Biology subjects

Newport, C.

Publications and source records attributed to Newport, C..

9 recordsLinked to original sources

bioRxiv2026

Heatwaves and turbidity influxes have interacting and lasting effects on the foraging behaviour of three-spined stickleback Gasterosteus aculeatus

Freshwater ecosystems support a disproportionately high share of fish species and biodiversity yet are among the most threatened ecosystems globally and are increasingly being exposed to multiple, co-occurring environmental stressors. In addition, predicting the combined impacts of environmental stressors remains a major challenge, particularly when stressors differ in how quickly they arise and how long their effects persist. Understanding how these stressors interact across time is critical for predicting their ecological consequences. Here, we examine how warming and turbidity, two widespread and intensifying stressors, interact to influence predator-prey dynamics in the three-spined stickleback (\textit{Gasterosteus aculeatus}). Using a fully factorial experiment, fish were exposed to ambient, warmed, turbid, or combined conditions for short (one week) or prolonged (six weeks) periods, before feeding rates were quantified across prey densities using a novel stochastic Bayesian model. We found that foraging behaviour was shaped primarily by prior exposure rather than the immediate experimental conditions. Short-term exposure to both stressors increased feeding rates, whereas prolonged warming reduced them. In contrast, turbidity continued to increase feeding rates over both time periods and, when combined with warming, offset the negative effects of extended heat exposure. Changes in feeding performance at the individual level may propagate through food webs, potentially triggering trophic cascades that reduce biodiversity. Given the exceptional biodiversity of freshwater systems, such dynamics are of particular concern. We also found that behavioural changes persisted even after stressors were removed, indicating that exposure history can have lasting effects. These findings suggest that short-term experiments, such as the functional response, may actually be measuring subject experiential history rather than responses to specific experimental conditions.

animal behavior and cognition↗

bioRxiv2026

Big-team science reveals that patterns of inhibitory control variation in teleost fishes differ from those in mammals and birds

Understanding the evolution of cognition is fundamental to understanding the origins and nature of our own cognitive abilities, with cross-species comparisons providing a cornerstone of this endeavor. Yet, comparative cognition so far has largely focused on endothermic vertebrates, particularly mammals and birds, while ectotherms--representing a substantial proportion of vertebrate diversity--remain relatively understudied. Moreover, variation in experimental methods makes existing data difficult to compare across species. Big-team science offers a way to overcome these limitations by enabling standardized cognitive testing across broad taxonomic scales. Here, we apply this approach to fishes, using inhibitory control as a proof of concept for standardized comparative testing in 444 individuals across 22 teleost species spanning 19 genera. We demonstrate that standardized cognitive testing across such diversity is feasible, while also revealing substantial heterogeneity in the sample. Performance varied markedly among species, but, strikingly, showed only a weak phylogenetic signal, contrasting with patterns previously reported in mammals and birds. In addition, we detected great within-species variation, including differences across research groups, suggesting that performance may reflect not only species-level evolutionary history but also ontogenetic experience and the capacity to adjust decision rules to local conditions. Together, our findings highlight the importance of both evolutionary and environmental sources of cognitive variation and demonstrate that extending standardized comparative approaches beyond traditionally studied endotherms can reveal a more dynamic and complex picture of cognitive evolution across the vertebrate lineage.

animal behavior and cognition↗

bioRxiv2026

BEEhaviourLab: A high-throughput platform for sublethal stressor screening in insects

Behavioural responses often provide the earliest detectable signs of physiological stress yet quantifying them at scale remains challenging. Acoustic behaviours such as buzzing are central to insect locomotion and communication but are rarely measured systematically, and their potential as sensitive indicators of environmental stress remains largely unexplored. Here, we test whether changes in insect acoustic behaviour can reveal sublethal effects of pesticide exposure. Using a newly developed automated behavioural platform (BEEhaviourLab), we recorded synchronised video and audio from insects, enabling simultaneous, high-throughput quantification of locomotor activity and buzzing behaviour across multiple individuals and species without the need for tagging. We applied this system to characterise the effects of the veterinary antiparasitic moxidectin on the bumble bee Bombus terrestris. Acute contact exposure produced dose-dependent reductions in locomotion and buzzing behaviour at concentrations below lethal thresholds. Acoustic measures detected behavioural disruption with sensitivity comparable to video-based activity metrics, demonstrating that buzzing behaviour provides a sensitive and previously unused indicator of neurotoxic stress. More broadly, scalable multimodal behavioural phenotyping enables subtle behavioural disruption to be detected across large experiments, opening new opportunities to incorporate acoustic endpoints into studies of animal behaviour, environmental stress, and ecological risk assessment.

