Biology subjects

Sane, S. P.

Publications and source records attributed to Sane, S. P..

17 recordsLinked to original sources

bioRxiv2026

The control of targeted jumps in nymphal praying mantises

Arboreal insects have developed various strategies to navigate their discontinuous habitats. Many insects, including leafhoppers, katydids, and praying mantises, exhibit the ability to actively leap across their leafy platforms and land on a distant substrate. This behavior is especially important for non-winged insects, including nymphal forms of winged insects, which cannot fly between these substrates. To make a targeted jump, an animal must first orient towards the target, estimate the target distance and angular location, and jump with the appropriate take-off speeds and angles to land on their intended substrate. In three-dimensional space, jumping from one point to another requires estimating distance, as well as azimuthal and elevational angles. Jumping insects such as mantises typically reorient their bodies on the substrate to align with the azimuthal direction of the target. This behavior effectively reduces the task to a two-dimensional problem, in which they must estimate only the distance to the target and its elevational angle. Many insects, including praying mantises, perform rhythmic lateral head movements called peering before performing a targeted jump. Although previous studies suggest that mechanisms such as motion parallax while peering are used for distance estimation, the full repertoire of behaviors that enable mantises to jump to arbitrarily located substrates remains unclear. We hypothesized that mantises have distinct behaviors for distance and elevation angle estimation, which enable them to independently modulate their take-off speeds and angles before jumping. To test this hypothesis, we developed behavioral assays in which mantises were placed on a launch platform and jumped to a target platform positioned at variable distances and angles. Using this apparatus, we filmed the jumps of Giant Asian mantis nymphs (Hierodula spp.) with high-speed videography and tracked body parts to quantify take-off speed and angle. Because mantis jumps are ballistic, their trajectories can be modeled as projectile motion. Our results indicate that mantises estimate target distance and elevation angle using two separate behavioral strategies: distance is assessed through peering maneuvers that generate motion parallax, whereas elevation angle is determined through visual fixation of the target accompanied by specific postural adjustments. By combining these behaviors, mantises modulate the magnitude and direction of propulsive force to achieve successful jumps.

zoology↗

bioRxiv2026

Free-flight kinematics of soldier flies during headwind gust perturbations

Large commercial and military aircraft can operate in a wide range of turbulent conditions, except during extreme weather events such as cyclones. Smaller man-made vehicles, such as micro aerial vehicles (MAVs) and nano aerial vehicles (NAVs), are significantly more sensitive to routine environmental wind fluctuations, making them difficult to control. In contrast, insects exhibit remarkable stability in naturally gusty conditions. Despite this, few studies have systematically investigated the impact of gusts and turbulence on insect flight performance. To address this gap and to gain fundamental insights into insect flight stability under gusty conditions, we examined the flight of freely flying black soldier flies subjected to a discrete head-on aerodynamic gust in a controlled laboratory environment. Flight motions were recorded using two high-speed cameras, and body and wing kinematics were analyzed across 14 distinct cases. In response to the gust, we observed consistent features across the cases: (1) asymmetry in wing stroke amplitude, (2) large changes in body roll angle--up to 160{degrees}--occurring over approximately two wing beats ([~]20 ms) with recovery over [~]9 wing beats, (3) transient pitch-down attitude, and (4) deceleration in the flight direction. These rapid responses, combining passive and active control mechanisms, provide insight into the flight control strategies employed by insects. The findings offer valuable guidance for the design of MAVs and NAVs capable of robustly responding to gusts and unsteady airflow in natural environments.

