Explore the vast range of titles available.

Epilepsy is a common neurological disorder giving rise to both recurrent and spontaneous seizures as well as additional neurological comorbidities. In approximately 30% of patients, seizures are not ameliorated by existing anti-seizure drugs. To bridge this treatment gap, the larval zebrafish has emerged as a powerful model for high-throughput drug-screening, based on changes in swimming behavior during seizures. However, such screening has low specificity and thus requires subsequent, low-throughput validation of drug candidates. We found that behavioral escape responses to startling stimuli are strongly reduced for a few hours after seizures, suggesting this behavioral change could serve as a useful assay to identify drugs ameliorating seizures with higher specificity. Moreover, we found that the extent of behavior change and the rate of recovery are dependent on convulsant concentration which determines seizure strength. Finally, we demonstrated that an anti-epileptic drug, Valproic acid, reduced swimming behavior during seizures as well as mitigated the reduction in post-seizure escape behaviors. Nevertheless, it also reduced escape behaviors in the absence of seizures. These data argue that monitoring escape behavior after drug treatment and after seizures provides an improved high throughput assay to identify new anti-epileptic drugs as well as reveal non-specific effects of drugs on neural circuit function, which may predict side-effects in humans.

Animals living close to human settlements more often experience disturbance, but also reduced predation risk. Because an escape response is costly, behavioural adjustments of animals in terms of increased tolerance of humans occurs and is often reported in the literature. However, most such studies have been conducted in and around long-existing cities in Europe and North America, on well-established animal populations. Here, we investigate the degree of tolerance of human disturbance across 132 bird species occurring in disturbed (small farms) and undisturbed (intact wetlands and grasslands) areas in Pantanal, Mato Grosso (Brazil), a region with only a very recent history of human-induced disturbance. We found a clear across-species trend toward higher tolerance of human disturbance in birds near farms when compared with birds in wild areas. Such a flexible and perhaps also rapid emergence of tolerance when facing small-scale and very recent human disturbance presumably involves learning and might be attributed to behavioural plasticity. The ability of birds to modify their degree of tolerance of human disturbance may play a key role in the facilitation of wildlife–human coexistence.

In many animal species, collective behaviours can be explained by a simple set of interaction rules. It is an intriguing question whether this generality at the level of mechanism also translates into generality at the level of function. Assuming that collective behaviour provides antipredator benefits for the partaking individuals, we ask whether the same collective behaviour provides protection against different predators in general. We investigated this question in sulphur-adapted fishes in their natural habitats in Mexico. Here, fish schools are frequently attacked by many different bird species and fish respond with synchronized and often repeated collective diving behaviour (escape waves). We found all bird species to wait longer until they attacked as they encountered more waves, both before they launched their first attack (pre-attack) and between subsequent attacks (post-attack). Post-attack, all bird species triggered similarly high numbers of waves while species differed in the number and the interval between the waves they triggered pre-attack. Through simulated bird arrivals, we confirmed that birds in the pre-attack context could be perceived as less threatening or completely overlooked, depending on their size, colouration and contrast to the background. We argue that the generality in the fish’s collective response as well as the similarity in effect on the different birds’ hunting behaviour might be explained by waves targeting a weakness in the visual processing ability common to different predators.

Fish are elusive prey with a short-latency escape behavior--the C-start--initiated to either the left or right by a \"race\" between 2 giant Mauthner neurons in the fish brainstem. Water disturbances usually excite the ipsilateral neuron, which massively excites contralateral motor neurons, resulting in a rapid turn away from striking predators. Here, it is reported that tentacled snakes (Erpeton tentaculatus) exploit this normally adaptive circuitry by feinting with their body, triggering the Mauthner cell that is furthest from their head milliseconds before a ballistic strike is initiated. As a result, fish that were oriented parallel to the long axis of the snake's head most often turned toward the approaching jaws, sometimes swimming directly into the snake's mouth. When strikes were instead directed at fish oriented at a right angle to the snake's head, snakes anticipated future fish behavior by striking to where fish would later be if they escaped from the snake's body feint, which fish usually did. The results provide an example of a rare predator taking advantage of a prey's normally adaptive escape circuitry and suggest that the snake's sensory-motor system is adapted to predict future behavior.

In lizards, males are predicted to sprint faster and run for longer than females by virtue of higher testosterone levels and differences in morphology. Consequently, escape behaviour is also predicted to be associated with sex and locomotor performance, yet these links have rarely been explored. Here, we tested whether escape behaviour is associated with locomotor performance in the toad-headed agama, Phrynocephalus vlangalii, and whether it is sex-dependent. This species is also characterized by elaborate tail displays, which we examined as a potential pursuit-deterrent signal. Tail waves were performed by a very small proportion (2/58, 3 %) of individuals during predatory trials, suggesting that tail signalling functions exclusively in a social context. To understand the relationships between sex, escape behaviour and performance, we first measured escape behaviour (flight initiation distance, flight distance—measured differently compared to previous studies of lizard escape behaviour, and refuge use) in the field before measuring maximal sprint speed and endurance on the same individuals in the laboratory. Flight initiation distance did not differ between the sexes and was unrelated to performance capacity (maximal endurance and sprint speed) but was positively related to body size with larger individuals fleeing earlier. Males fled farther than females, but flight distance was also unrelated to either endurance or sprint speed. Interestingly, faster females were less likely to enter a refuge than slower females, whereas sprint speed and the probability of taking refuge were unrelated for males. Our results suggest that when males and females are not obviously sexually dimorphic, they are more likely to overlap in escape tactics.

