@article {69401, title = {Machine learning reveals the control mechanics of an insect wing hinge}, journal = {Nature}, volume = {628}, year = {2024}, month = {2024 Apr 17}, pages = {795-803}, abstract = {

Insects constitute the most species-rich radiation of metazoa, a success that is due to the evolution of active flight. Unlike pterosaurs, birds and bats, the wings of insects did not evolve from legs, but are novel structures that are attached to the body via a biomechanically complex hinge that transforms tiny, high-frequency oscillations of specialized power muscles into the sweeping back-and-forth motion of the wings. The hinge consists of a system of tiny, hardened structures called sclerites that are interconnected to one another via flexible joints and regulated by the activity of specialized control muscles. Here we imaged the activity of these muscles in a fly using a genetically encoded calcium indicator, while simultaneously tracking the three-dimensional motion of the wings with high-speed cameras. Using machine learning, we created a convolutional neural network that accurately predicts wing motion from the activity of the steering muscles, and an encoder-decoder that predicts the role of the individual sclerites on wing motion. By replaying patterns of wing motion on a dynamically scaled robotic fly, we quantified the effects of steering muscle activity on aerodynamic forces. A physics-based simulation incorporating our hinge model generates flight manoeuvres that are remarkably similar to those of free-flying flies. This integrative, multi-disciplinary approach reveals the mechanical control logic of the insect wing hinge, arguably among the most sophisticated and evolutionarily important skeletal structures in the natural world.

}, keywords = {Animals, Biomechanical Phenomena, Calcium, Drosophila melanogaster, Female, Flight, Animal, Machine Learning, Movement, Muscles, Neural Networks, Computer, Robotics, Wings, Animal}, issn = {1476-4687}, doi = {10.1038/s41586-024-07293-4}, author = {Melis, Johan M and Siwanowicz, Igor and Dickinson, Michael H} } @article {68557, title = {Neuromuscular embodiment of feedback control elements in flight.}, journal = {Science Advances}, volume = {8}, year = {2022}, month = {2022 Dec 14}, pages = {eabo7461}, abstract = {

While insects such as are flying, aerodynamic instabilities require that they make millisecond time scale adjustments to their wing motion to stay aloft and on course. These stabilization reflexes can be modeled as a proportional-integral (PI) controller; however, it is unclear how such control might be instantiated in insects at the level of muscles and neurons. Here, we show that the b1 and b2 motor units-prominent components of the fly{\textquoteright}s steering muscle system-modulate specific elements of the PI controller: the angular displacement (integral) and angular velocity (proportional), respectively. Moreover, these effects are observed only during the stabilization of pitch. Our results provide evidence for an organizational principle in which each muscle contributes to a specific functional role in flight control, a finding that highlights the power of using top-down behavioral modeling to guide bottom-up cellular manipulation studies.

}, issn = {2375-2548}, doi = {10.1126/sciadv.abo7461}, author = {Whitehead, Samuel C and Leone, Sofia and Lindsay, Theodore and Meiselman, Matthew R and Cowan, Noah J and Dickinson, Michael H and Yapici, Nilay and Stern, David L and Shirangi, Troy and Cohen, Itai} } @article {67892, title = {A population of descending neurons that regulates the flight motor of Drosophila.}, journal = {Current Biology}, volume = {32}, year = {2022}, month = {2022 Mar 14}, pages = {1189-1196}, abstract = {

Similar to many insect species, Drosophila melanogaster is capable of maintaining a stable flight trajectory for periods lasting up to several hours. Because aerodynamic torque is roughly proportional to the fifth power of wing length, 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 both the damaged and intact wings. 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 study, we describe an unusual type of descending neuron (DNg02) that projects directly from visual output regions of the brain to the dorsal flight neuropil of the ventral nerve cord. Unlike many 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 two-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 descending neurons that provides the sensitivity and dynamic range required for flight control.