animal behavior and cognition↗

bioRxiv2024

A sensory approach to turbidity: How sources and levels shape aquatic light environments and fish visual ecology

Turbidity is a ubiquitous source of sensory pollution that is likely to impact the appearance of the visual stimuli that animals rely on for survival and reproduction. Understanding how different turbidity sources impact the appearance of the ambient light environment is the foundational first step towards predicting whether and how animals will cope with the global increases in the severity and frequency of high turbidity events caused by anthropogenic disturbance. Here, we measured how four common turbidity sources (algae, bentonite, calcium carbonate, and kaolin), and variable turbidity levels, changed the appearance of the ambient light environment. We measured total number of photons (luminance), hue, chroma, and image contrast, and we evaluated the effect of each turbidity source and level on settling rate, pH, and KH. Both turbidity source and turbidity level impacted the appearance of the ambient light environment. With increasing turbidity level, calcium carbonate and kaolin increased luminance while algae decreased luminance, bentonite caused the greatest change in hue, and algae caused the greatest change in chroma. This demonstrates that the impacts of different turbidity sources on the ambient light environment are not uniform, giving a potential explanation for the discrepancies between studies on the effects of turbidity on fish behaviour. Consideration of the effect of specific turbidity sources on ambient light is crucial for the design of experiments that seek to investigate how changes in turbidity impact the perception of important visual information, which underpins the survival and reproductive success of aquatic organisms around the world. Summary StatementDifferent turbidity sources and levels uniquely affect aquatic light environments and fish visual perception, emphasizing the need for these factors when interpreting fish behaviour and the ecological consequences of turbidity.

animal behavior and cognition↗

bioRxiv2023

A robust and flexible deep-learning workflow for animal tracking

Developments in automated animal behavioural analysis software are increasing the efficiency of data collection and improving the standardization of behavioural measurements. There are now several open-source tools for tracking laboratory animals, but often these are only accurate under limited conditions (e.g. uniform lighting and background, uncluttered scenes, unobstructed focal animal). Tracking fish presents a particular challenge for these tools because movement at the waters surface introduces significant noise. Partial occlusion of the focal animal can also be troublesome, particularly when tracking the whole organism. But identifying the position of an animal is only part of the task - analysing the movement of the animal relative to their environment and experimental context is often what provides information about their behaviour. Therefore, the automated detection of physical objects and boundaries would also be beneficial, but this feature is not commonly incorporated into existing tracking software. Here we describe a video processing method that uses a range of computer vision algorithms (e.g. object detector and tracker, optical flow, parallel plane homology) and computational geometry techniques (e.g. Voronoi tessellation) to analyse the movement behaviour of fish in response to experimental stimuli. A behavioural experiment, which involved tracking a fishs trajectory through a field of obstacles, motivated our development of a set of tools that: (1) measure an animals trajectory, (2) record obstacle position, and (3) detect when the fish passed through virtual gates between adjacent obstacles and/or the aquarium wall. We have introduced a novel Detect+Track approach that significantly enhances the accuracy and robustness of animal tracking, overcoming some of the limitations of existing tools and providing a more reliable solution for complex experimental conditions. Our workflow is divided into several discrete steps, and provides a set of modular software building blocks that can be adapted to analyse other experimental designs. A detailed tutorial is provided, together with all the data and code required to reproduce our results.

animal behavior and cognition↗

bioRxiv2022

The influence of visual pollution on navigation mechanisms in the damselfish (Chrysiptera cyanea)

Here, we investigate whether visual pollution has an effect on navigation in coral reef damselfish (Chrysiptera cyanea). Turbidity had no significant influence on the individual fishs preference between egocentric and visual cues in a simple navigation task, with all individuals exhibiting a striking egocentric preference across all turbidity levels under testing. However, an alteration of cue preference may have occurred on a fine scale. Turbidity had profound effects on fish movement and decision-making behaviour, which has substantial implications for the behaviour of fishes on the ecological scale of a coral reef.

