Biology subjects

Yovel, Y.

Publications and source records attributed to Yovel, Y..

17 recordsLinked to original sources

bioRxiv2026

A two-signal, two-receiver signalling system: Snake mobbing in the Arabian babbler

Mobbing is a collective antipredator behaviour in which animals approach and harass a threat while coordinating signals to alert conspecifics, recruit allies, or deter predators. In group-living Arabian babblers (Argya squamiceps), snake mobbing relies on two signals that differ in receivers: acoustic "zwick" calls inaudible to the snake and visual wing-lift displays perceived by both conspecifics and the snake, raising the question of whether each signal has one receiver or involves a more complex structure. We elicited snake-mobbing events with dummy vipers and recorded babbler groups using a synchronized acoustic camera enabling individual caller identification and postural analysis. We examined mob formation, the effect of group size on signalling, and the interplay between the two signal types. First signalling (recruitment) order was independent of sex, age and rank. Individual call rate decreased as group size increased, supporting the hypotheses of social buffering and predation risk dilution. Mobbing individuals responded faster (with signalling) to a joint visual-acoustic conspecific display and the onset of a visual display than to an acoustic-only signal. When coupled, wing-lifts significantly altered vocal characteristics, decreasing peak frequency and increasing call rate, thus strengthening the acoustic signal. Moreover, calls emitted toward the end of the wing-lift display exhibited a stronger drop in peak frequency. Together, these findings demonstrate the multi-functional role of multimodal mobbing signals during a risky cooperative task balancing social communication and predator deterrence.

animal behavior and cognition↗

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↗

bioRxiv2024

How bats exit a crowded colony when relying on echolocation only - a modeling approach

Bats face a complex navigation challenge when emerging from densely populated roosts, where vast numbers take off at once in dark, confined spaces. Each bat must avoid collisions with walls and conspecifics while locating the exit, all amidst overlapping acoustic signals. This crowded environment creates the risk of acoustic jamming, in which the calls of neighboring bats interfere with echo detection, potentially obscuring vital information. Despite these challenges, bats navigate these conditions with remarkable success. Although bats have access to multiple sensory cues, here we focused on whether echolocation alone could provide sufficient information for orientation under such high-interference conditions. To explore whether and how they manage this challenge, we developed a sensorimotor model that mimics the bats echolocation behavior under high-density conditions. Our model suggests that the problem of acoustic jamming may be less severe than previously assumed. Frequent calls with short inter-pulse intervals (IPI) increase the sensory input flow, allowing integration of echoic information across multiple calls. When combined with simple movement-guidance strategies--such as following walls and avoiding nearby obstacles--this accumulated information enables effective navigation in dense acoustic environments. Together, these findings demonstrate a plausible mechanism by which bats may overcome acoustic interference and underscore the role of signal redundancy in supporting robust echolocation-based navigation. Beyond advancing our understanding of bat behavior, they also offer valuable insights for swarm robotics and collective movement in complex environments.

animal behavior and cognition↗

bioRxiv2024

Female Moths Incorporate Plant Acoustic Emissions into Their Oviposition Decision

Insects rely on plants visual, chemical, tactile, and electrical cues when making various decisions. A recent study demonstrated that dehydrated plants emit ultrasonic sounds within the auditory sensitivity range of many moth species. In this study, we sought to determine whether insects also rely on plant acoustic signals when making decisions. We investigated whether female moths rely on ultrasonic clicks which are typically produced by dehydrated plants when deciding where to oviposit. In the absence of an actual plant, the moths indeed preferred to lay their eggs in proximity to acoustic signals which represent dehydrating plants. Tracking the moths behavior prior to the decision showed that they examined both sides of the arena and gradually spent more time on the acoustic-playback side. Interestingly, when actual plants were added to the arena, the oviposition preference was reversed and the moths preferred silent plants, which is in accordance with their a-priori preference for hydrated plants. Deafening the moths eliminated their preference, confirming that the choice was based on hearing. Moreover, the presence of male moths including their auditory signals did not affect their oviposition decision, suggesting that the response was specific to plant sound emissions. We reveal evidence for a first acoustic interaction between moths and plants, but as plants emit various sounds, our findings hint to the existence of more currently unknown insect-plant acoustic interactions.