Collisions between birds and aircraft are a global problem. We identified different behavioural parameters affecting the probability of escape from a potential collision with an approaching aircraft, which is a function of the probability that the animal initiates an escape response (probability of reaction) and the probability of having enough time to escape (probability of sufficient time). Lights of high chromatic contrast tuned to the avian eye have been proposed as a solution to mitigate collisions. We approached Canada geese with a drone to estimate how aircraft lighting and changes in altitude, mimicking the flight phase where most strikes occur, affect parameters associated with the probability of escape. Onboard lights increased parameters associated with the probability of reaction at farther distances by promoting longer detection distances, which enabled the animal to initiate each stage of its escape response sooner leading to longer flight-initiation distances irrespective of altitude changes. Additionally, onboard lights increased parameters associated with the probability of sufficient time where longer detection distances allowed animals to escape away from (as opposed to towards) the approaching drone. Our findings have implications for the development of light technology to deter birds away from approaching vehicles, and other anthropogenic structures (such as wind turbines and solar facilities).

We tested the hypothesis that magnetic alignment, a tendency to align the body axis with a certain angle to the field lines of the geomagnetic field, provides direction indicator (the so-called nonsense orientation) also in mammals. We measured alignment of free-ranging (grazing or standing) roe deer and the compass direction of their escape trajectories as well as the direction from the threat and to the next shelter. Roe deer were significantly nonrandomly aligned along the north-south axis when grazing. In 188 provocations performed in open flat habitats, deer also tended to escape along this axis and avoided to escape westwards or eastwards. Thus, in many provocations (those from east or west), animals fled at wide angles, either northwards or southwards and not straight away from the threat, a strategy that would maximize the distance between the animal and the danger. Since all the factors which might influence direction of escape (sun position, wind direction, direction to the shelter, straight direction from danger) were randomly distributed in time and space, they constitute just statistical noise which does not add. The only common denominator of all data sets was the magnetic field. We conclude that the north-south alignment expresses the readiness to escape along this axis and might help to synchronize the movement and cohesion of the group and also supports mental mapping of space.

Flight initiation distance (FID) is a metric often used to study an individual's perceptions of risk when facing a predatory threat. Longer FID indicates lower risk‐taking, while shorter FID identifies bolder individuals who tolerate greater risk. Until now, no studies have tested the potential effect of the observer's sex on the escape behaviour of wild birds. Given observed differences in how laboratory animals may respond to the sex of humans interacting with them, the lack of reports in the field is surprising. In five European countries, we tested whether urban birds perceived the risk posed by approaching female versus male observers differently, using FID as a response variable. First, we matched the female and male observers according to their height and clothing. Then, we fitted Bayesian regression models, controlling for the phylogenetic relatedness of bird species, to test for the effect of human observer sex after controlling for a variety of other important factors known to explain variation in FID (starting distance, flock size, sex of the target bird, land use characteristics and vegetation cover). We found that male birds were more risk‐tolerant than females and – unexpectedly—birds in general escaped sooner when approached by women than by men. The escape difference associated with the observer's sex ( 1 m longer when approached by women than by men) was consistent in populations across all five examined European countries. We discussed various hypotheses to explain birds' escape responses related to the observer's sex; however, further research is necessary to fully understand this phenomenon. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog.

Most studies examining escape behaviour have considered single approaches and single fleeing responses; few have considered how organisms’ response is influenced by persistent pursuit. We explored fleeing behaviour of two grasshopper species to test whether they modified escape behaviour when approached repeatedly. Schistocerca alutacea did not increase flight initiation distance (FID) upon repeated approach but fled farther. Psinidia fenestralis increased its FID on the second approach but decreased its flight distance over successive escapes. Both species showed a bimodal pattern of flight direction, either flying directly away or flying perpendicular to the direction of the observer’s approach. Neither species showed a significant pattern of flight direction or change in flight direction with successive escapes. Most (88 %) P. fenestralis initially landed on sand, but after repeated approaches an increasing proportion landed in grass and hid. Both species therefore changed escape behaviour with persistent pursuit but used different tactics, suiting their flight ability or camouflage, and optimised habitat use. Three grasshopper species have now been examined for responses to repeated approach by predators and all show different tactics supporting escape decision theory. Our results emphasise the variety of escape responses across species and how the dynamic nature of escape responses vary according to an animal’s situation. Rather than single optimum escape options, each grasshopper species shows a range of responses, which vary with risk from persistent predators. Although grasshoppers provide an excellent model, it would be profitable to examine responses of a range of species according to levels of predation risk.

I describe a White-banded Swallow (Atticora fasciata) diving under water to avoid predation by a Bat Falcon (Falco rufigularis) in Madre de Dios River, Peru. On 3 September 2006 I observed a White-banded Swallow plunge-diving under water for a distance of 30 cm (6 times) with 1 m flights close to the water surface in between (5 times) before reaching a safe spot on the river bank. Received 16 October 2017. Accepted 18 August 2018.