National Repository of Grey Literature 22 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Adaptation of parasitoids used during host utilization in the Chalcidoidea superfamily (Hymenoptera)
Ročková, Lenka ; Janšta, Petr (advisor) ; Holý, Kamil (referee)
The Chalcidoidea superfamily is one of the most diverse groups of parasitic insects. The life strategy prevalent in most species of this superfamily is parasitoidism, which can be used by human as an effective tool in biological control. Parasitoids deal during their reproduction with the fact, that their hosts are often hidden in hardly accessible places. This matter of fact is probably the reason for development of some of the ovipositor's characteristics, that cannot be explained phylogeneticaly. These characteristics are therefore described as adaptations for parasitoid lifestyle. These adaptations mirror the nature of substrate which their hosts inhabitate and where the oviposition is being realised. Species inhabitating the same niche use to show different adaptations of the ovipositor, which could be explained by better distribution of the present resources. It is also considered a speciation factor of sympatric species. Detailed studies of the differences between ovipositor adaptations may simplify the determination procces of life strategies of hymenopteran insects, which could be performed based on ovipositor morphology. Key words: parasitic Hymenoptera, Chalcidoidea, ovipositor structure, hosts seeking, adaptation for host utilization, host discrimination
Evolution of parasitic Hymenoptera hosts specialisation of the genus Torymus
Bubeníková, Kristýna ; Janšta, Petr (advisor) ; Bogusch, Petr (referee)
The genus Torymus (Chalcidoidea: Torymidae) has very diversified parasitic strategies and adaptations to its hosts. Its larvae are ectoparasitoids and attack mostly larvae of various gall wasps (Hymenoptera: Cynipidae) and gall midges (Diptera: Cecidomyiidae). However, few species prefer also other insect groups as a host or are even phytophagous. Many hypotheses concerning evolution of insect host associations were published, but have not been satisfactorily tested using parasitic insects as a model. In this thesis I studied coevolution of the genus Torymus and its hosts. The main questions are what kind of host shifts occurred during the evolution of host strategies and whether sister species of parasitoids are specific to the related hosts/or nonrelated hosts living in the same type of habitat. I also studied changes at morphological adaptations to its hosts. To test critically these hypotheses, I constructed phylogenetic tree of selected Torymus species based on 5 genes and compared their host association within and between clades of Torymus. Key words: Torymus, Chalcidoide, parasitoid, phylogeny, host specialisation
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
Phytophagy as an alternative feeding strategy of parasitic Hymenoptera larvae
Böhmová, Julie ; Janšta, Petr (advisor) ; Skuhrovec, Jiří (referee)
Parasitoidism is considered to be the primary larval feeding strategy of parasitic Hymenoptera (Hymenoptera: Apocrita: Parasitoida). However, many species became secondarily phytophagous, in particular some species of Ichneumonoidea, Cynipoidea and Chalcidoidea. The bachelor thesis summarizes the knowledge about phytophagy in these superfamilies and divides them into four categories. The thesis further evaluates morphological and behavioural adaptations related to this way of life as well as other aspects of their coevolution with host plants.
Flow cytometry and its use for study of insects
Stuchlíková, Magdalena ; Janšta, Petr (advisor) ; Sadílek, David (referee)
Flow cytometry is a modern technique in research, playing a significant role in biomedicine and botanics. Despite its benefits (speed, simplicity, low costs), flow cytometry is currently not used in the study of insects on a large scale. This thesis gives an overview as to how flow cytometry is used in research on insects and summarises the results of such study. This pertains to genome size and its connections to other phenomena. Other focal points of research, such as ploidy and base pair ratios, are addressed to a lesser extent. Key words: flow cytometry, use in study of insects, genome size, ploidy, invertebrates
Spatial Variability in Pollination Networks
Hadrava, Jiří ; Janšta, Petr (advisor) ; Keil, Petr (referee)
Plant-pollinator interaction assembly can be represented as so called pollination network. Using these networks, assembly of plant-pollinator communities and geographic patterns in pollination networks can be studied. During last years, a great progress in describing patterns in structure of plant-pollinator interaction webs and in describing their spatial variability was made. However, these results are mostly based on data from previous studies, which are not seamlessly comparable due to their nonuniformity. My thesis aims at the methodological concepts of study on pollination networks. Based on meta- analysis of previously published data and on data from four years detailed study of plant-pollination system from one locality, I show several methodological problems caused by dissimilarities in sam- pling method of current pollination-network data. These dissimilarities could be responsible for some observed patterns in the assembly of pollination networks. Thus, I propose a uniform method for observing pollination networks suitable for macroecolo- gical meta-analyses (pollination network samples). I tested this method in the field and I described 49 pollination networks from the central and eastern Europe by using such method. In these ne- tworks, no nonrandom structure character such as...
