National Repository of Grey Literature 24 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Conservation of populations on the edge of geographical distribution
Pešová, Lucie ; Sedláček, Ondřej (advisor) ; Šípek, Petr (referee)
Populations on the edge of the range are often considered less valuable for conservation with regard to core populations of the species. These populations are often small, isolated and less genetically variable, and are therefore more prone to extinction. On the other hand, there are some studies claiming that some peripheral populations could have genetically unique allels which could help them adapt to changing environmental conditions. They thus have a big speciation potential. Peripheral populations could also occur behind state borders, where the species has conservation status, despite the fact that it is a common species somewhere else in its range. Due to this contradiction, peripheral populations are a delicate topic of discussion in the scientific community. In this paper I summarized the features of populations on the edge and also factors which limit them. Furthermore, population dynamics of these populations and summary of the main genetic processes taking place in small populations are outlined here. Next there are arguments for and against conservation of populations on the edge. In conclusion I give model examples of species on the periphery, demonstrating their features and reasons for their possible conservation. Key words: population, conservation, peripheral, marginal, range...
Growth and sexual selection in selected representatives of scarabaeoid beetles (Coleoptera: Scarabaeoidea).
Vendl, Tomáš ; Šípek, Petr (advisor) ; Knapp, Michal (referee) ; Skuhrovec, Jiří (referee)
Flower chafers are well-known beetles with apparent sexual dimorphism. Yet, in contrast to other groups of scarab beetles, only little attention has been paid to various aspects of this phenomenon. It concerns also sexual dimorphism in size, which is very common in animals. Although ultimate causes of sexual size dimorphism have been extensively studied, the developmental mechanisms are still only poorly understood. We investigated proximate causes of sexual size dimorphism in several differentially dimorphic flower chafer species. We found that in highly dimorphic species the dimorphism started to develop already in the first instar and tended to accumulate through successive larval development. In contrast, the sexes in species with a relatively low dimorphism diverged in size during only one instar. Moreover, we found variability not only in when the dimorphism arises during development, but also how: sex-related differences in both the instar duration and average growth rate were the proximate causes of sexual size dimorphism. In addition, we showed that the sexes may differ also in growth trajectory - males had relatively longer period of rapid growth than females, even in cases where the absolute development times were similar in both sexes. Further, we focused on systematic survey of sexual...
Influence of neonicotinoids on insect communities with focus on bees
Weingartová, Barbora ; Erban, Tomáš (advisor) ; Šípek, Petr (referee)
The bachelor thesis is focused on pesticides and their impact on the environment. Plant protection products must undergo a comprehensive assessment involving the impact on nontarget organisms. Negative effects of pesticides are not only assessed in humans and other vertebrates but also in invertebrates. Pollinators that play a vital role in ecosystems are an important group for evaluation. This thesis specializes in a group of pesticides called neonicotinoids, some of which are currently banned in some countries. This thesis mentions array of neonicotinoids, their toxicity and effects on pollinators that were observed. Reassessment is crucial in order to make a comprehensive picture of whether the ban was correct. . Keywords: pesticides, neonicotinoids, pollinators, honeybees, bumblebees, colony collapse disorder
Biogeography of the Balkan Peninsula: geological development and recent state of knowledge
Žďárská, Kateřina ; Šípek, Petr (advisor) ; Král, David (referee)
The aim of this study is to summarize history and development of Mediterranean with a following description and comparison of the biogeographical regions of the Balkan peninsula and surrounding areas. Balkan peninsula is located in eastern-central Mediterranean, which is known for its complex paleogeographic evolution. Current presence and distribution of organisms with high rate of endemism is influenced by several factors. For example orogenesis, the fragmentation of the Tethys ocean in Miocene (16 - 18 Ma), the birth and progression of the Paratethys sea and the Messinian salinity crissis (MSC, 5.97 - 5.33 Ma), followed with enormous ecological changes in whole Mediterranean. In this period, landbridges were formed and they allowed migration of species between African, Arabian and Eurasian tectonic plate. Another important period that formed present Mediterranean is Quarternary period in which this area is influenced by climatic oscillations leading to alternation of glacial and interglacial phases. Simultaneously, the sea level oscilations and migrations of species occured, which resulted into the creation of various refugia.
The study of chemical ecology in necrophagous insects: a summary of methodology and technical approaches.