animal behavior and cognition↗

bioRxiv2022

Decision-making strategies of a coral reef fish given changing visual signal reliability

Making informed decisions is fundamental to intelligent life and is crucial to survival. The problem many organisms face, is how to make optimal decisions in the face of incomplete, unreliable, or conflicting information. In many aquatic environments, fish use visual information to guide key behaviours, but the environment itself can alter or mask the very signals they rely on. Here, we asked how a highly visual species, Rhinecanthus aculeatus, responds to a learned discrimination task as signal reliability decreases, and whether probabilistic information gained during previous experience can be incorporated into their decision strategy. Fish were first trained to select a target (dark grey circle) from three distractors (light grey circles). In the first experiment, the target was more likely to appear in one of four possible stimulus positions. In the second experiment, the target appeared in all positions equally. In a series of trials, the difference in brightness between the target and distractors was reduced until all four stimuli were identical. We found that target selection accuracy decreased with decreasing target and distractor disparity. However, in Experiment 1 where the target was more likely to be in one position, fish increasingly selected stimuli in the biased position as target selection accuracy decreased, but not in Experiment 2. These results demonstrate 1) that fish learned more than a simple select/avoid rule based on stimulus brightness, but also integrated information (stimulus position) that could be considered ancillary to the primary task. 2) Fish can learn probability distributions and apply this knowledge as uncertainty increases, ultimately increasing the overall frequency of correct choices. Our results reveal that probabilistic decision rules can be used by fish when visual information is unreliable, indicating a possible mechanism for decision making given the inherent noise in incoming sensory information.

animal behavior and cognition↗

bioRxiv2022

Distance estimation in the Goldfish (Carassius auratus)

Neurophysiological advances have given us exciting insights into the systems responsible for spatial mapping in mammals. However, we are still lacking information on the evolution of these systems and whether the underlying mechanisms identified are universal across phyla, or specific to the species studied. Here we address these questions by exploring whether a species that is evolutionarily distant from mammals can perform a task central to mammalian spatial mapping - distance estimation. We developed a behavioural paradigm allowing us to test whether goldfish (Carassius auratus) can estimate distance and explored the behavioural mechanisms that underpin this ability. Fish were trained to swim a set distance within a narrow tank covered with striped pattern. After changing the background pattern, we found that goldfish use the spatial frequency of their visual environment to estimate distance; doubling the spatial frequency of optic flow pattern resulted in a large overestimation of the swimming distance. These results provide robust evidence that goldfish can accurately estimate distance, and show that they use optic flow to do so. These results provide a compelling basis to utilise goldfish as a model system to interrogate the evolution of the mechanisms that underpin spatial cognition, from brain to behaviour.

animal behavior and cognition↗

bioRxiv2019

The structure and function of the sucker systems of hill stream loaches

Hill stream loaches (family Balitoridae and Gastromyzontidae) are thumb-sized fish that effortlessly exploit environments where flow rates are so high that potential competitors would be washed away. To cope with these extreme flow rates hill stream loaches have evolved adaptations to stick to the bottom, equivalent to the downforce generating wings and skirts of F1 racing cars, and scale architecture reminiscent of the drag-reducing riblets of Mako sharks. Hill stream loaches exhibit far more diverse flow-modifying morphological features than fast pelagic predators, suggesting as yet unknown drag reducing systems remain to be discovered. Here we describe the skeletal structure of Sewellia lineolata and Gastromyzon punctulatus and contrast that with other fish that face similar hydrodynamic challenges. We identify a major structural variation within Balitoridae pelvic sucker attachment positions which may explain fundamental constraints on the parallel development of different genera and which has not been described before. We also use high speed video capture, CT scans and Frustrated Total Internal Reflection to image and measure the sucker system in live operation and describe how it functions on a familiar activity for hill stream loaches (climbing waterfalls). We show how they can drag 3 to 4 times their own bodyweight up a vertical glass waterfall. Adaptations to high flow rates are the inspiration for this study, because there are many engineering applications where the ability to deal with high flow rates are important - either by reducing drag, or by generating the forces needed to hold an animal in place.

zoology↗