The Ayali Lab:

Research Interests and
Current Projects

 

Insect locomotion: generation, coordination and control

Neurophysiological and neuroethological characteristics of locust density-dependent phase polymorphism

Locust swarming as a model for the study of animal collective motion

Bioinspiration and biomimetics: Insect-inspired technological innovation

The locust Microbiome: Dynamics and tentative role in locust phase polyphenism

Some further recent projects

Insect locomotion: generation, coordination and control

Animal movements result from the dynamic interplay among neural commands, muscle and body mechanics, and the environment.  It is increasingly evident that a comprehensive understanding of animal locomotion must address the interactions of all these components.

In several recent and current collaborative interdisciplinary research projects we take advantage of the Desert locust, Schistocerca gregaria and the American cockroach, Periplaneta Americana, utilizing different in-vitro as well as intact and semi-intact preparations.

Spatial and temporal aspects of leg coordination and trajectories are independently controlled

Couzin-Fuchs et al., 2015, J. insect physiol. 79: 96-104

A combined experimental and theoretical approach in used to study questions related to the functional organization of central pattern generating circuits, inter-limb coordination during locomotion, the relative role of sensory inputs vs. central circuits in locomotion control, and more.

Phase relationship among motor nerves controlling the legs are dependent on CPGs inter-connectivity and on which ganglion is driving the network             Knebel et al., 2017, Front. Neural Circuits 10:112

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Neurophysiological and neuroethological characteristics of locust density-dependent phase polymorphism

Locust phase polymorphism (or polyphenism) is defined as the ability of some grasshopper species to show within the species, forms or morphs that differ in their morphology as well as their biology, dependent on the population density.

The behavior of individual locusts in the presence of others is a major phase characteristic. A behavioral change is the first noticeable change when previously isolated locusts are crowded. This change facilitates the appearance of the various morphological and physiological phase changes that follow it.

Our knowledge regarding the neural basis of locust phase differences and phase transformation is still very limited

We have previously studied, among other, the role of sexual selection in locust phase-related behavior. We were the first to report neurophysiological correlates of locust behavioral density-dependent phase differences. The role of learning and memory-related mechanisms in locust phase transformation was also demonstrated.

Current work is aimed at further exploring and completing our understanding of this unique and intricate example of environmental-induced plasticity. 

Locust swarming as a model for the study of animal collective motion

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Collective motion is an important biological phenomenon, ubiquitous among different organisms. One of the most interesting, albeit disastrous, examples of collective motion is that of the marching of locusts. These insects swarm in groups of millions, migrating in mass across large distances, devastating natural vegetation and crops.

 

The recent locust situation in large parts of Africa and Asia is yet another reminder of our far from complete understanding of this major pest.

Locust collective motion in the field (top, Israel Negev desert, spring 2013) and in the lab (bottom).                   Ariel  & Ayali. 2015, PLoS Computational Biology, 11(12), e1004522

For many years, we are working to reveal the basis of locust coordinated swarming behavior.  Our research is largely focused on two major directions: The first, behavioral variance and collective motion, specifically, the intricate interactions between individual and group variance and their role in the generation and maintenance of collective behavior. The second, look at the functional aspects of sensorimotor perception and integration in collective behavior, specifically, visual processing and collective motion-related decision making in locust collective motion.

Collaborating partners include, first and foremost, Gil Ariel (Mathematics, Bar-Ilan Univ.), Gal Kaminka and Noa Agmon (Comp. Eng., Bar-Ilan Univ.), Freddie Bruckstein (Comp. Eng., Technion)

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Bioinspiration and biomimetics: Insect-inspired technological innovation

Several recent and ongoing collaborative and interdisciplinary projects are dedicated to the exploration of various insect systems as a source for application in engineering and robotics.

 

A recent effort was aimed at presenting a 2-D caterpillar simulation, which mimics caterpillar locomotion using Assur tensegrity structures, as a first step towards designing a special kind of bio-inspired soft robot. The unique engineering properties of the model, together with the suggested control scheme, provided the model with a controllable degree of softness.


Orki et al.,2012. Bioinspir. Biomim., 7(4): 046006

A collaborative project between Tel Aviv University and ORT Braude College focused on developing a grasshopper-inspired bio-mimetic jumping robot. Studies of the biomechanics and kinematics of locust jumps allowed modeling the jumping mechanism by computer simulation and implementation of the model in a state of the art robotic device.

A 13 cm, 25 gr locust-inspired jumping robot can jump up to 3 m 

Zaitsev et al., 2015, Bioinspir. Biomim. 10:  066012  

A major effort in the lab is the development of locust-inspired swarming robotics. In collaboration with a team of computer engineers at Bar-Ilan University and the Technion, we are implementing knowledge gained from our studies of locust collective motion into the design of a small robotic platform that while demonstrating complete autonomy, will be able to interact with both live locusts and similar robotic devices to generate hybrid biological-technological swarms.  

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The locust Microbiome - Dynamics and tentative role in locust phase polyphenism 

Locusts have been the focus of extensive research efforts, mostly seeking to better understand the mechanisms underlying the locust phenomenon. Although not part of the major research emphasis, some important observations have been accumulated regarding the locust bacterial symbionts and the nature of locust-bacteria interactions.

Locust phase dependent differences in the population dynamics of microbiota

Lavy, et al. 2020. FEMS Microbiology Ecology96(4), fiaa044 

In recent years we have investigated some less visited questions, including that of the effect of density-dependent phase on the locust bacterial composition; The dynamics of bacterial composition in the locust reproductive tract; Whether and how are beneficial symbionts transmitted through successive generations? And more.

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Neural control of locust ventilation behavior and gas exchange motor patterns 

Discontinuous gas exchange (DGE) is a unique and much studied insect gas exchange pattern. This project was aimed at better understanding the complexity of insect respiratory motor activity and its neural control,  focusing on the adaptive value and the mechanistic basis of DGE. A combination of eco-physiological and electro-physiological approaches were utilized in the study of two species of locusts as models (Schistocerca gregaria and Locusta migratoria).

Monitoring in-vitro respiration motor patterns of locust thoracic ganglia, while simultaneously manipulating the intra-tracheal gas environment.  Talal et al., 2019,  J. Exp. Biol., 222, jeb195388 

Neural control of feeding, digestion and ecdysis-related behavior in the locust

The rhythmic output of a central pattern generator networks situated in the stomatogastric nervous system of the locust was studied in much details. The frontal ganglion (~100 cells, see image) constitute the major source of innervation to the locust front gut. We investigated the characteristic neural patterns that can be recorded from nerves leaving the ganglion and from the network's neurons in two very distinct behavioral contexts; feeding and molting (the periodical shedding of the insect's cuticle during metamorphosis). We were interested in the interactions between this neural circuit and other neural centers as well as endocrine factors specific to the different behavioral states.

The effects of light pollution on crickets' behavior

Daily behavioral patterns in all animals largely depend on the natural cycle of day and night. Light pollution, manifested as artificial light at night (ALAN), is a growing problem in our modern world. Recent years have seen increasing awareness and concern regarding the harmful effects of ALAN on all living organisms, including, among other, changes in length and quality of sleep, temporal shifts in activity, and more. The effects of ALAN on insects have been relatively less studied.

Cricket stridulation behavior in the lab (Keren Levy)

Our recent findings (in collaboration with Prof. Anat Barnea, Israel Open Univ.) present the field cricket Gryllus bimaculatus as a suitable model for studying the influence of ALAN on insect behavior. We demonstrate that ecologically relevant ALAN intensities affect the crickets’ locomotion and stridulation motor patterns, with a potential impact on foraging, as well as mating behavior.  

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