National Repository of Grey Literature 37 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Comparative analysis of working age population mortality in selected developed countries
Straka, Jakub ; Burcin, Boris (advisor) ; Rybová, Kristýna (referee)
Comparative analysis of working age population mortality in selected developed countries Abstract The main aim of this thesis was to analyze trends in mortality situation of working-age population (20-64 years old) in 31 developed countries in period 1995-2010 and to find similarities and differences between them. Temporary life expectancy was used as an indicator which summarizes the intensity of mortality in productive age. One-dimensional and two-dimensional decomposition revealed the contributions of individual age groups and selected nine major groups causes of death defined by ICD to the difference in temporary life expectancy values between 1995 and 2010 in five selected countries. An analysis of the development of this indicator has shown that there has been a prolongation of life span in working age in all surveyed countries and differences in mortality rates between countries decreased. Major cause of this trend was probably reduction of the mortality rate in the middle-aged population, mainly of external causes, in the 20-54 age group in countries with lower life expectancy rates. However, to verify this hypothesis, it would be necessary to analyze other developed countries with a higher level of mortality in working age population than Bulgaria and Lithuania. Countries with higher temporary life...
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
Reintroduction of butterflies (Lepidoptera)
Štochlová, Tereza ; Sedláček, Ondřej (advisor) ; Straka, Jakub (referee)
The thesis deals with one of the active means of conservation - reintroduction. By this ap- proach, organisms are released in their historical range from which they have disappeared. Re- introductions typically concern vertebrates, that is, however, why this thesis focuses on a group of invertebrates - butterflies (Rhopalocera). The main aim of this work is to carry out a research of previous experiments, evaluate used methods and discover the best way to proceed with reintroduction of butterflies. This process contains many important steps. Firstly, a suitable species must be chosen, that means one that is declining and has limited dispersal abilities. Secondly, an appropriate habitat for releasing organisms must be found - host plants ought to be sufficiently abundant and the area big enough. If the habitat quality is not satisfactory, it can be achieved through management, most commonly by planting host plants, mowing or grazing. Next step is choosing the right donor population. It should be stable, genetically variable, and genetically and ecologically related to the original extinct population. After transfer and release of sufficient number of organisms, it is crucial to carry out a long-term monitoring of the newly formed population and to modify its management when necessary. All methods...
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...
Bee phylogeny (Hymenoptera, Anthophila)
Jindrová, Lenka ; Straka, Jakub (advisor) ; Astapenková, Alena (referee)
As a result of a new methods and a mount and availability of molecular data, we changed our understanding of phylogeny of many groups, of course the phylogeny of bees too. In the past, only the morphological data were used to find out the relationships between taxa. Today, we use molecular data, which can be combined with morphological knowledges. Because of using the molecular biology methods, we can solve the relationships among taxa more precisely. This work summarizes present view on phylogeny bees with a look at history of bee classification and evolution of some characters, for example host plant specialization and more. The position of bees in the superfamily Apoidea is also described in this work
Strepsiptera and their host specialization
Jůzová, Kateřina ; Straka, Jakub (advisor) ; Malenovský, Igor (referee) ; Pohl, Hans (referee)
Strepsiptera, as obligate parasites, have to face the constant selective pressure from their hosts. For this reason, high host specificity and many peculiar autapomorphies have developed in this group. Only a little attention has been paid to the study of phylogeny within particular families of Strepsiptera. Without knowledge of a species concept, it is difficult to estimate different evolutionary scenarios of host-parasite relationships, especially when the species concept is used inconsistently. This situation is made even more difficult by the potential presence of cryptic species or species incorrectly synonymized. Therefore, we focused to the most diversified family of Strepsiptera - family Stylopidae which parasitizing bees (Anthophila: Andrenidae, Colletidae, Halictidae, Melittidae). As a model genus for our phylogenetic studies, we choose the genus Stylops Kirby, 1802 with holarctic distribution, whose representatives are parasites on bees of the genus Andrena Fabricius, 1755. Using the methods of molecular phylogeny, we created the first phylogenetic study of the genus Stylops. Following the results, we could outline the approximate boundary for species delimitation and thereby critically resolve the confusing situation in the species diversity of this genus. Then we mapped the host...
