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Reactions of predators towards species of red-and-black mimetic complex
Kotlíková, Lucie ; Exnerová, Alice (advisor) ; Baňař, Petr (referee)
The red-black mimetic complex in the Western Palaearctic region includes a large number of arthropod species. These species differ in the degree of their mimetic resemblance, as well as in defensive mechanisms and their effectiveness against various predators. This study is based on two experiments. The first experiment was carried out with adult great tits (Parus major) and artificial prey (photographs). The birds were divided into two experimental groups and were trained to discriminate between palatable and unpalatable prey. One group was trained with higher diversity in the coloration of unpalatable prey (ten species of subfamily Lygaeinae), while the other was trained with low diversity in the coloration of palatable prey (ten individuals of the same species, Lygaeus equestris). After ten learning blocks, two generalization blocks followed, in which both groups received the same prey that was completely different from the prey during learning phase. The rate of learning was not significantly different between the two groups. However, more effective generalization was observed in the group trained with higher prey diversity. However, this trend was only observed in the first generalization block. On the second day, both groups achieved similar generalization success. The second experiment was...
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Mechanisms and effectiveness of antipredatory defences within red-and-black mimetic complex
Kotlíková, Lucie ; Exnerová, Alice (advisor) ; Baňař, Petr (referee)
Strikingly coloured species can form mimetic complexes. One of them is an extensive black-and-red mimetic complex in the Palearctic region. It consists of representatives across arthropod taxa with different levels of defense and investment in it. To describe individual mimetic relationships in this complex, it is necessary to know the effectiveness of these defense mechanisms against predators. Reactions of individual predators vary considerably. Differences in reactions primarily depend on the ability to perceive some components of defense, using sensory and cognitive abilities. Mechanisms and effectiveness of antipredatory defence are the subject of numerous studies, but there is still a lack of description of some mechanisms among many representatives forming this mimetic complex. For this reason, further studies are needed to allow the derivation of mimetic relationships prevailing in this mimetic complex in the future. Keywords: mimicry, aposematism, antipredatory defense, colouration, mimetic complex
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Category discrimination in avian predators: formation of natural categories of unpalatable prey
Zíková, Markéta ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
Ability to categorize objects to classes and react to members of one class similarly is important for animals, for example to facilitate discrimination between palatable and unpalatable prey. Objects are typically categorized according to their common features. Birds mainly use visual perception and so their prey also signals its unpalatability visually, through aposematic coloration. We studied the ability of great tits (Parus major) to categorize prey into classes of palatable and unpalatable according to its appearance. Birds were divided to three experimental groups, each tested with different categories of prey. First group was trained to discriminate between aposematic species of true bugs (Heteroptera) and non-aposematic species from other insect taxa. Second group was trained to discriminate non-aposematic species of true bugs and species of other insect taxa and the third in discrimination of pseudocategories, consisting of randomly assigned stimuli from the first experimental group. Tested birds were wild-caught adults and naïve, hand-reared juveniles. Juveniles were tested only in first two experimental groups. All birds were first trained in discrimination between the two categories and then tested in a generalization test with new stimuli. Both adults and juveniles learned to...
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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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