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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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Behaviour of avian predators to seed bugs (Lygaeoidea): effectiveness of chemical defence
Chalušová, Kateřina ; Exnerová, Alice (advisor) ; Sedláček, Ondřej (referee)
By warning signalling prey advertises its unpalatability to the predators. Typical examples are true bugs (Heteroptera) combining optical and chemical signals. The aim of this study was to find out the effectiveness of chemical defence against wild-caught adults of great tits (Parus major) and blue tits (Cyanistes caeruleus) and towards hand-reared juveniles of great tits. The tested prey were adults and larvae of two invasive species of genus Oxycarenus (Heteroptera: Oxycarenidae) (aposematic O. lavaterae, non-aposematic O. hyalinipennis), adults of Horvathiolus superbus (Heteroptera: Lygaeidae) and crickets (Gryllus assimilis) as a control prey. We were focusing on the influence of seed bugs to the initial reaction, the learning process and to the displays of discomfort behaviour in tits. Reactions affected by the tit species, age and sex were compared in adults. Juveniles were divided into two independent experimental groups, one group was offered adults of genus Oxycarenus, the second was offered sunflower (Helianthus sp.) or Digitalis sp. seed fed adults of H. superbus. The first bug offered did not elicit an initial aversive reaction in tits, but birds reacted aversively to the bugs after having further handling experience. All juveniles, contrary to the adult tits, attacked at least one bug...
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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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