Evolution of host specificity and phylogeography of Strepsiptera parsites of the family Xenidae
Benda, Daniel ; Straka, Jakub (advisor) ; Malenovský, Igor (referee)
The twisted-wing parasites (Strepsiptera) are an endoparasitic order of insects with cosmopolitan distribution, which are sister group of Coleoptera. There are about 600 known species up to date. Strepsiptera parasitize seven insect orders (Thysanura, Orthoptera, Blattodea, Mantodea, Hemiptera, Diptera, Hymenoptera). The family Xenidae is one of the most derived groups of Strepsiptera. Its representatives parasitize aculeate Hymenoptera of three families (Vespidae, Sphecidae, Crabronidae). In comparison to the basal groups, there are well-known hosts for genera of the family Xenidae. Therefore, this group is suitable object for study of the evolution of host specialization. Phylogeny of the family Xenidae was constructed on the basis of molecular analysis of three genes. Moreover, the mapping of ancestral host major groups and biogeographic areas was performed using two methods (parsimony, maximum likelihood). According to the results, the family Xenidae is monophyletic group with Old World origin. There were a several independent switches to the same host groups. This significantly changes the existing ideas about evolution of host specialization and requires a taxonomic revision. Within the family Xenidae, there were several cases of dispersal between the Old World and the New World. Furthermore,...
Characteristic population genetics features of animals with parasitic life strategy
Kodejš, Karel ; Straka, Jakub (advisor) ; Synek, Petr (referee)
Organisms with parasitic life strategy are characterized by strong bond to their hosts. Becouse of that can their population history, or more generaly their phylogeny, reflect evolutionary history of the hosts. While with morphological markers alone, coevolution can be examined only at higher, at least species level, the development of molecular techniques, especially usage of selectively neutral markers, provides deeper insight in this problematics. This thesis describes genetic markers used to investigate population dynamics, with emphasis to parasitic animals, and sumarises their advantages, limitations and possible applications. Further it describes statistical methods used in coevolutionary studies, mainly to reconstruct coevolutionary history. It describes basic statistical algorhytms to characterize rate of population subdivision. In the last part it describes parasite and host's life history features, which influence characteristics of coevolution, such as rate of host specificity, complexity of life cycle, host and parasite's mobility, which has impact to final coevolutionary pattern. Keywords: parasitism, population genetics, genetic markers, coevolution, biostatistics, microsatellites
Biogeography and host spectrum of twisted-wings (Strepsiptera)
Benda, Daniel ; Straka, Jakub (advisor) ; Malenovský, Igor (referee)
Twisted-wings (Strepsiptera) are an endoparazitic order of insects with cosmopolitan distribution, which are sister group of Coleoptera. There are 7 known host insect orders. As a group with relatively small number of species (almost 600) and cryptic way of life, Strepsiptera were usually overlooked by entomologists. Majority of publications about Strepsiptera deal simply with describtion of new species. For many taxa of basal families, the host group is unknown, because just free flying male has been collected and described. In contrary, only a female collected with host is known in some species. In derived families Xenidae and Stylopidae (parasitize Hymenoptera: Aculeata), there are known hosts in overwhelming majority of species. Many information about distribution of these groups can be extracted also from publications about hosts, where stylopized individuals are mentioned. Presented thesis summarizes the distribution of Strepsiptera at the level of families and genera. It also provides an assessment of the occurrens of Strepsiptera in different biogeographic regions with focus on their hosts. Keywords: Twisted-wings, Strepsiptera, distribution, parasites, host group, biogeography

National Repository of Grey Literature : 37 records found   1 - 10nextend  jump to record:
See also: similar author names
12 STRAKA, Jakub
6 Straka, Jan
5 Straka, Jiří
3 Straka, Josef
Interested in being notified about new results for this query?
Subscribe to the RSS feed.