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Biology subjects

Ayali, A.

Publications and source records attributed to Ayali, A..

At least 19 recordsLinked to original sources
bioRxiv2026

The Sniffbot: A biohybrid robot for active sensing-based odor localization and discrimination

The detection, identification and localization of volatile compounds are of critical importance for various applications, ranging from gas leak detection to drug and explosive sensing. Current technologies--such as gas chromatography-mass spectrometry and e-noses--are limited by slow analysis, low mobility, and reduced sensitivity and adaptability, making them unsuitable for real-time odor localization in real-world settings. Here, we present Sniffbot: an autonomous, mobile biohybrid robotic sensory system that overcomes these challenges by harnessing the extraordinary olfactory capabilities of the desert locust antenna, an advanced olfactory sensor, that generates odorant-specific electrophysiological responses to numerous odorants. Our Sniffbot platform consists of a compact robotic vehicle onto which we have assembled: (i) a sensing module, comprising a locust antenna and a miniaturized electrophysiology system; (ii) a "sniffing" module, which actively samples air in the environment, creating a timed airflow over the antenna, preventing the antenna from becoming habituated to odorant stimuli; and (iii) a decision-making module that analyzes the sensory input in real time to navigate or identify odors. Sniffbots movements are controlled by an odorant-search algorithm coupled with the sniffing module. This enables Sniffbot to detect and localize odors independently of wind-induced odorant gradients, and thus to be used in challenging windless environments. The Trident, a novel search algorithm, outperforms several commonly used algorithms in localizing the odorant source. We further demonstrate Sniffbots ability to discriminate a target odor among others. Our results demonstrate the potential of augmenting biological sensors with autonomous robotic components for next-generation chemical sensing and environmental monitoring.

bioengineering↗
bioRxiv2025

Biologically-constrained insect models enable realistic simulations and improve biomechanical predictions of locomotion

Animal locomotion emerges from the complex interplay of morphology, neural control, and biomechanics, involving both active and passive elements. Insect have attracted much interest, and a rich ecosystem of computational models exists for insect locomotion. However, while active control mechanisms have been extensively studied, obtaining accurate and useful models remains challenging due to limited understanding of how detailed anatomical constraints and passive biomechanical properties shape movement. To address this, we developed anatomically accurate 3D models of the adult desert locust and mole cricket, two orthopteran insects that share a basic body plan but exhibit strikingly different morphologies linked to their habitats and specialized locomotor behaviors -- jumping in locusts versus subterranean digging in mole crickets. We fine-tuned these models using precise morphometric measurements for each major body segment. Furthermore, we quantified passive joint dynamics through high-speed videography of anesthetized locust, revealing a two-phase return motion and history-dependent resting angles. By integrating these biologically grounded constraints into physical simulations, we significantly narrowed the parameter space, resulting in more realistic simulations. Our approach provides new tools for predicting biologically relevant, yet experimentally challenging variables, such as joint torques and contact forces, which contribute directly to the understanding of the underlying biological phenomena. Moreover, these improved simulations offer valuable insight for designing energy-efficient soft robotic systems.

animal behavior and cognition↗
bioRxiv2025

Multiple locomotion gaits in the mole cricket

Insects are exceptionally robust walkers. Although different species exhibit distinct anatomical and functional specializations, they are also highly adaptive within these constraints. How such adaptations enable insects to efficiently navigate diverse environments and perform mechanical tasks remains far from fully explored. The mole cricket, which dwells underground, is one of the least studied insects, largely due to its cryptic lifestyle. It excels at digging tunnels and exhibits extreme morphological adaptations, particularly its exceptional fossorial forelegs. Its versatile locomotion, above and below ground, makes the mole cricket an attractive model system for studying the biomechanics of insect movement. Here we provide the first quantitative characterization of mole cricket locomotion. Using a tunnel-like arena, we recorded freely-moving insects and analyzed their various locomotion gaits. We identified and described three main modes of locomotion, including a backward-bound gait that has not previously been reported in any insect. To test specific hypotheses regarding form-function relationships and the generation of thrust, we integrated biomechanical modeling and deep reinforcement learning to simulate the observed gaits. Our work opens several future directions, from exploring context-dependent gait transitions to bio-inspired technological innovations.

animal behavior and cognition↗
bioRxiv2024

Six-legged-bound: a newly-described insect gait

Locomotor behavior is a hallmark of animal biology and ecology. Mole crickets constitute a unique group of subterranean insects that present an exceptional model for locomotion-related research. In response to an aversive stimulus from the front, the mole cricket will consistently adopt a unique backwards gait that we have termed backward-bound. This never before reported six-legged gait comprises a cyclic alternation between the middle and hind-leg pairs with left-right in-phase synchronization, while the front legs display noisy and less consistent phase dynamics. This exceptional gait is transient and is usually expressed for up to a dozen cycles. It is employed to distance the animal quickly away from danger. A gait that can be characterized as "forward-bound" is also displayed by the mole cricket, albeit for a much shorter duration (up to two cycles).

