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Experimental studies of Müllerian mimetic complexes
Jůnová, Lenka ; Exnerová, Alice (advisor) ; Hotová Svádová, Kateřina (referee)
Mimicry is one of strategies which provides protection for the prey from predator attack. There are several kinds of mimetic relationships, one of them is Müllerian mimicry, i.e. mutualistic relationship between two unpalatable prey species. If there are more animal species in this relationship, it is called Müllerian mimetic complex. Relationships in mimetic complexes are affected by many factors like defence level and aposematic signals resemblance of particular species, their different frequencies, alternative prey, prey community structure or predator species and their experience level. These factors determine whether the relationship of the species involved is mutualistic or parasitic. They also affect predators behaviour and their learning rate, memory and generalisation between mimetic species. Powered by TCPDF (www.tcpdf.org)
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Reactions of the jumping spider Evarcha arcuata to aposematic true bugs
Raška, Jan ; Exnerová, Alice (advisor) ; Šobotník, Jan (referee)
Jan Raška: Reactions of the jumping spider Evarcha arcuata to aposematic true bugs Abstract: This paper studies the effect of qualities of a prey on predatory behaviour of Evarcha arcuata (Araneae: Salticidae). Naturally coloured aposematic larveae of Pyrrhocoris apterus have been compared to two types of prey: 1) to identically coloured but in defensive secretion different larvae of Scantius aegyptius, and 2) differently coloured larvae of white mutants of P. apterus. The defensive secretion of S. aegyptius has been found less effective in the first interaction with predator than that of P. apterus, however, after several trials the difference of reactions of the spider has not been noticeable. When changed the species of prey, E. arcuata has symmetrically and considerably generalised between the two species. Significant difference has been established in memory test - while P. apterus has been avoided even after one day, S. aegyptius has been attacked as thought the spiders were naive. The learning sequence has been similar in both colour forms of P. apterus; the generalisation of the two colours has been symetrical as well. Both colour forms succeeded in memory test (e.g. spiders have proven difference in comparison with the naive ones), however, white mutants have been successfully attacked...
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Reactions of bird predators on components of repellent secretion of Heteroptera
Malečková, Dana ; Exnerová, Alice (advisor) ; Sedláček, Ondřej (referee)
Aposematic species of true bugs (Heteroptera) have multimodal signalization, which warns potential predators. This signalization consists of optical (coloration), chemical (unpalatable or repugnant substance) and acoustic (stridulation) warning signals. The aim of this thesis was to test whether the selected chemical substances have antipredatory function towards avian predators. Antipredatory function is anticipated in the chemical substances that form the majority in secretion in many taxa of true bugs (aldehydes and tridecane). In experiments with wild-caught great tits (Parus major) and blue tits (Cyanistes caeruleus) we tested if chemical substances and age of birds have influence on the latency related to the first manipulation with the prey. It was found that both species of tits reacted aversively to the mixture of aldehydes (2-decenal, 2-octenal, 2-hexenal) and to the total secretion of metathoracic glands of Graphosoma lineatum, whereas the mixture of the aldehydes with tridecane did not have any effect. The effect of age was not significant. We also tested the influence of immediate experience with striated shieldbug Graphosoma lineatum on naive great tits and their reactions to the prey with olfactoric signal of the shieldbug. Additionally, we investigated whether tested chemicals cause...
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Exploration, neophobia and dietary conservatism in tits (Paridae)
Beranová, Eliška ; Exnerová, Alice (advisor) ; Fučíková, Eva (referee)
Neophobia and exploratory behaviour are two processes applied in great measure in birds' reactions towards novel stimuli. The specific demonstration of these two processes may differ between different species of birds as well as within them. We compared neophobia and exploratory behaviour in two species of tits (Paridae). Adult Great tits (Parus major) and Blue tits (Cyanistes caeruleus) did not differ neither in exploring novel environment and novel object nor in neophobia towards novel object near food. We have found great differences between juveniles of these two species. Juvenile Blue tits were more neophobic towards both novel objects. Age, sex and personality affected some differences within tested species. We tested whether there exist any differences in reactions towards novel food between and within species. We used red painted mealworm (larvae of Tenebrio molitor), house cricket (Acheta domestica) and aposematic bug (Pyrrhocoris apterus) as novel food. Adult wild-caught tits with plentiful experience with various feeds did not differ in reaction towards these types of novel food. In contrast hand-reared juvenile tits differed quite a lot. Juvenile Blue tits were more neophobic than juvenile Great tits towards all three types of novel food. We found dieraty conservatism, phenomenon...
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Effects of multimodal warning siglals of Tritomegas sexmaculatus on reactions of bird predators
Binderová, Jana ; Exnerová, Alice (advisor) ; Kleisner, Karel (referee)
Aposematic animals advertise their defensive mechanisms to potential predators using warning signals. Signalling through more than one sensory pathway is called multimodal warning display. Most experimental studies of aposematism have been focused on the effect of a particular warning signal rather than on importance of multimodal signalling. Focusing on the multimodal signalling of real prey is the best way how to understand its effect in nature. The present study is focused on comparing the effect of multimodal warning display of insect prey with its particular warning signals on two species of bird predators. Multimodal warning signalisation of the burrowing bug, Tritomegas sexmaculatus consists of visual (black and white coloration), chemical (odour, possibly taste) and acoustic (stridulation) signals. We compared reactions of wild-caught great tit (Parus major) and blue tit (Cyanistes caeruleus) to three types of bugs with different warning displays. The non-manipulated bugs displayed multimodally, the brown painted bugs had their warning coloration manipulated and the dealatized bugs couldn't emit acoustic signals. The wild-caught birds of both species avoided all types of bugs. In an experiment with naive hand reared great tits we compared their reactions to non-manipulated and dealatized bugs. Naive...
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