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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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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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Signs of the Origin and Evolution of Eusociality in Hymenoptera on Genomic Level
Fraňková, Tereza ; Straka, Jakub (advisor) ; Musilová, Zuzana (referee)
Eusociality has evolved independently many times in social Hymenoptera and some of them are now at the brink of eusociality. Eusociality is a complicated set of genomic, ecological and behavioural traits closely interacting with each other. Recent studies presented many interesting outcomes which explain at least partially the possible connections to eusociality on the genomic level. However, the true origin and evolution of eusociality is yet to be refined. Because eusociality is such a dominant quality in the lives of eusocial Hymenoptera, it is important to clarify what causes eusociality to arrise. This thesis summarises the most prominent findings in the field of genomics and reviews not only the outcomes but also the issues of this problematics. The thesis deals with the classification of eusociality, brief introduction to the species lifestyles, which are of great importance for understanding the main part. The main part focuses on the concrete genomic data elucidating possible signs of the evolution of eusociality recognised so far. Key words: eusociality, genomics, evolution, Hymenoptera, Insecta
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Population genetics and speciation in Stylops (Strepsiptera)
Kodejš, Karel ; Straka, Jakub (advisor) ; Černá, Kateřina (referee)
This thesis is focused to population genetics of selected species of genus Stylops in Europe. Within this genus, five species was analysed by usage of two approaches - microsatellite analysis in Stylops ater and analysis of mitochondrial DNA in all five species. Mitochondrial gene for cytochome c oxidase (1st subunit) was used. For microsatellite analysis was performed bayesian clustering analysis and ABC approach (Aproximate Bayesian Computation). Mitochondrial markers were processed by making haplotype networks and demography analysis by computing Bayesian skyline plots. For Stylops ater, surprisingly low lewel of population subdivision was detected, yet with clearly differentiated population clusters from Scandinavia and baltic coast of Europe, which may imply period of isolation of these populations or relativelly recent population expansion and genetic differentiation due to lower population sizes. Next, hypotesis of possible temporal segregation of subpopulations of Stylops nevinsoni based on different aktivity period of their host species groups, was supported. In other three species, population subdivision was observed to be related either due to host specialisation (Stylops mellitae) or geographic consequences (S.nassonowi, S.spreta). Interesting finding is also detection of population...
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Visualization of insect morphological structures using x-ray microtomography and other modern 3D techniques
Rosová, Kateřina ; Prokop, Jakub (advisor) ; Janšta, Petr (referee)
In my bachelor thesis I describe techniques currently used for 3D visualization of morphological structures of insects. Since X-ray microtomography is currently the most attractive option for visualizing internal insect structures, more space is dedicated to its description, but the work includes more innovative techniques. Traditional techniques used in the past decades are not neglected, since they do not lose their importance in the competition of new methods. In the first part the individual methods are presented in terms of their simplified functional mechanisms and the basic steps of creation of 3D reconstructions are described. Techniques are further compared in the text in terms of their usability on different types and sizes of samples, according to the desired final resolution of the visualization, the time required to complete the observation and final visualization and in terms of invasiveness of the techniques. The last chapter summarizes the possibilities of using these innovative methods in entomology based on available studies. Keywords: Insecta, morphology, 3D visualization, SEM, CLSM, MRI, Micro-CT
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The articulation of insect wings
Křečková, Adéla ; Prokop, Jakub (advisor) ; Král, David (referee)
The origin of wings is one of the most important innovation in insect evolution which opened new niches due to unique flight abilities. Movement of the wing is provided by the specific wing base structures consisted of the articular sclerites and the flight muscles. In general there are three main types of basal articulation in insects. Neopteran articulation represents presumably the ancetral type from which the others are derived. These are found in two palaeopteran orders Ephemeroptera and Odonata. Palaeoptera differs from Neoptera by incapability of the wing flexion over the abdomen. This incapability is caused by their specific articulation of the wings to the thorax. Various arrangements of wing sclerites among insect groups have significance in respect of phylogeny and thus represent number of important morphological characters. These are therefore used in higher systematics of extant groups as well as scarcely in their extinct fossil relatives. In the present thesis I introduce the review of literature sources concerning the main types of the wing articulation, their homologies and their significance in respect of higher insect phylogeny.
