Biology subjects

Herbert-Read, J.

Publications and source records attributed to Herbert-Read, J..

3 recordsLinked to original sources

bioRxiv2022

Evolution of schooling propensity in the guppy drives changes in anti-predator behavior that are linked to neuroanatomy

One of the most spectacular displays of social behavior is the synchronized movements that many animal groups perform to travel, forage and escape from predators. However, elucidating the neural mechanisms underlying the evolution of collective behaviors, as well as their fitness effects, remains challenging. Here, we study anti-predator behavior in guppies experimentally selected for divergence in polarization, an important behavioral aspect of coordinated movement. We find that groups from artificially selected lines remain more polarized than control groups in the presence of a threat. Neuroanatomical measurements of polarization-selected individuals indicated changes in brain regions previously suggested to be important regulators of perception, fear and attention, and motor response. Additional visual acuity and temporal resolution tests performed in polarization-selected and control individuals indicate that observed differences in anti-predator and schooling behavior should not be attributable to changes in visual perception, but rather are more likely the result of the more efficient relay of sensory input in the brain of polarization-selected fish. Our findings highlight that brain morphology may play a fundamental role in the evolution of coordinated movement and anti-predator behavior.

evolutionary biology↗

bioRxiv2021

The measure of spatial position within groups that best predicts predation risk depends on group movement

Both empirical and theoretical studies show that an individuals spatial position within a group can impact the risk of being targeted by predators. Spatial positions can be quantified in numerous ways, but there are no direct comparisons of different spatial measures in predicting the risk of being targeted by real predators. Here we assess these spatial measures in groups of stationary and moving virtual prey being attacked by three-spined sticklebacks (Gasterosteus aculeatus). In stationary groups, the limited domain of danger best predicted the likelihood of attack. In moving groups, the number of near neighbours was the best predictor but only over a limited range of distances within which other prey were counted. Otherwise, measures of proximity to the groups edge outperformed measures of local crowding in moving groups. There was no evidence that predators preferentially attacked the front or back of the moving groups. Domains of danger without any limit, as originally used in the selfish herd model, were also a poor predictor of risk. These findings reveal that the collective properties of prey can influence how spatial position affects predation risk, via effects on predators targeting, hence selection may act differently on prey positioning behaviour depending on group movement.

animal behavior and cognition↗

bioRxiv2020

Achromatic body markings as a widespread visual mechanism across group living animals

Grouping is a widespread form of predator defense, with individuals in groups often performing evasive collective movements in response to predators attacks. Individuals in these groups use behavioral rules to coordinate their movements, with visual cues about neighbors positions and orientations informing movement decisions. Although the exact visual cues individuals use to coordinate their movements with neighbors have not yet been decoded, some studies have suggested that stripes, lines or other body patterns may act as conspicuous conveyors of movement information that could promote coordinated group movement, or promote dazzle camouflage, thereby confusing predators. We used phylogenetic logistic regressions to test whether the contrasting achromatic stripes present in four different taxa vulnerable to predation, including species within two orders of birds (Anseriformes and Charadriiformes), a suborder of Artiodactyla (the ruminants) and several orders of marine fish (predominantly Perciformes) were associated with group living. Contrasting patterns were significantly more prevalent in social species, and tended to be absent in solitary species or species less vulnerable to predation. We suggest that stripes taking the form of light-colored lines on dark backgrounds, or vice versa, provide a widespread mechanism across taxa that serves either to inform conspecifics of neighbors directional movement, or to confuse predators, when moving in groups. Detection and processing of patterns and of motion in the visual channel is essentially colourblind. That diverse animal taxa with widely different vision systems (including di-, tri- and tetrachromats) appear to have converged on a similar use of achromatic patterns is therefore expected given signal-detection theory. This hypothesis would explain the convergent evolution of conspicuous achromatic patterns as an antipredator mechanism in numerous vertebrate species.

evolutionary biology↗