}, issn = {1879-0445}, doi = {10.1016/j.cub.2022.01.008}, author = {Namiki, Shigehiro and Ros, Ivo G and Morrow, Carmen and Rowell, William J and Card, Gwyneth M and Korff, Wyatt and Dickinson, Michael H} } @article {67672, title = {jumps with greater velocity and acceleration than previously reported.}, journal = {MicroPublication Biology}, volume = {2021}, year = {2021}, month = {2021 Aug 02}, abstract = {

Infective juveniles of the insect-parastic nematode canjump greater than 6 times their height, a striking evolved novelty in some species of this genus. Using high-speed videography, we observed the kinematics of spontaneousjumping behavior. Our analysis places a lower bound on the velocity and acceleration of these worms.

}, issn = {2578-9430}, doi = {10.17912/micropub.biology.000435}, author = {Dillman, Adler R and Korff, Wyatt and Dickinson, Michael H and Sternberg, Paul W} } @article {48975, title = {The functional organization of descending sensory-motor pathways in Drosophila.}, journal = {eLife}, year = {2017}, month = {2018 Jun 26}, pages = {e34272}, abstract = {

In most animals, the brain controls the body via a set of descending neurons (DNs) that traverse the neck. DN activity activates, maintains or modulates locomotion and other behaviors. Individual DNs have been well-studied in species from insects to primates, but little is known about overall connectivity patterns across the DN population. We systematically investigated DN anatomy in\ Drosophila melanogaster\ and created over 100 transgenic lines targeting individual cell types. We identified roughly half of all\ Drosophila\ DNs and comprehensively map connectivity between sensory and motor neuropils in the brain and nerve cord, respectively. We find the nerve cord is a layered system of neuropils reflecting the fly{\textquoteright}s capability for two largely independent means of locomotion -- walking and flight -- using distinct sets of appendages. Our results reveal the basic functional map of descending pathways in flies and provide tools for systematic interrogation of neural circuits.

}, doi = {10.7554/eLife.34272}, author = {Namiki, Shigehiro and Dickinson, Michael H and Wong, Allan M and Korff, Wyatt and Card, Gwyneth M} } @article {48657, title = {A systematic nomenclature for the Drosophila ventral nervous system.}, journal = {bioRxiv}, year = {2017}, month = {2017 Apr 26}, abstract = {

Insect nervous systems are proven and powerful model systems for neuroscience research with wide relevance in biology and medicine. However, descriptions of insect brains have suffered from a lack of a complete and uniform nomenclature. Recognising this problem the Insect Brain Name Working Group produced the first agreed hierarchical nomenclature system for the adult insect brain, using Drosophila melanogaster as the reference framework, with other insect taxa considered to ensure greater consistency and expandability (Ito et al., 2014). Ito et al. (2014) purposely focused on the gnathal regions that account for approximately 50\% of the adult CNS. We extend this nomenclature system to the sub-gnathal regions of the adult Drosophila nervous system to provide a nomenclature of the so-called ventral nervous system (VNS), which includes the thoracic and abdominal neuromeres that was not included in the original work and contains the neurons that play critical roles underpinning most fly behaviours.

}, doi = {10.1101/122952}, author = {Court, Robert Christopher and Armstrong, James Douglas and Borner, Jana and Card, Gwyneth M and Costa, Marta and Dickinson, Michael H and Duch, Carsten and Korff, Wyatt and Mann, Richard S and Merritt, David and Murphey, Rodney K and Namiki, Shigehiro and Seeds, Andrew M and Shepherd, David and Shirangi, Troy R and Simpson, Julie H and Truman, James W and Tuthill, John C and Williams, Darren W} } @article {6953, title = {Flying Drosophila stabilize their vision-based velocity controller by sensing wind with their antennae.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {111}, year = {2014}, month = {2014 Apr 1}, pages = {E1182-91}, abstract = {