animal behavior and cognition↗
bioRxiv2024

Obstacle Negotiation in Female Locust Oviposition Digging

The female locust lays its eggs deep within soft substrate to protect them from predators and provide optimal conditions for successful hatching. During oviposition digging, the females abdomen extends into the ground, guided by a dedicated excavation mechanism at its tip, comprising two pairs of specialized digging valves. Little is known about how these active valves negotiate the various obstacles encountered on their path. In this study, female locusts oviposited their eggs in specialized sand-filled tubes with pre-inserted 3D-printed plastic obstacles. The subterranean route taken by the abdomen and digging valves upon encountering the obstacles was investigated, characterized, and compared to that in control tubes without obstacles. Data were obtained by way of visual inspection, by utilizing Cone Beam Computed Tomography scans in high-definition mode, and by making paraffin casts of the oviposition burrows (after egg hatching). We demonstrate, for the first time, the subterranean navigation ability of the female locusts excavation mechanism and its ability to circumvent obstacles during oviposition. Finally, we discuss the role of active sensory-motor mechanisms versus the passive embodied function of the valves, central control, and decision-making.

animal behavior and cognition↗
bioRxiv2023

When Night Becomes Day: Artificial Light at Night Alters Insect Behavior under Semi-Natural Conditions

Light is the most important Zeitgeber for temporal synchronization in nature. Artificial light at night (ALAN) disrupts the natural light-dark rhythmicity and thus negatively affects animal behavior. However, to date, ALAN research has been mostly conducted under laboratory conditions in this context. Here, we used the field cricket, Gryllus bimaculatus, to investigate the effect of ALAN on insect behavior under semi-natural conditions, i.e., under shaded natural lighting conditions, natural temperature and soundscape. Male crickets were placed individually in outdoor enclosures and exposed to ALAN conditions ranging from <0.01 to 1,500 lx intensity. The crickets stridulation behavior was recorded for 14 consecutive days and nights and their daily activity patterns were analysed. ALAN impaired the crickets stridulation rhythm, evoking a change in the crickets naturally synchronized daily activity period. This was manifested by a light-intensity-dependent increase in the proportion of insects demonstrating an intrinsic circadian rhythm (free-run behavior). This also resulted in a change in the populations median activity cycle period. These ALAN-induced effects occurred despite the crickets exposure to almost natural conditions. Our findings provide further validity to our previous studies on ALAN conducted under lab conditions and establish the deleterious impacts of ALAN on animal behavioral patterns. HighlightsO_LIALAN presents a threat for insect populations and biodiversity C_LIO_LIThe impact of ALAN on insect behavior is mostly studied under laboratory conditions C_LIO_LIWe studied the effects of ALAN on cricket stridulation in semi-natural conditions C_LIO_LIALAN clearly affected the crickets behavior in a light-intensity dependent manner C_LIO_LIThe behavioral effects of ALAN were revealed despite the semi-natural environment C_LIO_LIALAN represents a threat for cricket populations fitness C_LI

animal behavior and cognition↗
bioRxiv2023

Vision-Based Collective Motion: A Locust-Inspired Reductionist Model

Naturally occurring collective motion is a fascinating phenomenon in which swarming individuals aggregate and coordinate their motion. Many theoretical models of swarming assume idealized, perfect perceptual capabilities, and ignore the underlying perception processes, particularly for agents relying on visual perception. Specifically, biological vision in many swarming animals, such as locusts, utilizes monocular non-stereoscopic vision, which prevents perfect acquisition of distances and velocities. Moreover, swarming peers can visually occlude each other, further introducing estimation errors. In this study, we explore necessary conditions for the emergence of ordered collective motion under restricted conditions, using non-stereoscopic, monocular vision. We present a model of vision-based of collective motion for locust-like agents: elongated shape, omni-directional visual sensor parallel to the horizontal plane, and lacking stereoscopic depth perception. The model addresses (i) the non-stereoscopic estimation of distance and velocity, (ii) the presence of occlusions in the visual field. We consider and compare three strategies that an agent may use to interpret partially-occluded visual information at the cost of the computational complexity required for the visual perception processes. Computer-simulated experiments conducted in various geometrical environments (toroidal, corridor, and ring-shaped arenas) demonstrate that the models can result in an ordered or near-ordered state. At the same time, they differ in the rate at which order is achieved. Moreover, the results are sensitive to the elongation of the agents. Experiments in geometrically constrained environments reveal differences between the models and elucidate possible tradeoffs in using them to control swarming agents. These suggest avenues for further study in biology and robotics. Author summarySwarm collective motion is a wide-ranging phenomenon in nature, with applications in multi-agent, multi-robot systems. In most natural swarming species, individuals rely on monocular, non-stereoscopic vision as the key sensory modality for their interactions. For example, the migratory locust (locusta migratoria) displays large swarms of individuals, moving in alignment and relying solely on non-stereoscopic visual perception. Inspired by these locust swarms, we have developed a monocular, non-stereoscopic vision-based model that achieves synchronized motion in a swarm of two-dimensional agents, even with inaccurate estimates of distances and velocities, particularly in the presence of occlusions. We explore three general strategies for handling occlusions, which differ in the requirements they place on the complexity of the visual perception process. We show that strategies may reach a highly ordered motion state but differ in their convergence rate.