animal behavior and cognition↗

bioRxiv2024

Early experience affects foraging behavior of wild fruit-bats more than their original behavioral predispositions

There are immense consistent inter-individual differences in animal behavior. While many studies have documented such behavioral differences, often referred to as individual personalities, little research has focused on the underlying causes and on determining whether they are innate or based on individual experience. Moreover, most studies on animal personalities have described consistent differences in behavior under laboratory conditions. We aimed to examine the impact of the early experienced environment on individual animal behavior, and to compare it to that of the individuals original genetic predisposition. Additionally, we explored the correlation between personality traits measured indoors and the animals outdoor behavior. We studied Egyptian fruit bats, in which vast behavioral variability and plasticity have already been demonstrated. We raised bats in a captive colony under either enriched or impoverished environments and assessed their personality under controlled laboratory conditions. We then released the bats into the wild and tracked their foraging using GPS. Bats that had experienced an enriched environment during early life displayed increasing boldness and exploratory behavior when foraging outdoors, demonstrating how early-life experience can affect adult behavior. The individuals original predispositions did not predict their later foraging behavior. Our findings shed new light on the interplay between innate and experienced-based effects on individual behavior. Significance statementAnimals exhibit individual personalities, but how they are shaped is unknown. By employing controlled manipulations on new-born bat pups and GPS-tracking them outdoors as adults, we reveal that the early life conditions bats are exposed to have a significant impact on their foraging behavior as adults. We moreover show that the original individual predispositions of the bats do not predict their behavior. These findings enhance our understanding of the developmental factors that shape animal behavior and emphasize the vital importance of environmental enrichment during early life stages.

animal behavior and cognition↗

bioRxiv2023

Spatial and single-cell transcriptomics illuminate bat immunity and barrier tissue evolution

The Egyptian fruit bat displays tolerance to lethal viruses and unique dietary adaptations, but the molecular basis for this is poorly understood. To this end, we generated detailed maps of bat gut, lung and blood cells using spatial and single-cell transcriptomics. We compared bat with mouse and human cells to reveal divergence in genetic programs associated with environmental interactions and immune responses. Complement system genes are transcriptionally divergent, uniquely expressed in bat lung and gut epithelium, and undergo rapid coding-sequence evolution. Specifically in the tip of the gut villus, bat enterocytes express evolutionarily young genes while lacking expression of genes related to specific nutrient absorption. Profiling immune stimulation of PBMCs revealed a monocyte subset with conserved cross-species interferon expression, suggesting strong constraints to avoid an excessive immune response. Our study thus uncovers conserved and divergent immune pathways in bat tissues, providing a unique resource to study bat immunity and evolution.

genomics↗

bioRxiv2023

Species and habitat specific changes in bird activity in an urban environment during Covid 19 lockdown

Covid-19 lockdowns provided ecologists with a rare opportunity to examine how animals behave when humans are absent. Indeed many, sometimes contradicting, studies reported various effects of lockdowns on animal activity, especially in urban areas and other human-dominated habitats. We explored how Covid-19 lockdowns in Israel have influenced bird activity in an urban environment by using continuous acoustic recordings to monitor three common bird species that differ in their level of adaptation to the urban ecosystem: (1) the hooded crow, an urban exploiter, which depends heavily on anthropogenic resources; (2) the rose-ringed parakeet, an invasive alien species that has adapted to exploit human resources; and (3) the graceful prinia, an urban adapter, which is relatively shy of humans and can be found urban habitats with shrubs and prairies. Acoustic recordings provided continuous monitoring of bird activity without an effect of the observer on the animal. We performed dense sampling of a 1.3 square km area in northern Tel-Aviv by placing 17 recorders for more than a month in different micro-habitats within this region including roads, residential areas and urban parks. We monitored both lockdown and no-lockdown periods. We portray a complex dynamic system where the activity of specific bird species depended on many environmental parameters and decreases or increases in a habitat-dependent manner during lockdown. Specifically, urban exploiter species decreased their activity in most urban habitats during lockdown, while human adapter species increased their activity during lockdown especially in parks where humans were absent. Our results also demonstrate the value of different habitats within urban environments for animal activity, specifically highlighting the importance of urban parks. These species- and habitat-specific changes in activity might explain the contradicting results reported by others who have not performed a habitat specific analysis.

