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Role of aldehydes in multimodal aposematic signallig of true bugs
Bednářová, Hana ; Exnerová, Alice (advisor) ; Sedláček, Ondřej (referee)
1 Abstract: Multimodal signaling is quite common in nature. Even if we focus only on signaling among prey and its predator, we can still find many examples of communication combining more than one modality (vision, hearing, smell, taste). This thesis is about multimodal warning visual and olfactory signaling between true bugs (Heteroptera) and their avian predators. Aldehydes are an important compound of repellent secretion of most true bug species. They are considered to have defence effects against predators. In our experiments, we tested the effect of aldehydes mixture on behaviour of predators - naive hand-reared and experienced wild-caught adult great tits (Parus major) - towards several kinds of prey - aposematic true bugs Pyrrhocoris apterus, nonaposematic true bugs Pyrrhocoris tibialis and red painted mealworms (Tenebrio molitor larvae). We were focusing on the effect of aldehydes on initial reaction, learning process and predator's memory. Aldehydes elicited innate wariness in naive hand- reared great tits towards aposematic P. apterus, but not towards P. tibialis. Therefore it seems possible, that aldehydes act as a signal of unpalatability for naive predators, but only in multimodal combination with visual warning signal. Similar effect of aldehydes was not found in experiments with wild-caught...
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Role of aldehydes in multimodal aposematic signallig of true bugs
Bednářová, Hana ; Exnerová, Alice (advisor) ; Sedláček, Ondřej (referee)
1 Abstract: Multimodal signaling is quite common in nature. Even if we focus only on signaling among prey and its predator, we can still find many examples of communication combining more than one modality (vision, hearing, smell, taste). This thesis is about multimodal warning visual and olfactory signaling between true bugs (Heteroptera) and their avian predators. Aldehydes are an important compound of repellent secretion of most true bug species. They are considered to have defence effects against predators. In our experiments, we tested the effect of aldehydes mixture on behaviour of predators - naive hand-reared and experienced wild-caught adult great tits (Parus major) - towards several kinds of prey - aposematic true bugs Pyrrhocoris apterus, nonaposematic true bugs Pyrrhocoris tibialis and red painted mealworms (Tenebrio molitor larvae). We were focusing on the effect of aldehydes on initial reaction, learning process and predator's memory. Aldehydes elicited innate wariness in naive hand- reared great tits towards aposematic P. apterus, but not towards P. tibialis. Therefore it seems possible, that aldehydes act as a signal of unpalatability for naive predators, but only in multimodal combination with visual warning signal. Similar effect of aldehydes was not found in experiments with wild-caught...
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Experimental research of specificity of fear of snake: coral snake pattern
Průšová, Lucie ; Frynta, Daniel (advisor) ; Veselý, Petr (referee)
Due to shared coevolutionary history of snakes and primates with snakes acting as their main predators, snakes elicit fear in most of the primates, humans included. Humans are able to notice a stimulus that elicits fear, e.g., a snake, much faster. Such ability might have surely positively affected their survival in the past. In the nature, aposematic coloration acts as a warning of a dangerous prey to its predators not to devour it. The highly poisonous American coral snakes have this coloration pattern. The harmless king snakes of the Central and North Americas gain an anti-predatory advantage by becoming the coral snakes 'Batesian mimics, copying their bright pattern. Such pattern elicits an innate fear reaction in various species of wild birds who avoid a mere contact with patterned plastic dummies. The question arises whether other taxa, including primates and humans, generally recognize such pattern as dangerous. The aim of this study was to find whether humans fear coral snakes, although they have not long coevolutionary history with them. Further it was analyze, which visual factors of the snakes affect this fear reaction (i.e., a warning coloration, pattern or shape of snake). The atractiveness of these snakes was tested. Another question was whether humans are able to intuitively recognize...
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