animal behavior and cognition↗
bioRxiv2022

Visual processing and collective motion-related decision-making in desert locusts

Collectively moving groups of animals rely on the decision-making of locally interacting individuals in order to maintain swarm cohesion. However, the complex and noisy visual environment poses a major challenge to the extraction and processing of relevant information. We addressed this challenge by studying swarming-related decision-making in desert locust last-instar nymphs. Controlled visual stimuli, in the form of random dot kinematograms, were presented to tethered locust nymphs in a trackball setup, while monitoring movement trajectory and walking parameters. In a complementary set of experiments, the neurophysiological basis of the observed behavioral responses was explored. Our results suggest that locusts utilize filtering and discrimination upon encountering multiple stimuli simultaneously. Specifically, we show that locusts are sensitive to differences in speed at the individual conspecific level, and to movement coherence at the group level, and may use these to filter out non-relevant stimuli. The locusts also discriminate and assign different weights to different stimuli, with an observed interactive effect of stimulus size, relative abundance, and motion direction. Our findings provide insights into the cognitive abilities of locusts in the domain of decision-making and visual-based collective motion, and support locusts as a model for investigating sensory-motor integration and motion-related decision-making in the intricate swarm environment.

animal behavior and cognition↗
bioRxiv2022

Transcriptional response of circadian clock genes to an 'artificial light at night' pulse in the cricket Gryllus bimaculatus

Light is the major signal entraining the circadian clock that regulates physiological and behavioral rhythms in most organisms, including insects. Artificial Light at Night (ALAN) disrupts the natural light-dark cycle and negatively impacts animals at various levels. We simulated ALAN using dim light stimuli and tested their impact on gene expression in the cricket Gryllus bimaculatus, a model of insect physiology and chronobiology. At night, adult LD crickets were exposed for 30 minutes to a light pulse of 2-40 lx. The relative expression of five circadian clock associated genes was compared using qPCR. A dim ALAN pulse elicited tissue-dependent differential expression in some of these genes. The strongest effect was observed in the brain and in the optic lobe, the crickets circadian pacemaker. Expression of opsin-Long Wave (opLW) was upregulated, as well as cryptochrome1-2 (cry), and period (per). Our findings demonstrate that even a dim ALAN exposure may affect insects at the molecular level, underscoring the detrimental impact of ALAN on the circadian clock system.

animal behavior and cognition↗
bioRxiv2021

The Biomechanics of the Locust Ovipositor Valves: a Unique Digging Apparatus

The female locust has a unique mechanism for digging in order to deposit its eggs deep in the ground. It utilizes two pairs of sclerotized valves to displace the granular matter, while extending its abdomen as it propagates underground. This ensures optimal conditions for the eggs to incubate, and provides them with protection from predators. Here, two major axes of operation of the digging valves are identified, one in parallel to the propagation direction of the ovipositor, and one perpendicular to it. The direction-dependent biomechanics of the locust major, dorsal digging valves are quantified and analyzed, under forces in the physiological range and beyond, considering hydration level, as well as the females age, or sexual maturation state. Our findings reveal that the responses of the valves to compression forces in the specific directions change upon sexual maturation to follow their function, and depend on environmental conditions. Namely, in the physiological force range, the valves are resistant to mechanical failure. In addition, mature females, which lay eggs, have stiffer valves, up to roughly nineteen times the stiffness of the pre-mature locusts. The valves are stiffer in the major working direction, corresponding to soil shuffling and compression, compared to the direction of propagation. Hydration of the valves reduces their stiffness but increases their resilience against failure. These findings provide mechanical and materials guidelines for the design of novel non-drilling excavating tools, including 3D-printed anisotropic materials based on composites. Statement of significanceThe female locust lay its eggs underground in order to protect them from predators and to provide them with optimal conditions for hatching. In order to dig into the ground, it uses two pairs of valves: The ventral pair is plugged as a wedge, while the dorsal pair performs the digging of the oviposition tunnel. We study the mechanical response of the digging valves, depending on age, hydration level and direction of operation. Our findings show that during the course of roughly two weeks in the life of the adult female, the digging valves become up to nineteen-fold stiffer against failure, in order to fulfill their function as diggers. While hydration reduces the stiffness, it also increases the resilience against failure and renders the valves unbreakable within the estimated physiological force range and beyond. The digging valves are consistently stiffer in the digging direction than in the perpendicular direction, implying on their form-follows-function design. Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

