Meeting Abstract
P3.89 Jan. 6 Ring following – a novel paradigm for investigating visual edge detection in unrestrained flies DOUGLASS, JK*; DAUM, BT; MAINE, EA; ROBIN, NC; STRAUSFELD, NJ; Univ. of Arizona jkd@neurobio.arizona.edu
Detection of edges and edge orientations is a fundamental feature of visual processing. In insects, functions of edge detection include navigation, foraging and courtship. Foraging flies and honey bees are attracted to edges, particularly those associated with resource patches. Here we describe a remarkably precise form of edge orientation that is reliably elicited in hungry blow flies, Phaenicia sericata. Walking flies are videotaped in a circular arena with a transparent floor and ceiling. The arena�s low walls virtually eliminate flying. Edge stimuli presented below the floor consist of patterns printed on paper and illuminated from below, or patterns displayed directly from a CRT monitor. Responses to paper and CRT stimuli are similar. Flies are more responsive to stripes (paired mirror-symmetrical edges) than to single edges. Upon approaching a stripe that is from ca. 7 to 70° wide, flies of either sex frequently will turn to follow it. When the stripe forms a ring, a fly may circle the ring for several revolutions at a time, continually adjusting its body axis such that deviations from the local orientation of the ring edges are minimized. Visual input is necessary to maintain ring following: upon removal of the ring the fly alters its course immediately. The precision of ring following is at least as high as in visual fixation of vertical stripes by tethered flies. In conclusion, ring following is useful for investigating behavioral orientation to ventral edges in unrestrained flies. Tests with wild-type Drosophila demonstrate similar responses, suggesting that visual behavior mutants and transgene constructs can be used in conjunction with ring-following to elucidate the neural bases of edge detection. Supported by NIH R01 RR008688-17.
