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Mimicry in hoverflies
Daňková, Klára ; Hadrava, Jiří (advisor) ; Raška, Jan (referee)
Batesian mimicry, the imitation of harmful species manifested by harmless ones, could bring a lower risk of predation to the mimetic species. Therefore, it occurs in many different taxa. Hoverflies (Diptera: Syrphidae) could stand for one of the most various mimics. This worldwide-distributed family is known for taking shape of many Aculeata species using plenty of different adaptation connected with colouration, morphology and even behaviour. The aim of this work is to review the diversity of mimicry in Syrphidae, highlight the main selection pressures and to put forward a potential field of future research. Hoverflies are being studied for the last two hundred years. However, just several study approaches are dominating the field. In order to open a new chapter of their research, I bring a wider synthesis of knowledge related to the ecological and evolutionary context of this phenomenon.
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Mimicry of hoverflies (Diptera: Syrphidae) in the context of selection pressures from predators, thermoregulation and sexual selection
Daňková, Klára ; Janšta, Petr (advisor) ; Pekár, Stanislav (referee)
Thermoregulation plays an important role in organisms' lives during foraging, escaping from predators, sexual selection or overwintering. Moreover, pressure on efficient thermoregulation could affect species on an evolutionary level and was recently hypothesized to maintain imperfect mimicry in hoverflies (Diptera, Syrphidae). We set these two aims: 1) to study relationships between thermoregulation, mimicry accuracy and resembled model, 2) to closely study effect of developmental temperature in an intermediately accurate honeybee mimic, Eristalis tenax. In the first part of the project, we examined temperature excess of 566 specimens in 47 species of hoverflies in the field. We did not find significant effect of mimicry accuracy on temperature excess in our data. However, we found a strong sexual dimorphism. Females had lower temperature excess, which was very resilient to internal and external factors, whereas males had higher temperature excess, influenced by activity at time of capture (flying > sitting) and resembled model (bumblebee-mimics > honeybee- mimics > wasp-mimics > solitary bee-mimics). We suggest, that males are pushed to higher temperature excess by sexual selection within lekking. In the second part of the project, we reared E. tenax in three different temperatures in laboratory...
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Mimicry in hoverflies
Daňková, Klára ; Hadrava, Jiří (advisor) ; Raška, Jan (referee)
Batesian mimicry, the imitation of harmful species manifested by harmless ones, could bring a lower risk of predation to the mimetic species. Therefore, it occurs in many different taxa. Hoverflies (Diptera: Syrphidae) could stand for one of the most various mimics. This worldwide-distributed family is known for taking shape of many Aculeata species using plenty of different adaptation connected with colouration, morphology and even behaviour. The aim of this work is to review the diversity of mimicry in Syrphidae, highlight the main selection pressures and to put forward a potential field of future research. Hoverflies are being studied for the last two hundred years. However, just several study approaches are dominating the field. In order to open a new chapter of their research, I bring a wider synthesis of knowledge related to the ecological and evolutionary context of this phenomenon.
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The Mimicry of Coral Snakes and King Snakes and the Approaches of Adolf Portmann
Čtrnáctová, Lenka ; Figura, Roman (advisor) ; Brejcha, Jindřich (referee)
The problem of the supposedly mimetic relationship between some species of king snakes and coral snakes is rather scattered in literature and opinions on it vary greatly. In this work, I focus on summarizing and generalizing the existing pieces of knowledge about the colouration of these snakes and its consequences for evolutionary biology - neodarwinistic and especially portmannistic. In other words, natural selection does not solve all the questions and in this case in particular, it is obvious that mimesis interests not only biologists, but also mathematicians, chemists, physicists and philosophers. All of these are trying to find the answer to whether mimesis in these snakes is actually occurring and what would be the purpose of such colouration if it is not. Adolf Portmann is very clear on this subject: organisms show their inner properties on the outside as a means to self-present. The specific appearance is not determined and it does not have to have any adaptive value at all.
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Devil Guardian: The Theme of Identity in Mexican Novel on the break of the Millenium.
Alon, Andrea ; Vydrová, Hedvika (advisor) ; Housková, Anna (referee) ; Riebová, Markéta (referee)
The theme of the dissertation submitted is the novel Devil Guardian, whose author is a Mexican writer Xavier Velasco. This dissertation is the very first theoretical work in the Czech environment, devoted to the above-mentioned piece of literature published in 2004. In a sense, Devil Guardian represents a characteristic Mexican novel of the early 21st century, combining tradition and novelty in a surprising and original manner. A significant feature of the contemporary Mexican literature is a departure from the theme of Mexicanity, generally from a programmatic indulging in so-called national literature. Velasco's novel is an exemplary, however, not only piece of literature proving that the literary break-up with Mexico is neither an exclusive nor a dominant attribute of the contemporary Mexican fiction. In Devil Guardian Velasco focuses his mind on the theme of personal and national identity, which he treats in a considerably nontraditional manner, giving an ironical turn to speak to a hypermodern girl moving in the globalized world. The dissertation is divided into six parts. The first part "Originality Rooted in Tradition" refers to Devil Guardian ensuing the tradition of Mexican novel and innovating it. The second part "Xavier Velasco" briefly introduces the author's life and work. The issues...
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Methodology of application of film language
Sýs, Alan ; Horný, Stanislav (advisor) ; Seko, Martin (referee)
The Bachelor Thesis is focused on the expressive means of film and the methodology of their application. It portrays, how the application of the methods may influence the final meaning of the artwork, respectively suggests, how to achieve the authors intent in the most effective way, through the coscious utilization of film language. In order to achieve the objects of this paper were chosen the most significant expressive elements, which are described in detail and subsequently demonstrated on concrete examples of the bachelor movie Marek is smiling.
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