bioengineering↗
bioRxiv2020

Microbiome-related aspects of locust density-dependent phase transition

Locust plagues are an ancient phenomenon, with references going back to the Old Testament. These swarming pests are notorious for their tendency to aggregate and perform long migrations, consuming vast amounts of vegetation and decimating the cultivated fields on their path. However, when population density is low, locusts will express a solitary, cryptic, non-aggregating phenotype that is not considered as an agricultural pest. Although transition of locusts from the solitary to the gregarious phase has been well studied, the shifts in the locust microbiome composition associated with this phase-transition have yet to be addressed. Here, using 16S rRNA amplicon sequencing, we compared the bacterial composition of solitary desert locusts before and after a crowding-induced phase-transition. Our findings reveal that the microbiome is altered during the phase transition. We also show that this significant change in bacterial composition includes the acquisition of a specific bacterial species - Weissella cibaria (Firmicutes), which has been previously shown to induce aggregation in cockroaches. Our findings led us to hypothesize that the locust microbiome may play a role in inducing aggregation behavior, contributing to the formation and maintenance of a swarm. Employing a mathematical model, we demonstrate the potential evolutionary advantage of inducing aggregation under various environmental conditions; and specifically, when the aggregation-inducing microbe exhibits a relatively high horizontal transmission rate. This is a first description of a previously unknown and important aspect of locust phase transition, demonstrating that the phase shift includes a shift in the gut and integument bacterial composition.

microbiology↗
bioRxiv2020

The maternal foam plug constitutes a reservoir for the desert locust's bacterial symbionts

A hallmark of the desert locusts ancient and deserved reputation as a devastating agricultural pest is that of the long-distance, multi-generational migration of locust swarms to new habitats. The bacterial symbionts that reside within the locust gut comprise a key aspect of its biology, augmenting its immunity and having also been reported to be involved in the swarming phenomenon through the emission of attractant volatiles. However, it is still unclear whether and how these beneficial symbionts are transmitted vertically from parent to offspring. Using comparative 16S rRNA amplicon sequencing and direct experiments with engineered bacteria, we provide here evidence of the vertical transmission of locust gut bacteria. The females perform this activity by way of inoculation of the egg-pods foam plug, through which the larvae pass upon hatching. Furthermore, analysis of the biochemical structure of the foam revealed chitin to be its major component, along with immunity-related proteins such as lysozyme, which could be responsible for the inhibition of some bacteria in the foam while allowing other, more beneficial, strains to proliferate. Our findings reveal a potential vector for the transgenerational transmission of symbionts in locusts, which contributes to the locust swarms ability to invade and survive in new territories.

ecology↗
bioRxiv2020

Collective motion as a distinct behavioral state of the individual

The collective motion of swarms depends on adaptations at the individual level. We explored these and their effects on swarm formation and maintenance in locusts. The walking kinematics of individual insects were monitored under laboratory settings, before, as well as during collective motion in a group, and again after separation from the group. It was found that taking part in collective motion induced in the individual unique behavioural kinematics, suggesting the existence of a distinct behavioural mode that we term a "collective-motion-state". This state, characterized by behavioural adaptation to the social context, is long lasting, not induced by crowding per-se, but only by experiencing collective motion. Utilizing computational models, we show that this adaptability increases the robustness of the swarm. Overall, our findings suggest that collective-motion is not only an emergent property of the group, but also depends on a behavioural mode, rooted in endogenous mechanisms of the individual.

ecology↗
bioRxiv2019

Respiratory gas levels interact to control ventilatory motor patterns in isolated locust ganglia