animal behavior and cognition↗

bioRxiv2023

A comparative analysis of the antiviral response in two bat species reveals conserved and divergent innate immune pathways

Bats host a range of viruses that cause severe disease in humans without displaying clinical symptoms to these infections. The mechanisms of bat adaptation to these viruses are a continuous source of interest but remain largely unknown. To understand the landscape of bat antiviral response in a comprehensive and comparative manner, we studied this response in two bat species - the Egyptian fruit bat and the insectivore Kuhls pipistrelle, representing the two major bat subordinal clades. We profiled the transcriptional response to dsRNA - that triggers a rapid innate immune response - in skin fibroblasts from a large cohort of replicates from each bat species, using RNA-sequencing, and compared bat response with responses in primates and rodents. Both bat species upregulate a similar set of genes, many of which are known to be involved in the antiviral response across mammals. However, a subset of these genes is transcriptionally divergent in response between the two bat species. These transcriptionally divergent genes also evolve rapidly in coding sequence across the bat clade and have particular regulatory and functional characteristics, including specific promoter architectures and association with expression programs thought to underlie tolerance and resistance in response to viral infection. In addition, using single-cell transcriptomics, we show that transcriptionally divergent genes display high expression variability between individual cells. A focused analysis of dsRNA-sensing pathways further points to significant differences between bat and human in basal expression of genes important for triggering antiviral responses. Finally, a survey of genes recently lost or duplicated in bats points to a limited set of antiviral genes that have undergone rapid gene loss or gain in bats, with the latter group resulting in paralogs displaying divergence in both coding sequence and expression in bat tissues. Our study reveals a largely conserved regulatory program of genes upregulated in response to viral infection across bats and other mammals, and points to a set of genes that evolved rapidly in bats through multiple evolutionary mechanisms. This divergence can contribute to bat adaptation to viral infection and provides directions to understanding the mechanisms behind it.

evolutionary biology↗

bioRxiv2022

Echolocating bats prefer a high risk-high gain foraging strategy to increase prey profitability

Most bats catch nocturnal prey during active flight guided by echolocation but some species depart from this ancestral behaviour to capture ground prey using passive listening. Here, we explore the costs and benefits of these hunting transitions by combining high-resolution biologging data and DNA metabarcoding to quantify the relative contributions of aerial and ground prey to the total food intake of wild greater mouse-eared bats. We show that these bats use both foraging strategies with similar average nightly captures of 25 small, aerial insects and 30 large, ground-dwelling insects per bat, but with higher capture success in air (78 % in air vs 30 % on ground). However, owing to the 3 to 20 times heavier ground prey, 85 % of the estimated nightly food acquisition comes from ground prey despite the 2.5 times higher failure rates. Further, we find that most bats use the same foraging strategy on a given night suggesting that bats adapt their hunting behaviour to weather and ground conditions. We conclude that prey switching matched to environmental dynamics plays a key role in covering the energy intake even in specialised predators.

animal behavior and cognition↗

bioRxiv2022

A connectomics-based taxonomy of mammals

Mammalian taxonomies are conventionally defined by morphological traits and genetics. How species differ in terms of neural circuits and whether inter-species differences in neural circuit organization conform to these taxonomies is unknown. The main obstacle for the comparison of neural architectures have been differences in network reconstruction techniques, yielding species-specific connectomes that are not directly comparable to one another. Here we comprehensively chart connectome organization across the mammalian phylogenetic spectrum using a common reconstruction protocol. We analyze the mammalian MRI (MaMI) data set, a database that encompasses high-resolution ex vivo structural and diffusion magnetic resonance imaging (MRI) scans of 124 species across 12 taxonomic orders and 5 superorders, collected using a single protocol on a single scanner. We assess similarity between species connectomes using two methods: similarity of Laplacian eigenspectra and similarity of multiscale topological features. We find greater inter-species similarities among species within the same taxonomic order, suggesting the connectome organization recapitulates traditional taxonomies defined by morphology and genetics. While all connectomes retain hallmark global features and relative proportions of connection classes, inter-species variation is driven by local regional connectivity profiles. By encoding connectomes into a common frame of reference, these findings establish a foundation for investigating how neural circuits change over phylogeny, forging a link from genes to circuits to behaviour.