Flies and other insects use vision to regulate their groundspeed in flight, enabling them to fly in varying wind conditions. Compared with mechanosensory modalities, however, vision requires a long processing delay (\ 100 ms) that might introduce instability if operated at high gain. Flies also sense air motion with their antennae, but how this is used in flight control is unknown. We manipulated the antennal function of fruit flies by ablating their aristae, forcing them to rely on vision alone to regulate groundspeed. Arista-ablated flies in flight exhibited significantly greater groundspeed variability than intact flies. We then subjected them to a series of controlled impulsive wind gusts delivered by an air piston and experimentally manipulated antennae and visual feedback. The results show that an antenna-mediated response alters wing motion to cause flies to accelerate in the same direction as the gust. This response opposes flying into a headwind, but flies regularly fly upwind. To resolve this discrepancy, we obtained a dynamic model of the fly{\textquoteright}s velocity regulator by fitting parameters of candidate models to our experimental data. The model suggests that the groundspeed variability of arista-ablated flies is the result of unstable feedback oscillations caused by the delay and high gain of visual feedback. The antenna response drives active damping with a shorter delay (\ 20 ms) to stabilize this regulator, in exchange for increasing the effect of rapid wind disturbances. This provides insight into flies{\textquoteright} multimodal sensory feedback architecture and constitutes a previously unknown role for the antennae.

}, issn = {1091-6490}, doi = {10.1073/pnas.1323529111}, author = {Fuller, Sawyer Buckminster and Straw, Andrew D and Peek, Martin Y and Murray, Richard M and Dickinson, Michael H} } @article {6102, title = {Visual motion speed determines a behavioral switch from forward flight to expansion avoidance in Drosophila.}, journal = {The Journal of Experimental Biology}, volume = {216}, year = {2013}, month = {2013 Feb 15}, pages = {719-32}, abstract = {

As an animal translates through the world, its eyes will experience a radiating pattern of optic flow in which there is a focus of expansion directly in front and a focus of contraction behind. For flying fruit flies, recent experiments indicate that flies actively steer away from patterns of expansion. Whereas such a reflex makes sense for avoiding obstacles, it presents a paradox of sorts because an insect could not navigate stably through a visual scene unless it tolerated flight towards a focus of expansion during episodes of forward translation. One possible solution to this paradox is that a fly{\textquoteright}s behavior might change such that it steers away from strong expansion, but actively steers towards weak expansion. In this study, we use a tethered flight arena to investigate the influence of stimulus strength on the magnitude and direction of turning responses to visual expansion in flies. These experiments indicate that the expansion-avoidance behavior is speed dependent. At slower speeds of expansion, flies exhibit an attraction to the focus of expansion, whereas the behavior transforms to expansion avoidance at higher speeds. Open-loop experiments indicate that this inversion of the expansion-avoidance response depends on whether or not the head is fixed to the thorax. The inversion of the expansion-avoidance response with stimulus strength has a clear manifestation under closed-loop conditions. Flies will actively orient towards a focus of expansion at low temporal frequency but steer away from it at high temporal frequency. The change in the response with temporal frequency does not require motion stimuli directly in front or behind the fly. Animals in which the stimulus was presented within 120 deg sectors on each side consistently steered towards expansion at low temporal frequency and steered towards contraction at high temporal frequency. A simple model based on an array of Hassenstein-Reichardt type elementary movement detectors suggests that the inversion of the expansion-avoidance reflex can explain the spatial distribution of straight flight segments and collision-avoidance saccades when flies fly freely within an open circular arena.

}, keywords = {Animal, Animals, Avoidance Learning, Behavior, Drosophila melanogaster, Female, Flight, Motion Perception, Orientation, Photic Stimulation, Time Factors, Visual Perception}, issn = {1477-9145}, doi = {10.1242/jeb.074732}, author = {Reiser, Michael B and Dickinson, Michael H} } @article {5036, title = {A simple strategy for detecting moving objects during locomotion revealed by animal-robot interactions.}, journal = {Current Biology}, volume = {22}, year = {2012}, month = {2012 Jun 20}, pages = {1344-50}, abstract = {

