Biology subjects

Ros, I. G.

Publications and source records attributed to Ros, I. G..

4 recordsLinked to original sources

bioRxiv2026

Flies evolved a gyrocompass to maintain navigational accuracy during rapid flight maneuvers

Halteres, the miniaturized hindwings of flies, function as biological gyroscopes that encode angular velocity during flight. Although their established role is to detect flight perturbations and trigger compensatory manoeuvers, here we show that halteres also function as a gyrocompass, maintaining an accurate estimate of heading during rapid turns. To overcome the incompatibility between rapid body rotations and two-photon imaging, we exploited the physics of haltere mechano-transduction to reproduce the inertial forces acting on the halteres during rapid body rotations using micron-scale oscillations of the thorax. Our experiments demonstrate that flies update their internal compass during rapid turns by integrating inertial measurements with predictions derived from efference copy signals. Because body saccades exceed the temporal bandwidth of visual motion processing, this inertial computation allows flies to maintain an accurate internal compass throughout these rapid manoeuvres. This capability may enable flies to compute critical parameters such as wind direction and ground speed by comparing measurements made before and after each saccade. Our findings suggest that an ancestral flight-stabilization system was evolutionarily co-opted into a biological gyrocompass, a new function that may have contributed to the adaptive radiation of flies.

neuroscience↗

bioRxiv2026

A view of bird's eyes -- Pigeons lock their eyes in place during flight

Vision in most animals follows a fixate-and-saccade pattern. Birds fixate their viewing direction, then rapidly shift this gaze through head and eye movements. We used a head-mounted eye-tracking system in flying pigeons to relate eye to head movement and map eye position within the head. After take-off, the birds increased pupil size and adopted a fixed and consistent eye position in their head. In different visual environments, eye position returned to within 1{degrees} during flight. When flying, the birds positioned their eyes close to the primary horizontal axes of their vestibular systems. Because visual neurons share a common reference frame with the vestibular system, a consistent flight gaze position may actively align vision with mechanosensation and facilitate perception of self-motion. One-Sentence SummaryA head-mounted eye-tracking system shows that pigeons adopt a consistent eye-in-head position during free flight

animal behavior and cognition↗

bioRxiv2023

Descending control and regulation of spontaneous flight turns in Drosophila

The clumped distribution of resources in the world has influenced the pattern of foraging behavior since the origins of life, selecting for a common locomotor search motif in which straight movements through resource-poor regions alternate with zig-zag exploration in resource-rich domains (Berg, 2000). For example, flies execute rapid changes in flight heading called body saccades during local search (Censi et al., 2013; Collett and Land, 1975; Schilstra and van Hateren, 1999; Wagner and Land, 1986), but suppress these turns during long-distance dispersal (Giraldo et al., 2018; Leitch et al., 2021) or when surging upwind after encountering an attractive odor plume (Budick and Dickinson, 2006; van Breugel and Dickinson, 2014). Here, we describe the key cellular components of a neural network in flies that generates spontaneous turns as well as a specialized neuron that inhibits the network to promote straight flight. Using 2-photon imaging, optogenetic activation, and genetic ablation, we show that only four descending neurons appear sufficient to generate the descending commands to execute flight saccades. The network is organized into two functional couplets--one for right turns and one for left--with each couplet consisting of an excitatory (DNae014) and inhibitory (DNb01) neuron that project to the flight motor neuropil within the ventral nerve cord. Using resources from recently published connectomes of the fly brain (Scheffer et al., 2020; Dorkenwald et al., 2023; Schlegel et al., 2023), we identified a large, unique interneuron (VES041) that forms inhibitory connections to all four saccade command neurons and created specific genetic driver lines for this cell. As predicted by its connectivity, activation of VES041 strongly suppresses saccades, suggesting that it regulates the transition between local search and long-distance dispersal. These results thus identify the critical elements of a network that not only structures the locomotor behavior of flies, but may also play a crucial role in their foraging ecology.

neuroscience↗

bioRxiv2021

A population of descending neurons that regulate the flight motor of Drosophila

Like many insect species, Drosophila melanogaster are capable of maintaining a stable flight trajectory for periods lasting up to several hours(1, 2). Because aerodynamic torque is roughly proportional to the fifth power of wing length(3), even small asymmetries in wing size require the maintenance of subtle bilateral differences in flapping motion to maintain a stable path. Flies can even fly straight after losing half of a wing, a feat they accomplish via very large, sustained kinematic changes to the both damaged and intact wings(4). Thus, the neural network responsible for stable flight must be capable of sustaining fine-scaled control over wing motion across a large dynamic range. In this paper, we describe an unusual type of descending neurons (DNg02) that project directly from visual output regions of the brain to the dorsal flight neuropil of the ventral nerve cord. Unlike most descending neurons, which exist as single bilateral pairs with unique morphology, there is a population of at least 15 DNg02 cell pairs with nearly identical shape. By optogenetically activating different numbers of DNg02 cells, we demonstrate that these neurons regulate wingbeat amplitude over a wide dynamic range via a population code. Using 2-photon functional imaging, we show that DNg02 cells are responsive to visual motion during flight in a manner that would make them well suited to continuously regulate bilateral changes in wing kinematics. Collectively, we have identified a critical set of DNs that provide the sensitivity and dynamic range required for flight control.

neuroscience↗