Meeting Abstract

17.3  Friday, Jan. 4  Flying fruit flies correct for visual sideslip using motion parallax cues THEOBALD, J. C.*; CABRERA, S; Florida International University theobald@fiu.edu

Fruit flies possess tiny brains, but still depend on sophisticated flight skills to navigate to food, mates, and oviposition sites. A tenet of stable flight is the ability to correct for deviations from an intended course, such as by a gust of wind. One means by which flies do this is optic flow stabilization; when the visual world abruptly seems to move to the left, flies steer to the left to compensate. In previous experiments with static flies immersed in moving flow fields of points, forward motion had no effect on these side corrective responses. In other words, flies that appeared to be moving forward slowly, quickly, or even backwards responded identically to sideways visual perturbations. However optic flow during forward flight is a mix of images that seem to move faster or slower depending on their distance. When just the faster, seemingly nearer points move sideways, flies respond more robustly than when just the slower, seemingly farther points move, and this holds regardless of absolute forward speed. This result is consistent with the theory that flying flies, which cannot use binocular or accommodation cues for depth, use motion parallax to attend to nearer, more relevant features