National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Evolution of prey-catching behaviour in poikilothermic vertebrates and its relationship with predator's visual perception
Košinárová, Lucie ; Frýdlová, Petra (advisor) ; Robovská, Pavla (referee)
Both the topics of prey-catching mechanism and visual perception are closely connected, affecting each other in many complex situations. The main subjects of this thesis were amphibians and reptiles and the many effects that impact their hunting abilities. We studied their hunting patterns in a few species of frogs and the leopard gecko (Eublepharis macularius) in an arena. We did not find any universal hunting pattern for neither of those groups, moreover even the quantity of individual sequences differed among them. However, hunting in nature is often engaged in habitats that are far from the flat calm arena. Often the animals have to adapt to different conditions, for example an unsteady surface underneath them. In such conditions they need to compensate for the passive movement with their heads and eyes to stabilize the image on their retina. The ability to compensate while hunting in frogs is affecting their behaviour and the success rate of their prey-catching. Another aspect that is influencing frog's hunting efficiency are their protrusible tongues that are commonly divided into three categories: mechanical, inertial and hydrostatic. The last goal of this thesis was looking for the evolution of this trait in frog's phylogenesis and their different effects on hunting movements.
Hunting mechanism and visual perception of prey in amphibians
Košinárová, Lucie ; Frýdlová, Petra (advisor) ; Černý, Rudolf (referee)
Visual perception holds the dominant position among other senses in amphibians. It provides vital information about any potential prey or predators in the surrounding area. Any information, gained through optical sensors, is then directly evaluated in brain, activating different behavioral reactions: prey catching or predator avoidance behaviour. Decision is based on individual parameters of stimuli. In case of identifying a prey stimulus an innate behavior pattern is activated. There are many prey catching strategies in amphibians. Their selecting may vary due to many aspects including food preferences, mechanical constraints or a phylogenetic position of the species. Habitat may also have an influence over hunting strategy or even morphological characters of species, mostly regarding their oral system. Tongue plays an important role in almost every prey catching movement in terrestrial and also in some aquatic amphibians. There are different types of tongue elongation in amphibians that are divided into several categories, which can affect the hunting strategy for each species. Apart from creating a summary about visual perception and hunting mechanisms, this thesis includes a mapping of different types of tongue elongation on a phylogenetic tree of amphibians. The main goal of this task is to find a...

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