Meeting Abstract
Animal behavior requires the integration of multiple sensory information streams. For flying animals, stability and control require the rapid integration of visual and mechanosensory information. Information about body rotations in flying flies is provided with high speed and precision by the halteres, reduced hindwings that are essential for fly flight. Previous studies have shown that halteres are not are not strictly necessary for visually-guided wing steering responses in fruit flies, but their influence on wing-steering behavior can change depending on visual context. In this study, we asked whether the halteres might influence head movements in the same way they influence wing steering. We examined the head movement behavior of intact fruit flies, flies with the haltere mass ablated (leaving the sensory cells intact but reducing the force on them), and flies with complete haltere ablations. Each group of flies flew on a rigid tether in multiple visual contexts. Although haltere input is necessary for spiking activity in some neck motoneurons of larger flies, we found that haltere removal did not decrease the flies’ range of head movements. When the flies were stimulated with visual motion, we found that haltere ablation decreased head movement responses to wide-field motion, but not to moving figures. In closed loop, fast head movements (saccades) occurred more frequently during periods in which the fly was fixating a figure in the frontal field, but did not occur more frequently during wide-field fixation. Our results suggest a complex role for the haltere in gaze control that is modulated by visual context. Although the wing-steering and head movement behaviors are different in the visual contexts tested here, the influence of the haltere appears to be similar for both.
