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Factors affecting prey detectability for visual predators
Machalková, Kateřina ; Exnerová, Alice (advisor) ; Javůrková, Veronika (referee)
The cryptic coloration is one of the main ways to protect prey before the visually directing predators. Most animals use two basic strategies of crypsis, background-matching and disruptive coloration. The aim of this thesis was to summarize and evaluate knowledge about different strategies of cryptic coloration. The study was mainly focused on the confrontation between insect prey and predator bird. Experimental studies are comparing the effectiveness of cryptic coloration of prey by a combination of background-matching and disruptive coloration with prey characteristics (inner pattern contrast, background contrast, shape and pattern distribution, symmetry) or background parameters (background complexity, multiple backgrounds, the distance between the prey and the predator) that affect detectability. The results of the study conclude that disruptive coloration pattern in cryptic prey has better effects than the strategy of background-matching. Prey characteristics can affect detectability, but the results of individual studies are not conclusive. Even the background parameters results were unambiguous, the highest efficiency for prey detection time was a combination of disruptive coloration and the background complexity. The issue of camouflage is so complex that the majority of studies do not have...
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Crypsis on the principles of disruptive coloration
Kopčiková, Kristýna ; Kreisinger, Jakub (advisor) ; Pecháček, Pavel (referee)
The crypsis gives the oportunity to an animal to become inconspicuous in its natural environment to avoid being detected by potential observer (Cott, 1940, Edmunds 1974 Merilaita 2003). But crypsis isn't unambiguous term, there are few ways to achieve being cryptic and disruptive coloration and background-matching are one of them. The aim of this thesis is to summarize empirical evidence for the inmportace, the function and the expansion of disruptive coloration in nature. This research also constitutes a fundamental experiments testing the principles of disruptive patterns. It turns out that this coloration could bring for the bearer some selective advantages, but the experiments are too uniform and they have important methodological failures. Results of them are unclear so scientists have no consistent conclusions. The issue of disruptive coloration is very complicated and still poorly explored. There is need to invest a lot of more labor and study to be certain whether or how disruptive coloration works in nature. Powered by TCPDF (www.tcpdf.org)
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