 13:30 - 13:45 The influence of uneven terrain and vision on ant walking CLIFTON, GT*; HOLWAY, D; GRAVISH, N; Univ. of California, San Diego; UCSD; UCSD glclifton@eng.ucsd.edu
Visual feedback substantially informs vertebrate walking coordination and control, but the ability of some ant species to forage at night and through dark tunnels suggests that vision may be less essential for certain insects. To understand how vision influences walking performance under naturally rugged conditions, we recorded 3900 high-speed videos of Argentine ants (Linepithema humile) walking on 3D-printed substrates both in light and dark conditions. Ants walking on flat ground showed a small, but significant shift to slower speeds in the dark. On a checkerboard substrate, ants walked 50% slower but, surprisingly, lighting did not influence speed. Pathway sinuosity increased on the checkerboard array but did not change between light and dark conditions. Since many walking perturbation studies focus on a discrete step, we also included a step substrate. When confronted with a step up, ants decelerated on average ~2.8 mm before the step, a distance corresponding to when the antennae first contact the step. For stepping down, ants slowed down <1 mm from the step approximately when the forelimbs would reach the step edge, regaining original speeds only 2.5-3 mm after the step. Together these findings support that vision does not critically impact walking for the Argentine ant, especially on uneven terrain. Instead, ants could either walk without sensory feedback or by relying on tactile and proprioceptive cues from the antennae and limbs. The reduced influence of vision in this ant species could stem from slow visual perception relative to movement speeds and from the ability to generate large body accelerations using specialized tarsal structures. These results have the potential to inform insect neuromechanics, inspire new robotic control strategies, and explain ecological patterns in life history.