animal behavior and cognition↗

bioRxiv2025

Caste-specific processing of construction pheromones in mound-building termites

Mound-building termites construct massive structures from soil. These structures contain intricate, interconnected passageways linking multiple chambers and atria, which house the brood and fungus gardens that support wood digestion, while also enabling efficient movement of termites. Remarkably, the major and minor workers who build these structures in their dark, subterranean milieu lack image-forming eyes. Coordinated construction on such a scale requires close communication among thousands of individuals. How do termites communicate and coordinate their activity within the mound? Previous studies have shown that communication between termites is mediated by a range of pheromones. A prominent hypothesis, the stigmergy hypothesis, suggests that termites communicate with their nestmates indirectly, by embedding chemical signals in the soil. We developed a choice assay to measure termite attraction to soil containing termite-deposited cues, offering a choice between soil from a repair site and unprocessed control soil. Using physical and chemical extraction methods, we removed volatile and non-volatile components and then measured termite attraction to the treated soils. In these experiments, termites preferred soil from their own mounds repair site over surrounding soil, indicating the presence of embedded pheromones. Of these, the non-volatile components could elicit responses to soil preserved for long periods of time. When extracted and added exogenously, these pheromones made unprocessed soil attractive to termites. Major and minor workers responded to volatile and non-volatile cues differently, indicating caste-specific responses to pheromones. These data show that termites use soil as a medium for communication, consistent with the stigmergy hypothesis. SignificanceMound-building termites achieve the collective construction of elaborate structures through finely tuned coordination of their building behaviors. Lacking image-forming eyes, they rely heavily on a sophisticated chemical communication system by embedding pheromones in the soil that their nestmates sense and interpret, to coordinate behavior. To investigate this communication system, we conducted a series of experiments using a novel choice assay which measures the behavioural responses of termites to pheromone cues in the soil. These pheromones contain volatile and non-volatile components to which the termites respond in a caste-specific manner. The non-volatile components elicit responses over a very long period. Our findings provide new insights into the chemical communication that drives collective behavior in social termites, with implications for collective robotics.

zoology↗

bioRxiv2025

Dynamics of mound repair behavior in termites

Termites of the species Odontotermes obesus are found widely across the Indian peninsula. Their presence is visible due to the large over-ground mounds that they build across the landscape. These mounds house their entire colony, including major and minor workers, soldiers, the queen and king, and their brood. In addition, the termites also farm a specific variety of fungus within the mounds, which helps them break down the cellulose-rich food. The precise function of the mound architecture is the subject of some debate, and it has been argued that its structure serves physiological functions including thermoregulation or gas exchange for the entire colony. We hypothesized that if the mound structure indeed serves an important function, termites must be able to sense and repair any injury to their mound structure. To test this hypothesis, we created a hole in the mound wall and observed the dynamics of ensuing breach repair. The breach is quickly detected and repaired by the termites along a consistently sigmodial pattern involving the exponential recruitment of termites during the initial phases of repair, and a derecruitment of termites in the final phases. This behavior provides us with an assay to investigate various phenomena pertaining to mound-building, and to examine the sensory cues involved in detection and repair of the mound. From the basic considerations about the stimuli involved, we developed a logistic model to describe breach repair behavior, highlighting the critical role of a systemic cue in initiating this response. Through a series of experiments utilizing various behavioral assays, we identified the presence of light as this systemic cue that triggers mound repair. When light enters the mound, it triggers construction activity in termites, even though the major and minor workers responsible for repairs do not have image-forming eyes. This suggests that termites detect light through an extraocular mechanism

animal behavior and cognition↗

bioRxiv2025

Testing the gearbox hypothesis for insect flight control

Sustained flight in flies requires wing movements at frequencies ranging between 100-1000 Hz, powered by asynchronous flight muscles whose contraction rate exceeds direct neural stimulation. These muscles attach to the thoracic walls in an indirect flight muscle (IFM) configuration, generating thoracic deformations that drive wing flapping, while smaller steering muscles adjust wing kinematics stroke-by-stroke. The wings articulate with the thorax via the wing hinge, in which the radial stop (RS) and a grooved pleural wing process (PWP) interact to form a mechanical "gearbox" system, proposed to modulate wingbeat amplitude during maneuvering. Supporting this gearbox hypothesis, previous studies observed close RS-PWP interactions during fictive turns in tethered flies. An alternative, though not exclusive, hypothesis suggests that steering muscles govern wingbeat amplitude modulation. However, the gearbox hypothesis had not been rigorously tested in freely flying insects. Here, we first assessed the morphological diversity of the RS-PWP-Pterale C complex across Diptera using scanning electron microscopy and found substantial variation, particularly in PWP morphology. We next tested gearbox function by bilaterally ablating the PWP in freely flying houseflies (Musca domestica), which were released into an L-shaped arena requiring 90{degrees} yaw turns. Kinematic analyses revealed no significant differences between control and PWP-ablated flies across various wing and body parameters during yaw turns. Both groups could differentially modulate wingbeat amplitude during turns, a key mechanism for yaw torque generation. These findings indicate that the PWP is not essential for wingbeat amplitude modulation, and suggest that steering muscles may primarily control amplitude control during manuevers. Our results challenge the gearbox hypothesis and underscore the flexibility of the dipteran flight control system.