An important role of visual systems is to detect nearby predators, prey, and potential mates [1], which may be distinguished in part by their motion. When an animal is at rest, an object moving in any direction may easily be detected by motion-sensitive visual circuits [2, 3]. During locomotion,\ however, this strategy is compromised because the observer must detect a moving object within the pattern of\ optic flow created by its own motion through the stationary\ background. However, objects that move creating back-to-front (regressive) motion may be unambiguously distinguished from stationary objects because forward locomotion creates only front-to-back (progressive) optic flow. Thus, moving animals should exhibit an enhanced sensitivity to regressively moving objects. We explicitly tested this hypothesis by constructing a simple fly-sized robot that was programmed to interact with a real fly. Our measurements indicate that whereas walking female flies freeze in response to a regressively moving object, they ignore a progressively moving one. Regressive motion salience also explains observations of behaviors exhibited by pairs of walking flies. Because the assumptions underlying the regressive motion salience hypothesis are general, we suspect that the behavior we have observed in Drosophila may be widespread among eyed, motile organisms.

}, issn = {1879-0445}, doi = {10.1016/j.cub.2012.05.024}, author = {Zabala, Francisco and Polidoro, Peter and Robie, Alice A and Branson, Kristin and Perona, Pietro and Dickinson, Michael H} } @article {2161, title = {Multi-camera real-time three-dimensional tracking of multiple flying animals.}, journal = {Journal of the Royal Society, Interface}, volume = {8}, year = {2011}, month = {2011 Mar 6}, pages = {395-409}, abstract = {

Automated tracking of animal movement allows analyses that would not otherwise be possible by providing great quantities of data. The additional capability of tracking in real time{\textendash}with minimal latency{\textendash}opens up the experimental possibility of manipulating sensory feedback, thus allowing detailed explorations of the neural basis for control of behaviour. Here, we describe a system capable of tracking the three-dimensional position and body orientation of animals such as flies and birds. The system operates with less than 40 ms latency and can track multiple animals simultaneously. To achieve these results, a multi-target tracking algorithm was developed based on the extended Kalman filter and the nearest neighbour standard filter data association algorithm. In one implementation, an 11-camera system is capable of tracking three flies simultaneously at 60 frames per second using a gigabit network of nine standard Intel Pentium 4 and Core 2 Duo computers. This manuscript presents the rationale and details of the algorithms employed and shows three implementations of the system. An experiment was performed using the tracking system to measure the effect of visual contrast on the flight speed of Drosophila melanogaster. At low contrasts, speed is more variable and faster on average than at high contrasts. Thus, the system is already a useful tool to study the neurobiology and behaviour of freely flying animals. If combined with other techniques, such as {\textquoteright}virtual reality{\textquoteright}-type computer graphics or genetic manipulation, the tracking system would offer a powerful new way to investigate the biology of flying animals.

}, issn = {1742-5662}, doi = {10.1098/rsif.2010.0230}, author = {Straw, Andrew D and Branson, Kristin and Neumann, Titus R and Dickinson, Michael H} } @article {2353, title = {Drosophila fly straight by fixating objects in the face of expanding optic flow.}, journal = {The Journal of Experimental Biology}, volume = {213}, year = {2010}, month = {2010 May}, pages = {1771-81}, abstract = {

Flies, like all animals that depend on vision to navigate through the world, must integrate the optic flow created by self-motion with the images generated by prominent features in their environment. Although much is known about the responses of Drosophila melanogaster to rotating flow fields, their reactions to the more complex patterns of motion that occur as they translate through the world are not well understood. In the present study we explore the interactions between two visual reflexes in Drosophila: object fixation and expansion avoidance. As a fly flies forward, it encounters an expanding visual flow field. However, recent results have demonstrated that Drosophila strongly turn away from patterns of expansion. Given the strength of this reflex, it is difficult to explain how flies make forward progress through a visual landscape. This paradox is partially resolved by the finding reported here that when undergoing flight directed towards a conspicuous object, Drosophila will tolerate a level of expansion that would otherwise induce avoidance. This navigation strategy allows flies to fly straight when orienting towards prominent visual features.

