Meeting Abstract
Multisensory integration is crucial for many animal behaviors. In flies, information from the mechanosensory halteres is combined with information from the visual system. Without this mechanosensory information, flies are unable to fly freely. We ablated the halteres of fruit flies (Drosophila melanogaster) and found that they are able to fly normally if glued to a rigid pin. This tethering prevents them from rotating their bodies, but permits them to steer their wings as they would in free flight. In doing so, we are able to observe the behavioral effects of the relationship between halteres and the visual system independently of the haltere’s sensing of body rotations. We manipulated the haltere by removing the end-bulb to decrease the mass, and by removing the entire haltere including the campaniform sensilla. We find that manipulating the mass of the haltere has no effect on the fly’s wing-steering efforts, but removing the campaniform sensilla prevents flies from responding to wide-field open-loop visual stimulation. Despite their defects in responding to wide-field stimuli, haltereless flies presented with a moving figure or a moving figure on a moving background showed similar responses to intact flies. Similarly, when flies are allowed to use their wing steering to control their own visual stimulus in closed-loop simulations, haltereless flies are able to fixate a figure in the frontal field, but cannot stabilize a wide-field stimulus. Our manipulations of the haltere feedback loop show that the haltere campaniform sensilla are necessary for wing-steering responses to wide-field visual stimulus, but the added mass of the haltere bulb is not.