Large insects actively ventilate their tracheal system even at rest, using abdominal pumping movements, which are controlled by a central pattern generator (CPG) in the thoracic ganglia. We studied the effects of respiratory gases on the ventilatory rhythm by isolating the thoracic ganglia and perfusing its main tracheae with various respiratory gas mixtures. Fictive ventilation activity was recorded from motor nerves controlling spiracular and abdominal ventilatory muscles. Both hypoxia and hypercapnia increased the ventilation rate, with the latter being much more potent. Sub-threshold hypoxic and hypercapnic levels were still able to modulate the rhythm as a result of interactions between the effects of the two respiratory gases. Additionally, changing the oxygen levels in the bathing saline affected ventilation rate, suggesting a modulatory role for haemolymph oxygen. Central sensing of both respiratory gases as well as interactions of their effects on the motor output of the ventilatory CPG reported here indicate convergent evolution of respiratory control among terrestrial animals of distant taxa. Summary statementTight control over respiratory gas supply to the isolated locust CNS reveals interactions of oxygen and carbon dioxide effects on central ventilatory output.

neuroscience↗
bioRxiv2018

Sexual behavior of the desert locust during intra- and inter-phase interactions

Mating and reproduction behaviors and strategies are fundamental aspects of an organisms evolutionary and ecological success. In locusts, intra- as well as inter-phase reproductive interactions among gregarious and solitarious locust populations have a major impact on the locust population dynamics. However, practically all previous work on locust sexual behavior has been limited to the gregarious phase. Here we provide a first detailed description of pre-copulatory behavior of solitarious desert locusts. We compare our findings with those of previous reports of pre-copulatory behavior of gregarious locusts, focusing on the behavioral elements that serve in inter-sex signaling and communication. We also studied inter-phase (mixed pairs) reproductive interactions. Solitarious males were found to invest more in pre-copulatory courtship and signaling compared to their gregarious counterparts; and the solitarious females played a comparatively more dominant role in the inter-sex communication. The solitarious females were also less prone to demonstrate the typical rejection-related behavioral patterns displayed by the gregarious females. As a consequence of the particular characteristic behavior of each phase, the most successful among intra- and inter-phase pairs were gregarious males with solitary females. Least successful were solitary males encountered with gregarious females, indicating a strong asymmetry in inter-phase reproductive interactions. We discuss these results in the context of non-random or assortative mating in locust mixed or sympatric solitarious-gregarious populations.

animal behavior and cognition↗
bioRxiv2018

The subesophageal ganglion modulates locust inter-leg sensory-motor interactions via contralateral pathways

The neural control of insect locomotion is distributed among various body segments. Local pattern-generating circuits at the thoracic ganglia interact with incoming sensory signals and central descending commands from the head ganglia. The evidence from different insect preparations suggests that the subesophageal ganglion (SEG) may play an important role in locomotion-related tasks. In a previous study, we demonstrated that the locust SEG modulates the coupling pattern between segmental leg CPGs in the absence of sensory feedback. Here, we investigated its role in processing and transmitting sensory information to the leg motor centers, and mapped the major related neural pathways. Specifically, the intra- and inter-segmental transfer of leg-feedback were studied by simultaneously monitoring motor responses and descending signals from the SEG. Our findings reveal a crucial role of the SEG in the transfer of intersegmental, but not intrasegmental, signals. Additional lesion experiments, in which the intersegmental connectives were cut at different locations, together with double nerve staining, indicated that sensory signals are mainly transferred to the SEG via the connective contralateral to the stimulated leg. We therefore suggest that, similar to data reported for vertebrates, insect leg sensory-motor loops comprise contralateral ascending pathways to the head and ipsilateral descending ones.

neuroscience↗
bioRxiv2017

The Functional Connectivity between the Locust Leg Pattern Generating Networks and the Subesophageal Ganglion Higher Motor Center

Interactions among different neuronal circuits are essential for adaptable coordinated behavior. Specifically, higher motor centers and central pattern generators (CPGs) induce rhythmic leg movements that act in concert in the control of locomotion. Here we explored the relations between the subesophageal ganglion (SEG) and thoracic leg CPGs in the desert locust. Backfill staining revealed about 300 SEG descending interneurons (DINs) and some overlap with the arborization of DINs and leg motor neurons. In accordance, in in-vitro preparations, electrical stimulation applied to the SEG excited these neurons, and in some cases also induced CPGs activity. Additionally, we found that the SEG regulates the coupling pattern among the CPGs: when the CPGs were activated pharmacologically, inputs from the SEG were able to synchronize contralateral CPGs. This motor output was correlated to the firing of SEG descending and local interneurons. Altogether, these findings point to a role of the SEG in both activating leg CPGs and in coordinating their oscillations, and suggest parallels between the SEG and the brainstem of vertebrates.

neuroscience↗