zoology↗

bioRxiv2024

Encoding of antennal position and velocity by the Johnstons organ in hawkmoths

Insect antennae function as versatile, multimodal sensory probes in diverse behavioural contexts. In addition to their primary role as olfactory organs, they serve essential mechanosensory functions across insects, including auditory perception, vestibular feedback, airflow detection, gravity sensing, and tactile sensation. These diverse functions are facilitated by the mechanosensory Johnstons organ (JO), located at the joint between the second antennal segment, known as the pedicel, and the flagellum. The pedicel-flagellum joint lacks muscles which means that the Johnstons organs can perceive only passive deflections of the flagellum. Earlier work which characterized the sensitivity and short response time of the sensory units of JO in hawkmoths, showed that their sensitivity to a broad frequency range is range-fractionated. This vastly expands the functional repertoire of the JO. However, it is not clear what components of antennal kinematics are encoded by the JO. Here, we conducted experiments to test the hypothesis that JO neurons encode the position and velocity of angular movements of the flagellum. We recorded intracellularly from the axons of primary sensory neurons of JO while stimulating it with ramp-and-hold stimuli in which antennal position or antennal angular velocity was maintained at various constant values. Our study shows that JO neurons encode angular velocity and position of the antenna in their response. We also characterized the neural adaptation of the responses to angular velocities and positions. A majority of neurons were sensitive to a movement in the ventrad direction, in the direction of gravity. The adaptation and the directional response properties give rise to a nonlinear hysteresis-like response. Together, these findings highlight the neurophysiological basis underlying the functional versatility of the JO.

neuroscience↗

bioRxiv2024

Structure of the Femoral Chordotonal Organ in the Oleander hawkmoth, Daphnis nerii

Insect legs serve as crucial organs for locomotion and also act as sensory probes into the environment. They are involved in several complex movements including walking, jumping, prey capture, manipulation of objects, and self-grooming. These behaviours require continuous modulation of motor output through mechanosensory feedback which is provided by numerous mechanosensors located on the cuticle and within the soft tissue. A key mechanosensory organ in the insect leg, the femoral chordotonal organ (FeCO), detects movements of the femoro-tibial joint. This organ is multifunctional and senses both self-generated movements (proprioception) and external stimuli (exteroception). Movements of the tibia alter the length of FeCO, which activates the embedded mechanosensory neurons. Due to the mechanical nature of these stimuli, the structure and material properties of the FeCO are crucial for their function, alongside neural encoding properties. Here, as a first step towards understanding how its structure modulates its function, we characterized the morphology and anatomy of FeCO in the hawkmoth Daphnis nerii. Using a combination of computed micro-tomography, neuronal dye fills and confocal microscopy, we describe the structure of FeCO and the location, composition and central projections of FeCO neurons. FeCO is located in the proximal half of the femur and is composed of the ventral (vFeCO) and dorsal scoloparia (dFeCO) which vary vastly in their sizes and the number of neurons they house. The arrangement of neurons within dFeCO follows a decreasing size gradient in the proximo-distal axis. The characteristic accessory structures of chordotonal organs, the scolopales, significantly differ in their sizes when compared between the two scoloparia. FeCO neurons project to the central nervous system and terminate in the respective hemiganglia. Using these morphological data, we propose a mechanical model of FeCO, which can help us understand several FeCO properties relating to its physiological function.

neuroscience↗

bioRxiv2024

Mechanosensory cephalic bristles mediate rapid flight initiation in endothermic hawkmoths

Endothermic insects including bees, butterflies, and moths need to warm up their flight muscles before taking flight. For instance, diurnal butterflies bask in the sun to heat their flight muscles, whereas nocturnal hawkmoths display a pre-flight shivering behavior in which small-amplitude wing movements cause flight muscles to warm up, eventually generating large-amplitude wing motion for flight. The time required for warm-up puts such insects at a considerable risk if they need to rapidly escape from predators. Here, we show that upon experiencing a sudden air-puff on the head, hawkmoths rapidly initiate flight bypassing the pre-flight shivering phase. This response is mediated by mechanosensory cephalic bristles that are buried under the scales on their head. Cephalic bristle mediated flight entails a stereotypic triggering of various flight-related reflexes including antennal positioning, foreleg extension, wing movement, and abdominal flexion. Some mechanosensory neurons underlying cephalic bristles arborize in the subesophageal zone (SEZ) and antennal motor and mechanonsensory center (AMMC), whereas most arborize in pro-, meso- and meta-thoracic ganglia which contain the motor circuitry for foreleg motion, flight, and abdominal flexion. Thermal recordings revealed that large-amplitude wing motion following cephalic bristle-stimulation occurs at lower thoracic temperatures than required for voluntary flight. Electromyogram recordings from steering and indirect flight muscles show significant variability in activation latency in response to cephalic bristle stimulus. The range of latency values among different muscles overlaps, suggesting that cephalic bristle stimulation activates steering muscles, thereby generating high-amplitude wing movement at lower thoracic temperatures. Concomitant activation of the indirect flight muscles initiates thoracic warm-up in preparation for longer flight. Thus, akin to locusts, the cephalic bristle system in hawkmoths rapidly triggers flight upon sensing danger, ensuring swift escape from potential threats.

