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Evolution of Host Specialisation, Phylogeography and Taxonomic Revision of Xenidae (Strepsiptera)
Benda, Daniel
Twisted-winged parasites (Strepsiptera: Xenidae) are an excellent group for studying the specialisation of parasites on hosts. Their parasitic lifestyle led to the evolution of numerous morphological, behavioural, physiological, and reproductive adaptations. Moreover, many complex adaptive traits of Strepsiptera have no parallel in other organisms. In contrast, little attention has been paid to the study of strepsipteran molecular phylogeny, phylogeography, species delimitation, and their implications for taxonomic classification. Using the methods of molecular phylogeny, we created the first dated phylogenetic study of the family Xenidae. By investigating historical biogeography and ancestral host groups, we indicate that multiple lineages were exchanged between the New World and the Old World + Australia until Antarctica became completely frozen over. During the late Paleogene and Neogene periods, several lineages spread from the Afrotropics to other Old World regions and Australia. The original hosts of Xenidae were most likely social wasps, and the subsequent host switch from social to solitary wasps was secondary and probably occurred only once. The parallel host switch from solitary wasps to digger wasps (Sphecidae) occurred independently in the New and Old World. The biogeography and...
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Evolution of Host Specialisation, Phylogeography and Taxonomic Revision of Xenidae (Strepsitera)
Benda, Daniel ; Straka, Jakub (advisor) ; Malenovský, Igor (referee) ; Cook, Jerry L. (referee)
Twisted-winged parasites (Strepsiptera: Xenidae) are an excellent group for studying the specialisation of parasites on hosts. Their parasitic lifestyle led to the evolution of numerous morphological, behavioural, physiological, and reproductive adaptations. Moreover, many complex adaptive traits of Strepsiptera have no parallel in other organisms. In contrast, little attention has been paid to the study of strepsipteran molecular phylogeny, phylogeography, species delimitation, and their implications for taxonomic classification. Using the methods of molecular phylogeny, we created the first dated phylogenetic study of the family Xenidae. By investigating historical biogeography and ancestral host groups, we indicate that multiple lineages were exchanged between the New World and the Old World + Australia until Antarctica became completely frozen over. During the late Paleogene and Neogene periods, several lineages spread from the Afrotropics to other Old World regions and Australia. The original hosts of Xenidae were most likely social wasps, and the subsequent host switch from social to solitary wasps was secondary and probably occurred only once. The parallel host switch from solitary wasps to digger wasps (Sphecidae) occurred independently in the New and Old World. The biogeography and...
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Holocene Climatic Optimum in the Iranian region: geoarchaeological and climatological study in relation to human settlement
MARŠÁK, Daniel
This thesis collects previous knowledge and information about palaeoenvironmental and archaeological situation in the area of Iran primarily from the Holocene Climatic Optimum period, sometimes called as Altithermal. Holocene Climatic Optimum is characterized by high temperatures and high intensity of atmospheric precipitation and it lasts from 9000 cal. BP to 5000-6000 cal. BP. The research work aims to map the process of the human settlement as a result of warm Climate Changes. This will be accomplished by making a contribution of Geoarchaeological and Palaeoclimatic proxies which are going to introduce and reconstruct forming conditions for the human settlement. Significant element of the thesis is identification of the Hunter-Gatherer societies and interception theirs agricultural transition. The most important area for this transition is Southwestern part of the Islamic Republic of Iran (Khuzestan Province, Lorestan Province, Ilam Province). The Zagros Mountains which "include" these Provinces will be subjected to the depth analysis.
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Holocene history of Arctic lakes
Roman, Matěj ; Nývlt, Daniel (advisor) ; Kavan, Jan (referee)
Holocene history of Arctic lakes Abstract Palaeolimnology in the Arctic has achieved a considerable progress in the last decades. The Arctic has changed markedly since the Last Glacial and glacier retreats caused formation of a great number of diverse lake types. Lakes of glacial origin, thermokarst lakes, fluvial lakes and lakes on raised beaches occur most often here. Palaeolimnological methods applied to the high latitude areas are used for the study of the history of individual lakes. Methods of correlation of sedimentary cores and basic interpretation of proxy records such as magnetic susceptibility, diatom biostratigraphy and content of carbon and sulphur were applied on sediments of Garmaksla Lake, Svalbard Archipelago. Climatic and ecological shifts including the Little Ice Age termination and recent warming were registered in proxy values. Keywords: lakes, palaeolimnology, palaeoclimatology, environmental changes, Holocene, Arctic
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Holocene history of Arctic lakes
Roman, Matěj ; Nývlt, Daniel (advisor) ; Kavan, Jan (referee)
Holocene history of Arctic lakes Abstract Palaeolimnology in the Arctic has achieved a considerable progress in the last decades. The Arctic has changed markedly since the Last Glacial and glacier retreats caused formation of a great number of diverse lake types. Lakes of glacial origin, thermokarst lakes, fluvial lakes and lakes on raised beaches occur most often here. Palaeolimnological methods applied to the high latitude areas are used for the study of the history of individual lakes. Methods of correlation of sedimentary cores and basic interpretation of proxy records such as magnetic susceptibility, diatom biostratigraphy and content of carbon and sulphur were applied on sediments of Garmaksla Lake, Svalbard Archipelago. Climatic and ecological shifts including the Little Ice Age termination and recent warming were registered in proxy values. Keywords: lakes, palaeolimnology, palaeoclimatology, environmental changes, Holocene, Arctic
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New achievements in sedimentary geology of the western part of the Bohemian Cretaceous Basin
Uličný, David ; Laurin, Jiří
Since the Late Cenomanian time the shallow seaway of the Bohemian Cretaceous Basin facilitated water-mass transfer across the nortehn part of the Bohemian massif. Marine currents flowing along the seawaz axis strongly influenced the deltaic deposition at basin margins. We interpret the narrowing of the seaway between the Czech and Saxonian parts of the basin as the main cause of vigorous tidal circulation. Acceleration of tidal currents in this region is reproduced also by numerical modelling of tidal circulation performed at the Imperial College (London) on the basis of our data.
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