}, keywords = {Animal, Animals, Drosophila melanogaster, Fixation, Flight, Ocular, Photic Stimulation, Visual Pathways}, issn = {1477-9145}, doi = {10.1016/j.cub.2010.06.072}, author = {Reiser, Michael B and Dickinson, Michael H} } @conference {48656, title = {Dynamics of escaping flight initiations of Drosophila melanogaster.}, booktitle = {2nd IEEE RAS \& EMBS International Conference on Biomedical Robotics and Biomechatronics}, year = {2009}, month = {2008}, abstract = {

We present a reconstruction of the dynamics of flight initiation from kinematic data extracted from high-speed video recordings of the fruit fly Drosophila melanogaster. The dichotomy observed in this insect{\textquoteright}s flight initiation sequences, generated by the presence or absence of visual stimuli, clearly generates two contrasting sets of dynamics once the flies become airborne. By calculating reaction forces and moments using the unconstrained motion formulation for a rigid body, we assess the fly{\textquoteright}s responses amidst these two dynamic patterns as a step towards refining our understanding of insect flight control.

}, doi = {10.1109/BIOROB.2008.4762921}, author = {Zabalax, Francisco A and Card, Gwyneth M and Fontaine, Ebraheem I and Murray, Richard M and Dickinson, Michael H} } @article {2168, title = {Flight dynamics and control of evasive maneuvers: the fruit fly{\textquoteright}s takeoff.}, journal = {IEEE Transactions on Bio-Medical Engineering}, volume = {56}, year = {2009}, month = {2009 Sep}, pages = {2295-8}, abstract = {

We have approached the problem of reverse-engineering the flight control mechanism of the fruit fly by studying the dynamics of the responses to a visual stimulus during takeoff. Building upon a prior framework [G. Card and M. Dickinson, J. Exp. Biol., vol. 211, pp. 341-353, 2008], we seek to understand the strategies employed by the animal to stabilize attitude and orientation during these evasive, highly dynamical maneuvers. As a first step, we consider the dynamics from a gray-box perspective: examining lumped forces produced by the insect{\textquoteright}s legs and wings. The reconstruction of the flight initiation dynamics, based on the unconstrained motion formulation for a rigid body, allows us to assess the fly{\textquoteright}s responses to a variety of initial conditions induced by its jump. Such assessment permits refinement by using a visual tracking algorithm to extract the kinematic envelope of the wings [E. I. Fontaine, F. Zabala, M. Dickinson, and J. Burdick, "Wing and body motion during flight initiation in Drosophila revealed by automated visual tracking," submitted for publication] in order to estimate lift and drag forces [F. Zabala, M. Dickinson, and R. Murray, "Control and stability of insect flight during highly dynamical maneuvers," submitted for publication], and recording actual leg-joint kinematics and using them to estimate jump forces [F. Zabala, "A bio-inspired model for directionality control of flight initiation," to be published.]. In this paper, we present the details of our approach in a comprehensive manner, including the salient results.

}, keywords = {Algorithms, Animal, Animals, Biomechanics, Computer-Assisted, Drosophila melanogaster, Escape Reaction, Flight, Image Processing, Video Recording}, issn = {1558-2531}, doi = {10.1109/TBME.2009.2027606}, author = {Zabala, Francisco A and Card, Gwyneth M and Fontaine, Ebraheem I and Dickinson, Michael H and Murray, Richard M} } @article {5758, title = {High-throughput ethomics in large groups of Drosophila.}, journal = {Nature Methods}, volume = {6}, year = {2009}, month = {2009 Jun}, pages = {451-7}, abstract = {

We present a camera-based method for automatically quantifying the individual and social behaviors of fruit flies, Drosophila melanogaster, interacting in a planar arena. Our system includes machine-vision algorithms that accurately track many individuals without swapping identities and classification algorithms that detect behaviors. The data may be represented as an ethogram that plots the time course of behaviors exhibited by each fly or as a vector that concisely captures the statistical properties of all behaviors displayed in a given period. We found that behavioral differences between individuals were consistent over time and were sufficient to accurately predict gender and genotype. In addition, we found that the relative positions of flies during social interactions vary according to gender, genotype and social environment. We expect that our software, which permits high-throughput screening, will complement existing molecular methods available in Drosophila, facilitating new investigations into the genetic and cellular basis of behavior.