neuroscience↗

bioRxiv2023

The motor apparatus of head movements in the Oleander hawkmoth (Daphnis nerii, Lepidoptera)

Head movements of insects play a vital role in diverse locomotory behaviors including flying and walking. Because insect eyes move minimally within their sockets, their head movements are essential to reduce visual blur and maintain a stable gaze. As in most vertebrates, gaze stabilization behavior in insects requires integration of both visual and mechanosensory feedback by the neck motor neurons. Whereas visual feedback is derived from the optic flow over the retina of their compound eyes, mechanosensory feedback is derived from their organs of balance, similar to the vestibular system in vertebrates. In Diptera, vestibular feedback is derived from the halteres - modified hindwings that evolved into mechanosensory organs - and is integrated with visual feedback to actuate compensatory head movements. However, non-Dipteran insects including Lepidoptera lack halteres. In these insects, vestibular feedback is obtained from the antennal Johnstons organs but it is not well-understood how it integrates with visual feedback during head movements. Indeed, although head movements are well-studied in flies, the underlying motor apparatus in non-Dipteran taxa has received relatively less attention. As a first step towards understanding compensatory head movements in the Oleander hawkmoth Daphnis nerii, we image the anatomy and architecture of their neck joint sclerites and muscles in using X-ray microtomography, and the associated motor neurons using fluorescent dye fills and confocal microscopy. Based on these morphological data, we propose testable hypotheses about the putative function of specific neck muscles during head movements, which can shed light on their role in neck movements and gaze stabilization.

neuroscience↗

bioRxiv2022

Small-amplitude head oscillations result from a multimodal head stabilization reflex in hawkmoths

In flying insects, head stabilization is an important reflex which helps to reduce motion blur during fast aerial maneuvers. This reflex is multimodal and requires the integration of visual and antennal mechanosensory feedback, each operating as a negative-feedback control loop. As in any negative-feedback system, the head stabilization system possesses inherent oscillatory dynamics that depends on the rates and latencies of the sensorimotor components constituting the reflex. Consistent with this expectation, we observed small amplitude oscillations in the head motion (or head wobble) of the Oleander hawkmoth Daphnis nerii. We show here that these oscillations emerge from the inherent dynamics of the multimodal reflex that underlies gaze stabilization, and the amplitude of the head wobble is a function of both the visual feedback and antennal mechanosensory feedback from the Johnstons organs. The head wobble is thus an outcome of a multimodal, dynamically-stabilized head positioning reflex.

neuroscience↗

bioRxiv2022

Integration of visual and antennal mechanosensory feedback during head stabilization in hawkmoths

During flight maneuvers, insects exhibit compensatory head movements which are essential for stabilizing the visual field on their retina, reducing motion blur, and supporting visual self-motion estimation. In Diptera, such head movements are mediated via visual feedback from their compound eyes that detect retinal slip, as well as rapid mechanosensory feedback from their halteres - the modified hindwings that sense the angular rates of body rotations. Because non-Dipteran insects lack halteres, it is not known if mechanosensory feedback about body rotations plays any role in their head stabilization response. Diverse non-Dipteran insects are known to rely on visual and antennal mechanosensory feedback for flight control. In hawkmoths, for instance, reduction of antennal mechanosensory feedback severely compromises their ability to control flight. Similarly, when the head movements of freely-flying moths are restricted, their flight ability is also severely impaired. The role of compensatory head movements as well as multimodal feedback in insect flight raises an interesting question: in insects that lack halteres, what sensory cues are required for head stabilization? Here, we show that in the nocturnal hawkmoth Daphnis nerii, compensatory head movements are mediated by combined visual and antennal mechanosensory feedback. We subjected tethered moths to open-loop body roll rotations under different lighting conditions, and measured their ability to maintain head angle in the presence or absence of antennal mechanosensory feedback. Our study suggests that head stabilization in moths is mediated primarily by visual feedback during roll movements at lower frequencies, whereas antennal mechanosensory feedback is required when roll occurs at higher frequency. These findings are consistent with the hypothesis that control of head angle results from a multimodal feedback loop that integrates both visual and antennal mechanosensory feedback, albeit at different latencies. At adequate light levels, visual feedback is sufficient for head stabilization. However, under dark conditions, antennal mechanosensory feedback is essential for the control of head movements. HighlightsO_LIVisual feedback contributes to head stabilization primarily during slower body rotation in hawkmoths. C_LIO_LIAntennal mechanosensors contribute to head stabilization primarily during faster body roll. C_LIO_LIAntennal mechanosensory feedback in head stabilization is mediated via Johnstons organ. C_LIO_LIRestricting head movements affects flight control. C_LI