neuroscience↗

bioRxiv2022

Seasonal challenges of tropical bats (Rousettus aegyptiacus) in temperate zones

Egyptian fruit bats (Rousettus aegyptiacus) manage to survive and flourish in a large geographic range despite the variability of natural and anthropogenic conditions in this range. To examine the challenges faced by free-ranging R.aegyptiacus living at the northern edge of their distribution, we performed a retrospective analysis of [~]1500 clinical cases reported by a bat rescue NGO over 25 months, from all over Israel. All cases of injured or stranded bats were evaluated and categorized according to date, place, sex, age, and etiology of the morbidity. The analysis of the data showed an increase in all types of morbidity during the wintertime, with more than twice the number of cases in comparison with the summertime, over two consecutive years. Moreover, we found that the number of abandoned pups peaks during spring till autumn when adult morbidity is minimal. We characterize two prominent types of previously undescribed morbidity in R.aegyptiacus, one in the form of bacterial illness, and the other associated with feet deformation which affects bats in addition to major anthropogenic-related threats related to synanthropic predators. We analyze the reasons driving winter morbidity and conclude that winter weather and specifically low temperature best explains this morbidity. We hypothesize that R.aegyptiacus, a fruit-bat of tropical origin is facing major seasonal difficulties near the northern edge of its distribution, probably limiting its further spread northward.

ecology↗

bioRxiv2020

Sick Bats Stay Home Alone: Social distancing during the acute phase response in Egyptian fruit bats (Rousettus aegyptiacus)

Along with its many advantages, social roosting imposes a major risk of pathogen transmission. How social animals, and especially free-ranging mammals, reduce this risk is poorly documented. We used lipopolysaccharide injection to imitate bacterial sickness in both a captive and a free-ranging colony of an extremely social, long lived mammal - the Egyptian fruit bat. We monitored behavioral and physiological responses using an arsenal of methods, including on-board GPS and acceleration, video, temperature and weight measurements, and blood samples. Sick-like bats exhibited an increased immune response, as well as classical illness symptoms including fever, weight loss, anorexia, and lethargy. Notably, they also isolated themselves from the group by leaving the social cluster and avoiding contact. Free-ranging individuals ceased foraging outdoors for at least two nights. Together, these sickness behaviors demonstrate a strong, integrative immune response which promotes recovery of infected individuals while protecting their group members from transmission of pathogens, and at the same time, reducing spillover events outside the roost.

zoology↗

bioRxiv2019

A spectral jamming avoidance response does not help bats deal with jamming

For decades, researchers have speculated how echolocating bats deal with acoustic interference created by conspecifics when flying in aggregations. It is thus surprising that there has been no attempt to quantify what are the chances of being jammed, or how such jamming would affect a bats hunting. To test this, we developed a computer model, simulating numerous bats foraging in proximity. We used a comprehensive sensorimotor model of a hunting bat, taking into consideration the physics of sound propagation and bats hearing physiology. We analyzed the instantaneous acoustic signals received by each bat, and were able to tease apart the effects of acoustic interference and of direct resource competition. Specifically, we examined the effectiveness of the spectral Jamming Avoidance Response - a shift in signal frequencies - which has been suggested as a solution for the jamming problem. As expected, we found that hunting performance deteriorates when bats forage near conspecific. However, applying a Jamming Avoidance Response did not improve hunting, and our simulations clearly demonstrate the reason: bats have adequate natural signal variability due to their constant adjustment of echolocation signals to the task. The probability to be jammed is thus small and further shifting the frequencies does not mitigate spectral jamming. Our simulations reveal both negative and positive insight: they show how bats can hunt successfully in a group despite potential sensory interference and they suggest that a Jamming Avoidance Response is not useful.

animal behavior and cognition↗

bioRxiv2019

The benefits of insect-swarm hunting in echolocating bats, and its influence on the evolution of bat echolocation signals