}, keywords = {Animal, Animals, Artificial Intelligence, Automated, Behavior, Computer-Assisted, Drosophila melanogaster, Humans, Image Interpretation, Monitoring, Movement, Pattern Recognition, Physiologic, Posture, Social Behavior}, issn = {1548-7105}, doi = {10.1038/nmeth.1328}, author = {Branson, Kristin and Robie, Alice A and Bender, John and Perona, Pietro and Dickinson, Michael H} } @article {2357, title = {A modular display system for insect behavioral neuroscience.}, journal = {Journal of Neuroscience Methods}, volume = {167}, year = {2008}, month = {2008 Jan 30}, pages = {127-39}, abstract = {

Flying insects exhibit stunning behavioral repertoires that are largely mediated by the visual control of flight. For this reason, presenting a controlled visual environment to tethered insects has been and continues to be a powerful tool for studying the sensory control of complex behaviors. To create an easily controlled, scalable, and customizable visual stimulus, we have designed a modular system, based on panels composed of an 8 x 8 array of individual LEDs, that may be connected together to {\textquoteright}tile{\textquoteright} an experimental environment with controllable displays. The panels have been designed to be extremely bright, with the added flexibility of individual-pixel brightness control, allowing experimentation over a broad range of behaviorally relevant conditions. Patterns to be displayed may be designed using custom software, downloaded to a controller board, and displayed on the individually addressed panels via a rapid communication interface. The panels are controlled by a microprocessor-based display controller which, for most experiments, will not require a computer in the loop, greatly reducing the experimental infrastructure. This technology allows an experimenter to build and program a visual arena with a customized geometry in a matter of hours. To demonstrate the utility of this system, we present results from experiments with tethered Drosophila melanogaster: (1) in a cylindrical arena composed of 44 panels, used to test the contrast dependence of object orientation behavior, and (2) above a 30-panel floor display, used to examine the effects of ground motion on orientation during flight.

}, keywords = {Animal, Animals, Behavior, Computer-Assisted Instruction, Drosophila, Flight, Imaging, Motion, Orientation, Photic Stimulation, Software, Three-Dimensional}, issn = {0165-0270}, doi = {10.1016/j.cub.2010.06.072}, author = {Reiser, Michael B and Dickinson, Michael H} } @article {2169, title = {Visually mediated motor planning in the escape response of Drosophila.}, journal = {Current Biology}, volume = {18}, year = {2008}, month = {2008 Sep 9}, pages = {1300-7}, abstract = {

A key feature of reactive behaviors is the ability to spatially localize a salient stimulus and act accordingly. Such sensory-motor transformations must be particularly fast and well tuned in escape behaviors, in which both the speed and accuracy of the evasive response determine whether an animal successfully avoids predation [1]. We studied the escape behavior of the fruit fly, Drosophila, and found that flies can use visual information to plan a jump directly away from a looming threat. This is surprising, given the architecture of the pathway thought to mediate escape [2, 3]. Using high-speed videography, we found that approximately 200 ms before takeoff, flies begin a series of postural adjustments that determine the direction of their escape. These movements position their center of mass so that leg extension will push them away from the expanding visual stimulus. These preflight movements are not the result of a simple feed-forward motor program because their magnitude and direction depend on the flies{\textquoteright} initial postural state. Furthermore, flies plan a takeoff direction even in instances when they choose not to jump. This sophisticated motor program is evidence for a form of rapid, visually mediated motor planning in a genetically accessible model organism.