animal behavior and cognition↗

bioRxiv2021

Generating controlled gusts using vortex rings

The control and stability of flying and swimming animals is typically determined by measuring their responses to discrete gust perturbations. For the rigorous measurement and analysis of such responses, it is necessary to generate gusts that are precise, controllable and repeatable. Here, we present a method to generate discrete gusts under laboratory conditions using a vortex ring. Unlike other methods of gust generation, the vortex ring can be well characterized and is highly controllable. We first outline the theoretical basis for the design of a gust generator, and then describe an apparatus that we developed to generate discrete gusts. As a case study, we tested the efficacy of this method on freely-flying soldier flies Hermetia illucens. The method described here can be used to study diverse phenomena ranging from natural flight and swimming in insects, birds, bats and fishes, to the artificial flight of drones and micro-aerial vehicles.

bioengineering↗

bioRxiv2020

Design and development of a vortex ring generator to study the impact of the ring as a gust

We present a simple method to generate discrete aerodynamic gust under controlled laboratory condition in the form of a vortex ring which, unlike conventional methods of perturbation, is well studied and highly controllable. We characterized the flow properties of the vortex ring using flow visualization and novel light bead method. Reynolds number of the vortex ring, based on its average propagation velocity and nozzle exit diameter, was 16000. We demonstrate this method by studying the impact of head-on gust on freely flying soldier flies, Reynolds number of which, based on its wingtip velocity and mean wing chord, was 1100. We also present simple theoretical models to characterize the vortex ring based on generating conditions. The device can also be used to generate continuous gust in any direction and can be applied, in general, to study the gust response of natural fliers and swimmers, man-made micro aerial vehicles and aquatic plant lives.

bioengineering↗

bioRxiv2020

The coupled dual-oscillator model of wing and haltere motion in flies

The mechanics of Dipteran thorax is dictated by a network of exoskeletal linkages which, when deformed by flight muscles, generate coordinated wing movements. In Diptera, forewings power flight, whereas hindwings have evolved into specialized halteres which provide rapid mechanosensory feedback for flight stabilization. Although actuated by independent muscles, wing-haltere motion is precisely phase-coordinated at high frequencies. Because wingbeat frequency is a product of wing-thorax resonance, wear-and-tear of wings or thorax should impair flight ability. Here, we show that wings and halteres are independently-driven, linked, coupled oscillators. We systematically reduced wing length in flies and observed how wing-haltere synchronization was affected. The wing-wing system is a strongly-coupled oscillator, whereas wing-haltere system is weakly-coupled through mechanical linkages which synchronize phase and frequency. Wing-haltere link is unidirectional; altering wingbeat frequency affects haltere frequency, but not vice-versa. Exoskeletal linkages are thus key morphological features of Dipteran thorax, ensuring robust wing-haltere synchrony despite wing damage.

evolutionary biology↗

bioRxiv2018

Visual control of landing maneuvers in houseflies on vertical and inverted surfaces

