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Motion dazzle and camouflage as distinct anti-predator defenses. BMC Biol 9:81

Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
BMC Biology (Impact Factor: 7.98). 11/2011; 9(1):81. DOI: 10.1186/1741-7007-9-81
Source: PubMed

ABSTRACT Camouflage patterns that hinder detection and/or recognition by antagonists are widely studied in both human and animal contexts. Patterns of contrasting stripes that purportedly degrade an observer's ability to judge the speed and direction of moving prey ('motion dazzle') are, however, rarely investigated. This is despite motion dazzle having been fundamental to the appearance of warships in both world wars and often postulated as the selective agent leading to repeated patterns on many animals (such as zebra and many fish, snake, and invertebrate species). Such patterns often appear conspicuous, suggesting that protection while moving by motion dazzle might impair camouflage when stationary. However, the relationship between motion dazzle and camouflage is unclear because disruptive camouflage relies on high-contrast markings. In this study, we used a computer game with human subjects detecting and capturing either moving or stationary targets with different patterns, in order to provide the first empirical exploration of the interaction of these two protective coloration mechanisms.
Moving targets with stripes were caught significantly less often and missed more often than targets with camouflage patterns. However, when stationary, targets with camouflage markings were captured less often and caused more false detections than those with striped patterns, which were readily detected.
Our study provides the clearest evidence to date that some patterns inhibit the capture of moving targets, but that camouflage and motion dazzle are not complementary strategies. Therefore, the specific coloration that evolves in animals will depend on how the life history and ontogeny of each species influence the trade-off between the costs and benefits of motion dazzle and camouflage.

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    • "dated . There is likely to be a trade - off between animal conspicuousness and movement ; for example , motion dazzle markings are highly conspicuous when prey are stationary but provide protection when moving . In contrast , camouflage provides protection when station - ary , but the same markings may appear conspicuous when the ani - mal moves ( Stevens et al . 2011 ) . This may explain why most prey become immobile or " freeze " when threatened . A study on cuttle - fish found that individuals produced low - contrast patterns when moving , suggesting that the high - contrast patterns in motion dazzle may not impede capture ( Zylinski et al . 2009a ) . However , a target with markings that provide "
    Behavioral Ecology 01/2014; 25(3):468-469. DOI:10.1093/beheco/aru040 · 3.16 Impact Factor
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    • "dated . There is likely to be a trade - off between animal conspicuousness and movement ; for example , motion dazzle markings are highly conspicuous when prey are stationary but provide protection when moving . In contrast , camouflage provides protection when station - ary , but the same markings may appear conspicuous when the ani - mal moves ( Stevens et al . 2011 ) . This may explain why most prey become immobile or " freeze " when threatened . A study on cuttle - fish found that individuals produced low - contrast patterns when moving , suggesting that the high - contrast patterns in motion dazzle may not impede capture ( Zylinski et al . 2009a ) . However , a target with markings that provide "
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    ABSTRACT: In 1909, Abbott Thayer suggested that the study of animal coloration lies in the domain of artists because it deals with optical illusions. He proposed, for example, that prey color patterns may obliterate the animal's outline to make the wearer appear invisible to its preda-tors. Despite a long history of research on the neuropsychology of visual illusions in humans, the question of whether they can occur in other animals has remained largely neglected. In this review, we first examine whether the visual effects generated by an animal's shape, coloration, movement, social environment, or direct manipulation of the environment might distort the receiver's perspective to form an illusion. We also consider how illusions fit into the wider conceptual framework of sensory perception and receiver psychol-ogy, in order to understand the potential significance of these (and other) visual effects in animal communication. Secondly, we con-sider traits that manipulate visual processing tasks to intimidate or mislead the viewer. In the third part of the review, we consider the more extreme cases of sensory manipulation, in which individuals or their traits disrupt, overstimulate, or inactivate receivers' sensory systems. Although illusions present just one form of sensory manipulation, we suggest that they are likely to be more common than previously suspected. Furthermore, we expect that research in this area of sensory processing will provide significant insights into the cognitive psychology of animal communication.
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    • "Computer-based experiments tested the effect of distractive marking size, location, and number on both detection times and on the speed of predator learning (decrease in detection times across trials). Provided humans are not used to test the coloration of real species that have nonhuman predators, experiments conducted with human subjects offer a useful route to test general principles of antipredator coloration (e.g., motion dazzle; Stevens et al. 2008d, 2011; Scott-Samuel et al. 2011). In particular, work has conrmed the generality of results from eld studies by using human subjects searching for similar camouaged stimuli on computer screens (e.g., Fraser et al. 2007; Cuthill and Székely 2009). "
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