}, keywords = {Animal, Animals, Drosophila melanogaster, Escape Reaction, Extremities, Flight, Motor Activity, Motor Cortex, Visual Perception}, issn = {0960-9822}, doi = {10.1016/j.cub.2008.07.094}, author = {Card, Gwyneth and Dickinson, Michael H} } @article {2356, title = {The role of visual and mechanosensory cues in structuring forward flight in Drosophila melanogaster.}, journal = {The Journal of Experimental Biology}, volume = {210}, year = {2007}, month = {2007 Dec}, pages = {4092-103}, abstract = {

It has long been known that many flying insects use visual cues to orient with respect to the wind and to control their groundspeed in the face of varying wind conditions. Much less explored has been the role of mechanosensory cues in orienting insects relative to the ambient air. Here we show that Drosophila melanogaster, magnetically tethered so as to be able to rotate about their yaw axis, are able to detect and orient into a wind, as would be experienced during forward flight. Further, this behavior is velocity dependent and is likely subserved, at least in part, by the Johnston{\textquoteright}s organs, chordotonal organs in the antennae also involved in near-field sound detection. These wind-mediated responses may help to explain how flies are able to fly forward despite visual responses that might otherwise inhibit this behavior. Expanding visual stimuli, such as are encountered during forward flight, are the most potent aversive visual cues known for D. melanogaster flying in a tethered paradigm. Accordingly, tethered flies strongly orient towards a focus of contraction, a problematic situation for any animal attempting to fly forward. We show in this study that wind stimuli, transduced via mechanosensory means, can compensate for the aversion to visual expansion and thus may help to explain how these animals are indeed able to maintain forward flight.

}, keywords = {Animal, Animal Structures, Animals, Cellular, Cues, Drosophila melanogaster, Female, Flight, Magnetics, Mechanotransduction, Orientation, Photic Stimulation, Regression Analysis, Saccades, Visual Fields, Visual Perception, Wind}, issn = {0022-0949}, doi = {10.1016/j.cub.2010.06.072}, author = {Budick, Seth A and Reiser, Michael B and Dickinson, Michael H} } @article {48655, title = {High-speed pollen release in the white mulberry tree, Morus alba L.}, journal = {Sexual Plant Reproduction}, volume = {19}, year = {2006}, month = {2006 Mar}, pages = {19-24}, abstract = {

Anemophilous plants described as catapulting pollen explosively into the air have rarely attracted detailed examination. We investigated floral anthesis in a male mulberry tree with high-speed video and a force probe. The stamen was inflexed within the floral bud. Exposure to dry air initially resulted in a gradual movement of the stamen. This caused fine threads to tear at the stomium, ensuring dehiscence of the anther, and subsequently enabled the anther to slip off a restraining pistillode. The sudden release of stored elastic energy in the spring-like filament drove the stamen to straighten in less than 25\ μs, and reflex the petals to velocities in excess of half the speed of sound. This is the fastest motion yet observed in biology, and approaches the theoretical physical limits for movements in plants.

}, doi = {10.1007/s00497-005-0018-9}, author = {Taylor, Philip E and Card, Gwyneth M and House, James and Dickinson, Michael H and Flagan, Richard C} } @article {2360, title = {A test bed for insect-inspired robotic control.}, journal = {Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences}, volume = {361}, year = {2003}, month = {2003 Oct 15}, pages = {2267-85}, abstract = {

Flying insects are remarkable examples of sophisticated sensory-motor control systems. Insects have solved the fundamental challenge facing the field of mobile robots: robust sensory-motor mapping. Control models based on insects can contribute much to the design of robotic control systems. We present our work on a preliminary robotic control system inspired by current behavioural and physiological models of the fruit fly, Drosophila melanogaster. We designed a five-degrees-of-freedom robotic system that serves as a novel simulation/mobile robot hybrid. This design has allowed us to implement a fly-inspired control system that uses visual and mechanosensory feedback. Our results suggest that a simple control scheme can yield surprisingly robust fly-like robotic behaviour.

}, keywords = {Adaptation, Animal, Automated, Biological, Biomimetics, Computer Simulation, Equipment Design, Feedback, Flight, Models, Orientation, Pattern Recognition, Physiological, Pilot Projects, Robotics, Space Perception, Visual}, issn = {1364-503X}, doi = {10.1016/j.cub.2010.06.072}, author = {Reiser, Michael B and Dickinson, Michael H} }