Landing maneuvers in flies are complex behaviors that may be conceptually decomposed into a sequence of modular behaviors such as body deceleration, extension of legs, and body rotations which are coordinated to ensure controlled touchdown. The composite nature of these behaviors means that there is variability in the kinematics of landing maneuvers, making it difficult to identify the general rules that govern this behavior. Many previous studies have relied on tethered preparations to study landing behaviors, but tethering constrains some behavioral modules to operate in an open feedback control loop while others remain in closed-loop, thereby inducing experimental artefacts. On the other hand, freely flying insects are hard to precisely control, which may also increase behavioral variability. One approach towards understanding the general rules underlying landing behavior is to determine the common elements of landing kinematics on surfaces that are oriented in different ways. We conducted a series of experiments in which the houseflies, Musca Domestica, were lured to specific visual targets on either vertical or inverted horizontal substrates. These conditions elicited landing behaviors in the flies that could be captured accurately using multiple high-speed video cameras. We filmed the houseflies landing on surfaces oriented along two directions: vertical (vertical landings), and upside down (inverted landings). Our experiments reveal that flies that are able to land feet-first in a controlled manner must satisfy specific criteria, failing which their landing performance is compromised causing their heads to bump into the surface during landing. Flies landing smoothly on both surfaces initiate deceleration at approximately fixed distances from the substrate and in direct proportion to the component of flight velocity normal to the landing surface. The ratio of perpendicular distance to the substrate and velocity at the onset of deceleration was conserved, despite the large differences in the mechanics of the vertical vs. inverted landings. Flies extend their legs independently of distance from the landing surface or their approach velocity normal to the surface, regardless of the orientation of the landing substrate. Together, these results show that the visual initiation of deceleration is robust to orientation of the landing surface, whereas the initiation of leg-extension may be context-dependent and variable which allows flies to land on substrates of various orientations in a versatile manner. These findings may also be of interest to roboticists that are interested in developing flapping robots that can land on surfaces of different orientations.

animal behavior and cognition↗

bioRxiv2018

Independent control of slow and fast flight manoeuvres in insects: the roles of vision and antennal mechanoreception

Flying animals need constant sensory feedback about their body position and orientation for flight control. The visual system provides essential but slow feedback. In contrast, mechanosensory channels can provide feedback at much shorter timescales. How the contributions from these two senses are integrated remains an open question in most insect groups. In Diptera, fast mechanosensory feedback is provided by organs called halteres, and is crucial for the control of rapid flight manoeuvres, while vision controls manoeuvres in lower temporal frequency bands. Here we have investigated the visual-mechanosensory integration in an insect which lacks halteres: the hawkmoth Macroglossum stellatarum. They represent a large group of insects that use Johnstons organs in their antennae to provide mechanosensory feedback on perturbations in body position. High-speed videos of freely-flying hawkmoths hovering at stationary or oscillating artificial flowers showed that positional fidelity during flight was reduced in flagella ablated animals, but was recovered after flagella re-attachment. Our experiments show that antennal mechanosensory feedback specifically mediates fast flight manoeuvres, but not slow ones. Differences in the latency of visual feedback (in different light intensities) affected all antennal conditions equally, suggesting there was no compensatory interaction between antennal and visual feedback under the tested conditions. These results establish the importance of antennal mechanosensors in providing rapid mechanosensory feedback for finer control of flight manoeuvres, acting in parallel to visual feedback.

neuroscience↗

bioRxiv2017

Odor source localization in complex visual environments by fruit flies

Flying insects routinely forage in complex and cluttered sensory environments. Their search for a food or a pheromone source typically begins with a whiff of odor, which triggers a flight response, eventually bringing the insect in the vicinity of the odor source. The precise localization of an odor source, however, requires the use of both visual and olfactory modalities, aided by air currents that trap odor molecules into turbulent plumes, which the insects track. Here, we investigated odor tracking behavior in fruit flies (Drosophila melanogaster) presented with low- or high-contrast visual landmarks, which were either paired with or separate from an attractive odor cue. These experiments were conducted either in a gentle air stream which generated odor plumes, or in still air in which odor dissipates uniformly in all directions. The trajectories of the flies revealed several novel features of their odor-tracking behavior in addition to those that have been previously documented (e.g. cast- and-surge maneuvers). First, in both moving and still air, odor-seeking flies rely on the co-occurrence of visual landmarks with olfactory cues to guide them to putative odorant objects in the decisive phase before landing. Second, flies abruptly decelerate when they encounter an odor plume, and thereafter steer towards nearby visual objects that had no inherent salience in the absence of odor. This indicates that the interception of an attractive odor increases their salience to nearby high-contrast visual landmarks. Third, flies adopt distinct odor tracking strategies during flight in moving vs. still air. Whereas they weave in and out of plumes towards an odor source when airflow is present, their approach is more gradual and incremental in still air. Both strategies are robust and flexible, and can ensure that the flies reliably find the odor source under diverse visual and airflow environments. Our experiments also indicate the possibility of an olfactory \" working memory\" that enables flies to continue their search even when the olfactory feedback is reduced or absent. Together, these results provide insights into how flies determine the precise location of an odor source.

animal behavior and cognition↗