Predation on swarms of prey, especially using visual information, has drawn much interest in studies of collective movement. Surprisingly, in the field of biosonar this aspect of prey detection, which is probably very common, has received little to no attention. Here, we combine computer simulations and actual echo measurements to accurately estimate the echo intensity of insect swarms of different size and density. We show that swarm echo intensity increases with 3dB for every doubling of insect number, irrespective of swarm density. Thus swarms will be much easier to detect than single insects. Many of the insects bats eat are so small that they are only detectable by echolocation at very short distances. By focusing on detection of swarms of insects, a bat may increase its operating range and diversify its diet. Interestingly, interference between the sound waves reflected from a swarm of insects can sometimes result in echoes that are much much weaker than echoes from single insects. We show that bats can reduce this problem by increasing the bandwidth of their echolocation calls. Specifically, a bandwidth of 3-8 kHz would guarantee receiving loud echoes from any angle relative to the swarm. Indeed, many bat species, and specifically bats hunting in open spaces, where swarms are abundant, use echolocation signals with a bandwidth of several kHz. Our results might also explain how the first echolocating bats that probably had limited echolocation abilities, could detect insects through swarm hunting.

animal behavior and cognition↗

bioRxiv2018

Flowers respond to pollinator sound within minutes by increasing nectar sugar concentration.

Can plants hear? That is, can they sense airborne sounds and respond to them? Here we show that Oenothera drummondii flowers, exposed to the playback sound of a flying bee or to synthetic sound-signals at similar frequencies, produced sweeter nectar within 3 minutes, potentially increasing the chances of cross pollination. We found that the flowers vibrated mechanically in response to these sounds, suggesting a plausible mechanism where the flower serves as the plants auditory sensory organ. Both the vibration and the nectar response were frequency-specific: the flowers responded to pollinator sounds, but not to higher frequency sound. Our results document for the first time that plants can rapidly respond to pollinator sounds in an ecologically relevant way. Sensitivity of plants to pollinator sound can affect plant-pollinator interactions in a wide range of ways: Plants could allocate their resources more adequately, focusing on the time of pollinator activity; pollinators would then be better rewarded per time unit; flower shape may be selected for its effect on hearing ability, and not only on signaling; and pollinators may evolve to make sounds that the flowers can hear. Finally, our results suggest that plants may be affected by other sounds as well, including antropogenic ones.

ecology↗

bioRxiv2018

The sounds of plants - Plants emit remotely-detectable ultrasounds that can reveal plant stress

Stressed plants show altered phenotypes, including changes in color, smell, and shape. Yet, the possibility that plants emit airborne sounds when stressed - similarly to many animals - has not been investigated. Here we show, to our knowledge for the first time, that stressed plants emit airborne sounds that can be recorded remotely, both in acoustic chambers and in greenhouses. We recorded [~]65 dBSPL ultrasonic sounds 10 cm from tomato and tobacco plants, implying that these sounds could be detected by some organisms from up to several meters away. We developed machine learning models that were capable of distinguishing between plant sounds and general noises, and identifying the condition of the plants - dry, cut, or intact - based solely on the emitted sounds. Our results suggest that animals, humans, and possibly even other plants, could use sounds emitted by a plant to gain information about the plants condition. More investigation on plant bioacoustics in general and on sound emission in plants in particular may open new avenues for understanding plants and their interactions with the environment, and it may also have a significant impact on agriculture.

plant biology↗

bioRxiv2017

Who is the host of the host-associated microbiome? Colony-level dynamics overshadow individual-level characteristics in the fur microbiome of a social mammal, the Egyptian fruit-bat

In the first longitudinal study of bat microbiomes, we find that unlike the pattern described in humans and other mammals, the prominent dynamics in Egyptian fruit bats fur microbiomes are those of change over time at the level of the colony as a whole. Thus, on average, a pair of fur microbiome samples from different individuals in the same colony collected on the same date are more similar to one another than a pair of samples from the same individual collected at different time points. This pattern suggests that the whole colony may be the appropriate biological unit for understanding some of the roles of the host microbiome in social bats ecology and evolution. This pattern of synchronized colony changes over time is also reflected in the profile of volatile compounds in the bats fur, but differs from the more individualized pattern found in the bats gut microbiome.

ecology↗