Turbidity, the scattering of light by suspended particles in water, constrains the ability of animals to gather information from their surroundings. Although turbidity varies naturally, turbidity is increasing globally in fresh and coastal waters due to intensified agriculture, deforestation, quarrying and urbanisation, combined with the increasing frequency and intensity of extreme weather events driven by climate change. This growing sensory smog has a wide range of ecological effects, particularly on predator-prey interactions including how predators search their environment for prey, their probability of detecting prey, and how socially hunting predators interact. These effects, however, depend on the sensory systems that predators rely on (Ehlman et al. 2020). While vision is an important sensory modality for many fish species, the lateral line (a system of mechanoreceptors that detect changes in water pressure) is also used by many fish for detecting and capturing prey, and during shoaling interactions. However, we know very little about how the senses of predators determine their susceptibility to environmental change.
Project Aims and Methods
The project aims to link the sensory capabilities of predatory fish to how their response to prey, and to one another during hunting, is affected by water turbidity. Can we predict which species, or individuals within species, will experience reduced hunting efficiency in turbid water from variation in their visual and lateral line traits? Does the effect of turbidity depend on whether prey are conspicuous or cryptic? Is the effect of turbidity on shoaling also mediated by sensory traits, and what impact does this have on predation by social predators?
We welcome the student being involved in setting the specific research questions within this topic, as well as the design of the empirical and modelling studies. A key approach available to be used is a method recently developed by the main supervisor of presenting prey to fish individually and in small shoals under controlled laboratory conditions that allows the precise moment of the predator’s response to the prey to be determined (MacGregor et al. 2020). The behaviour of individual fish in these tests will be coupled with data on their visual and lateral line systems, quantified after the predation trials. The empirical findings will then be incorporated into models of collective behaviour to explore these trends in much larger systems that can simulate a population of thousands of social or non-social predators searching and detecting prey over large spatial scales.
Candidate requirements
The project will suit a candidate interested in the interface between animal behaviour and environmental change. The project will involve behavioural experiments, processing of animal samples in the laboratory, and extensive programming to analyse data and simulate collective behaviour. We welcome and encourage student applications from under-represented groups. We value a diverse research environment.
Project partners
The project is a collaboration between the universities of Bristol and Exeter, two internationally-recognised centres for research in behavioural and sensory biology that is one of the largest groupings of scientists working in these fields anywhere in the world. Cuthill and Hauert have further extensive networks via two of Bristol’s major interdisciplinary research themes of vision (the Bristol Vision Institute) and robotics (Bristol Robotics Laboratory), as well as links to industry, giving the student an even wider scope to network and collaborate. Equipment and methods needed for the project are already in use by the supervisors, and behavioural trials will take place in the School of Biological Sciences’ £2M state-of-the-art aquarium facility.
Training
The supervisory team is assembled to be able to provide training in the wide range of methodological approaches that the project integrates. This will include behavioural experimentation, quantifying animal movement from video using automated tracking software, quantifying the visual and lateral line sensory systems of fish, advanced statistical techniques to analyse data, and modelling predatory and collective behaviour. The student will attend at least one international animal behaviour conference (e.g. ISBE). To mitigate any potential risks from Covid-related travel disruptions, the experimental work can take place entirely in the laboratory facilities at the University of Bristol, although both Ioannou and Genner have extensive experience working in tropical freshwater systems where turbidity shows huge variation over time and/or space. Field-based studies could thus be incorporated into the PhD if feasible.
Making an application
When applying for the GW4+DTP Projects in the School of Biological Sciences please choose 'Biological Sciences (PhD)' from the Programme Choice drop down menu (see Prospectus for other Schools offering projects under this DTP). You will need to make a separate application for each project.
It is important that you follow the detailed instructions provided in the How to apply link and read the Admissions Statement in the Prospectus to apply for one of these projects.
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