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Population Genetics of Parasites and Their Arthropod Hosts
Bezányiová, Kateřina ; Straka, Jakub (advisor) ; Votýpka, Jan (referee)
Arthropoda are currently the largest metazoan phylum. Given that organisms with parasitic lifestyle are thought to comprise the majority of existing species, it's easy to imagine an immense diversity of parasites interacts with arthropods. However, in comparison to organisms parasitising vertebrates, parasites of arthropods are direly understudied despite their abundance, importance, and potential usefulness. Amongst other things, parasites can be used as tools allowing the inference of information on host life history, ecology, and past events the host species have experienced. Population genetic structure of parasites and other symbionts may reflect these traits and events due to their close relationship with the host. Even though parasites comprise a diverse assemblage of taxa, it's possible to identify convergent patterns in their biology. Models predicting congruent population genetic co- structuring can be thus based on a few traits such as host specificity, life cycle complexity or parasite and/or host dispersal. In some cases, the parasite may provide better resolution of population structure than the host itself, serving as a proxy that may be used to direct conservation programmes of both the host and parasite, as has already been done with parasites of vertebrates. This thesis summarises known...
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Gigantism of Paleozoic insects and other arthropods
Pecharová, Martina ; Prokop, Jakub (advisor) ; Knor, Stanislav (referee)
Gigantism of insects and other arthropods was rather common in Late Paleozoic. Hypothesis of the oxygen limitation is one the probable explanations caused the phenomenon. Carboniferous insect gigantism was probably directly caused by the higher level of atmospheric oxygen due to direct effectiveness on the tracheal system. Therefore the possibility to grow to large sizes is clearly dependent on the amount of available oxygen. Another fact supporting the hypothesis is the extinction or the change of the giant insect forms at the end of the Permian, when the level of atmospheric oxygen suddenly decreased. This thesis also describes the ecological relationships of the Late Paleozoic arthropods, which is clearly connected to the evolution of giant forms. Gigantism during this period was thus developed by the interplay of several factors related to the global elements cycles. Another part covers major groups and representatives of Palaeozoic gigantic insects and other arthropods. The final part is devoted to describing the physiological experiments related to this topic.
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Adaptation of terrestrial arthropods to the cave environment
Rothová, Helena ; Šťáhlavský, František (advisor) ; Růžička, Vlastimil (referee)
Every living things on our planet is adapted to the environmen it inhabitst, and a number of factors affect its overall appearance and behaviour. This is especially true for organisms living in environments with extreme conditions, where it has to adapt to be able to use the often limited resources. One of these environments are subterranean spaces lacking any light and having a limited supply of nutrients. This bachelor thesis presents a brief overview of the basic types of underground spaces and the way nutrients get into them, which are important factors that determine the presence of different groups of organisms. This thesis also summarizes the terminology used in relation to this type of environment. However, the main aim of this paper is to describe morphological, physiological, as well asbehavioral adaptations to subterranean life of terrestrial representatives from particula groups of the tribe Arthropoda (Arachnida, Myriapoda, Crustacea, Hexapoda). From the presented list of specific adaptations in those groups it follows that all main evolutionary lines show similar types of adaptations, such as depigmentation, reduction or complete loss of vision, prolongation of body appendices, multiplication of sensory setae and enlargement of the body, as well as adaptations that help organisms to...
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Reactions of spider and insect predators to aposematic prey
Koláčná, Klára ; Exnerová, Alice (advisor) ; Sentenská, Lenka (referee)
Aposematic prey advertises its unprofitability to predators by means of warning signals, which can be visual, chemical, acoustic or combined with each other as multimodal signals. Most experimental studies dealing with responses of predators to aposematic prey focus on vertebrates, especially birds. This thesis focuses on the most frequently tested groups of terrestrial arthropod predators - spiders, dragonflies, and mantises - supplemented by less tested insect predators. Most of the tested arthropod predators are able to learn to avoid noxious aposematic prey based on either visual, olfactory or acoustic signals depending on their perception. Some can remember this aversion for several days. Only in case of jumping spiders, ability to generalise previous experience with a particular prey to similar prey has been confirmed. Prey chemical defenses most often consist of cardenolides or aldehydes, which proved to be aversive for tested arthropod predators.
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Functions of myrmecomorphy in the arthropods and its occurrence and potential functions in true bugs
Hrebiková, Tereza ; Exnerová, Alice (advisor) ; Pipek, Pavel (referee)
Myrmecomorphy (ant mimicry) is structural and chromatic (sometimes also chemical and behavioural) resemblance to ants. Ant-mimicking species can be found in many arthropod taxa particularly in spiders and true bugs. Myrmecomorphy may serve several functions, protecting the mimics either from the ants themselves or from predators. Mechanisms of ant mimicry have been studied mostly in spiders and some insect taxa (e.g. beetles). In true bugs (Hemiptera: Heteroptera), ant mimicry exists in many species belonging to several families, and it is present in both larvae and adults. Notwithstanding its frequent occurrence, the literature about ant mimicry in true bugs is limited only to several incomplete lists of myrmecomorphic species, hypotheses on mimicry functions, and a few experimental studies. This thesis aims to review (1) experimental studies focused on function of ant mimicry in spiders and insects and (2) occurrence, form and potential function of ant mimicry in true bugs (Heteroptera). Key words: Myrmecomorphy, function, Arthropoda, spiders, insects, Heteroptera
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Gigantism of Paleozoic insects and other arthropods
Pecharová, Martina ; Prokop, Jakub (advisor) ; Knor, Stanislav (referee)
Gigantism of insects and other arthropods was rather common in Late Paleozoic. Hypothesis of the oxygen limitation is one the probable explanations caused the phenomenon. Carboniferous insect gigantism was probably directly caused by the higher level of atmospheric oxygen due to direct effectiveness on the tracheal system. Therefore the possibility to grow to large sizes is clearly dependent on the amount of available oxygen. Another fact supporting the hypothesis is the extinction or the change of the giant insect forms at the end of the Permian, when the level of atmospheric oxygen suddenly decreased. This thesis also describes the ecological relationships of the Late Paleozoic arthropods, which is clearly connected to the evolution of giant forms. Gigantism during this period was thus developed by the interplay of several factors related to the global elements cycles. Another part covers major groups and representatives of Palaeozoic gigantic insects and other arthropods. The final part is devoted to describing the physiological experiments related to this topic.
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