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Final Report Summary - MOTDAZZ (Dazzle markings and movement as an anti-predator strategy)

Predation exerts strong selective pressures that have far-reaching effects on prey life history traits. As a result, animals that are vulnerable to predation have evolved a suite of anti-predator defences, including colouration or markings that exploit the sensory systems of their predators. To date, the majority of studies on anti-predator markings have focussed on stationary prey items and have not investigated whether different markings can affect the likelihood of capture when prey are in motion. Given that objects are easiest to detect when in motion, theory predicts that selection should also influence markings that provide protection when the animal is moving. This project is testing the efficacy of patterns or markings that may affect the capture rate of moving prey targets.
The presence of high contrast patterns on some animals has been suggested to serve an anti- predator function by altering the predator’s perception of the movement, speed or trajectory of the target, termed ‘motion dazzle’. High contrast patterns such as black and white stripes may be effective anti- predator markings as they interfere with motion detection mechanisms in the eye, making it difficult for the viewer to accurately perceive the direction or speed of the movement.
We established a collaboration with FoAM Kernow to develop a citizen science project that tested the visual effects of motion dazzle. We created an online game where humans acted as predators trying to catch patterned targets as they moved across a computer screen (see These targets then evolved based on how easily they were captured, with easily caught targets being removed from the population and the remaining targets producing a new generation of patterns. This simulates pattern evolution in response to predation. These patterns then continued to evolve as players attempted to capture each new set of patterns, so that patterns evolved to become harder to catch, and reflect the most effective patterns in terms of difficulty of capture. The online game has evolved 15 populations at three different speeds of movement, and analysis of these results in currently underway.
We also publicized the online game through online media with an article in The Conversation that had over 4000 views (see, Twitter, and at the Behaviour 2015 Conference in Australia. The game also has a webpage that goes into more detail about the theory behind motion dazzle (see The game has also been modified to allow for more rapid evolution so that it can be used as a teaching tool by lecturers and teachers at graduate and school level to educate about animal patterns, predation and evolution.
From these data we will determine what patterns are most successful at avoiding predation when other selection pressures are removed. This citizen science project has formed a valuable outreach opportunity and has generated large amounts of data for the project. The findings are of interest to the general public but are also relevant to the military. Motion dazzle patterns were painted on ships in the First World War but their effectiveness was ambiguous so use of the patterns was discontinued. There is also evidence that motion dazzle patterns can provide military vehicles with protection from artillery due to effects on speed perception. The patterns generated by Dazzle Bug are effective at manipulating speed perception and can therefore be of use in situations were manipulation of speed perception is beneficial.
The second major objective of this project was to investigate the visual effects of motion dazzle using non-human animals as predators. We aimed to use Eurasian jays and scrub jays as predators, but these experiments could not be concluded as husbandry issues with the populations of birds used meant that numbers tested were too low to achieve the statistical power required. We established a collaboration with Professor Johanna Mappes and Dr Bibiana Rojas at Jyväskylä University in Finland, where Prof Mappes has facilities for testing wild-caught great tits on motion dazzle patterns. We have an ongoing project presenting great tits with moving paper targets that bear putative model patterns. We anticipate that this collaboration will be fruitful and long-lasting, and will allow us to test various anti-predator patterns on wild birds.

During this fellowship the researcher has carried out numerous outreach activities. She authored four articles for The Conversation, an online news site where content is generated by academics. These articles have been read over 208,000 times and have also featured in The Guardian and the Oxford University Press blog. She has also given seminars at the University of Exeter (UK), the University of Liverpool (UK) and Jyväskylä University (Finland). She has presented at two international conferences, the International Society for Behavioral Ecology (USA) and Behaviour 2015 (Australia), and attended two Association for the Study of Animal Behaviour conferences (UK).

The researcher also authored a review on visual illusions (including motion dazzle) in non-human animals. It was published as a forum article in Behavioural Ecology and so included responses from leading academics in the field as well as a another publication she authored in response. The review has been cited 19 times and was received coverage via the Conversation article in The Guardian and the Daily Mail.

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