Spreading of praying mantis (Mantis religiosa) in Europe
Vitáček, Jakub ; Janšta, Petr (advisor) ; Gvoždík, Václav (referee)
Climate change is one of the most important factor determining species ranges. In Europe there is now evidence for northward areal expansion in many Mediterranean insects including the praying mantis (Mantis religiosa). This species is the only representative of the order Mantodea inhabiting central Europe. The northern edge of the species distribution currently reaches latitude 53ř North. Although, the praying mantis is well known insect there is not enough evidence about its phylogeography. In this work three mitochondrial genes (COI, COII, Cyt b) were selected for phylogenetic study. Results indicate three statistically supported distinct lineages in Europe: Eastern European, Central European and Western European. Presumably these lineages are consistent with isolation during the last glacial and re-colonization from glacial refugia. Reduced haplotype diversity on the northern edge suggests currently established populations at the northern distribution border. To validate mtDNA results it was also considered four microsatellite loci. Due to different type of inheritance mtDNA and nuclear DNA it is possible to compare two independent genetic datasets. Microsatellite analysis confirmed results obtained on mitochondrial data. Three major genetic clusters were found: east, west and central. Spatial...
Parasitoid hymenoptera hosts specialisation and defensive mechanisms of their host species
Bubeníková, Kristýna ; Janšta, Petr (advisor) ; Holý, Kamil (referee)
Parasitoids (Hymonoptera: "Parasitica") are very large group of insects. Their diversity is also enormous in various morphological adaptations and hosts specialisations. The bachelor thesis summarize particular types of host specialisations and compare generalits and specialists from taxonomical, ecological, evolutionary and geographical point of view. The thesis include summary of theories concerning host-defence adaptations against parasitoids (i.e. morphological adaptations, space-time adaptations) as well. Key words: Apocrita, specialist, generalist, defensive mechanism, evolutuion
Tribe Microdontomerini (Hymenoptera: Chalcidoidea: Torymidae) - phylogeny and evolution
Stiblík, Petr ; Janšta, Petr (advisor) ; Bogusch, Petr (referee)
Superfamily Chalcidoidea (chalcid wasps) represent the most species-rich group of the Hymenoptera and includes 22 families. Family Torymidae is one of those families and it's monophyly is currently intensively discussed. This particular thesis aims at the tribe Microdontomerini (Torimidae: Toryminae). Species of this tribe are usually minute inconspicuous wasps (body length ranges from 2 to 4 mm). Recent progress in phylogenetics of chalcid wasps allowes us to formulate robust hypothesis of Microdontomerini evolution, as a component of broader study of Chalcidoidea phylogeny and classification. My approach combines molecular and morphological evidence to formulate the most plausible evolutionary scenario. Dataset of 35 mostly morphological characters for 33 taxa including all existing Microdontomerini genera and 10 outgroups has been scored. Almost all characters has been studied and documented using Hitachi S-3700N-VP scanning electron microscope. In 117 taxa, 5 nuclear genes segments (18S, 28SD2, 28SD3-5, EF1alfa, Wingless) and 3 mitochondrial genes segments (COI-LCOHCO, COI-JerryPat, CytB) were sequenced, to get together the final molecular dataset of 387 Kbp. Molecular trees were built using maximum likelihood and Mr.Bayes algorithms. Evolution of morphological characters were mapped on the...

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