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Quaternary insects and their significance for zoogeography, paleoclimatology and paleoecology
Moudrý, Jakub ; Prokop, Jakub (advisor) ; Říhová, Dagmar (referee)
The present thesis is a review of available published data on Quaternary insects. Research focused on Quaternary insects has been so far overlooked by the Czech scientists, even though there is potential to provide additional data for complex reconstruction of Quaternary deposits. Insect faunas allow to trace the dynamic development of areas across continents and serve for example as proof of migration routes. It is especially true for the Pleistocene, well known for prominent climatic oscillations. Thus, the insect species served as climatic indicators allowing estimations of average temperatures by application of the MCR method. Finally, these faunal changes reflect dynamic development of palaeoenvironments. The fact that the subfossil taxa correspond to the recent species allows broader reconstruction of the Quaternary deposits.
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Phylogeny and evolution of habitat preferences of the subfamilies Rygmodinae and Sphaeridiinae (Coleoptera: Hydrophilidae)
Sýkora, Vít ; Fikáček, Martin (advisor) ; Zrzavý, Jan (referee)
Subfamilies Rygmodinae and Sphaeridiinae together form approximately one third of the extant diversity within the family Hydrophilidae (Coleoptera: Polyphaga). Members of both these subfamilies inhabit wide spectrum of aquatic and terrestrial environments including specialized habitats such as phytotelmata, carrion or termite nests. So far, habitat shifts within these subfamilies have been only tested with a limited amount of taxa at the family level. Using a broader sampling and Bayesian and maximum likelihood methods, genus-level molecular phylogenetic analysis and divergence dating were performed. The dataset included 96 taxa, representing all major clades (genus groups) in both subfamilies, sequenced for two mitochondrial and two nuclear genes. A single shift from the aquatic to terrestrial environment in the Middle Jurassic was suggested, thus revealing both subfamilies and all tribes as ancestrally inhabiting decaying plant material and leaf litter. Secondary returns to aquatic habitats were suggested for two lineages of the Rygmodinae and several lineages belonging to tribes Coelostomatini and Megasternini. A single shift to flowers was revealed in the subfamily Rygmodinae. Similarly, single independent shifts to the inquiline lifestyle in tribes Omicrini and Megasternini were revealed. In...
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Origin and evolution of insect wings
Patlevič, Matyáš ; Prokop, Jakub (advisor) ; Pecháček, Pavel (referee)
Insecta is the most diversified animal group, which comprises more than a half of eukaryotic species. Its massive adaptive radiation is most frequently attributed to an origin of insect's wings and flapping flight. Due to lack of transitional forms in fossil record it is impossible to study directly these procedures but only in a theoretical approach only. In this thesis the origin of insect wings is considered in two ways - in evolutionary way, when the points of interest are selection pressures and evolutionary advantages for insects with proto-wings, and a morphological way, when objects of study are structures that preceded wings and developmental modules allowing this event. The present thesis contains review of relevant published hypothesis dealing with evolutionary and morphological origin of insect wings.
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Palaeodictyoptera: morphology of immature wings from the Upper Carboniferous of Poland
Tippeltová, Zuzana
Insect wings are very specific and unique structures in animal kingdom. Wing morphology is a result of long-standing complicated evolutionary process and until recently the way how the wings have evolved is not completely clarified. The flight ability is one of the most important event in insect history because it allows them to exploit new habitats, escape from predators or find the sexual partner. Here we present the newly discovered material consisting of Palaeodictyoptera immature wings from the Upper Carboniferous (Westphalian A) of Poland. This order became extinct in the end of Permian, however during the Late Paleozoic was remarkably diversified. Until recently, number of adult palaeodictyopterans have been described, however the immature stages are relatively unknown due to lack of suitable fossils. Immature wings present in this thesis have undoubtedly palaeodictyopterous affinities with atribution within superfamilies Breyeroidea and Homoiopteroidea. However, their familial assignment into Breyeriidae (morphotype A) and Homiopteridae (morphotype B) based on fore wing venation characters is not definite because of wing venation limits in early ontogenetic stages. The aim of the present work is a complex description of 14 new palaeodictyopteriids immature wings, and to point out certain...
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