Száková, Barbora ; Šípek, Petr (advisor) ; Jakubec, Pavel (referee)
Carrion insects have irreplaceable role in nutrient cycle. They are able to locate a carcass within a few minutes and colonize it. Insect's orientation is enabled mainly by smell, primary sensory receptors are placed in antennae and maxillary palps. Perception research of chemical signals is done by biotests, which are testing behavioral responses, or by methods measuring physiological response such as electroantennography (EAG). To analyze volatile organic compounds are used gas chromatography and mass spectrometry (GC-MS).
Stable isotopes and the study of insects ecology
Javůrková, Jaroslava ; Šípek, Petr (advisor) ; Harant, Karel (referee)
Animal foraging ecology is an important part in the puzzle ecosystem relationships. This bachelor thesis presents review in the field of food ecology, especially insects. It focuses on the method of analysis of stable isotopes, which is one of the current and in recent decades a modern approach for studying this issue. Stable isotope analysis is compared with other frequently used methods for animal food ecology. The aim of this work is to introduce this method and its possible use in the study of insect food ecology. The first part provides the necessary theoretical background, practical application in laboratory and then it deals with the problems typically adressed by this method. Key words: stable isotopes, stable isotopes analysis, food ecology, food preferences, insects
Experimental Electro-Mechanical Musical Drum Instrument
Šípek, Petr ; Schimmel, Jiří (referee) ; Dlouhý, Dan (advisor)
The aim of the bachelor thesis is to design and create an experimental mechanic-electrical drum instrument, namely a hybrid percussion instrument, using various resonant materials and oscillators supplemented by mechanical tuning in the main part of the instrument. Part of the instrument will consist of a series of piezoelectric transducers scanning individual segments of the musical instrument. It will be possible to edit each individual created sound by using effects.
Larval morphology of Goliathini (Coleoptera: Cetoniinae) and its contribution towards the understanding of the group's evolution.
Kouklík, Ondřej ; Šípek, Petr (advisor) ; Skuhrovec, Jiří (referee)
1 Abstract Currently there are almost 4000 described species of rose chafers (Scarabaeidae: Cetoniinae) but larvae of less than 200 species are described. In this work we studied larval morphology of 86 species belonging to 58 genera with focus on the tribe Goliathini. The larvae of 21 genera were studied for the first time. 77 morphological characters on head, mouth parts, legs and thoracal and abdominal segments were studied. This resulted into large matrix of morphological characters, which were further tested in separate phylogenetical analyses. A checklist of studied characters and their states and also large databasis of photographs of the characters are also amongst the results of the thesis. Five independent datasets were tested, three were based singly on morphology, one on molecular sequences and one on a combined dataset. The phylogenetic analysis was made by three methods, maximum parsimony, maximum likelihood and bayesian interference. Eleven different phylogenetic trees were obtained as a result, based on which we tried to reconstruct the relationships between the inner groups of Cetoniinae with focus on relationship of subtribes of tribe Goliathini. Monophyly of the tribe Goliathini as well as some other groups could not be confirmed, as well as the alleged basal position of the genus...
The role of iridescent and UV reflectant coloration patterns in beetles (Coleoptera)
Vlach, Jan ; Šípek, Petr (advisor) ; Pecháček, Pavel (referee)
The bachelor thesis deals with the role of iridescent and UV reflectant coloration patterns in beetles (Coleoptera). The thesis is divided into two main parts. The first part describes in detail the different types of iridescent and UV reflectant coloration patterns, it deals with the physical origines of coloration and finally it presents examples of beetle species, which possess this types of coloration. The second part deals with the functional perspective of iridescent and UV reflectant coloration patterns. The coloration function is divided into visual and nonvisual part. The part dealing with visual function is focused on interspecific and intraspecific communication, while the part dealing with nonvisial function describes thermoregulation and mechanical function of coloration. Powered by TCPDF (www.tcpdf.org)
Factors affecting the composition of insect communities on carcases of small mammals
Máslo, Petr ; Šípek, Petr (advisor) ; Čížek, Lukáš (referee)
This thesis describes invertebrate community on cadavers of small mammals, in particulat how cadaver size influences abundace, density, species richness and composition of the necrobiont community. Cadaver size preference of present insects is also described. Field experiments were performed in 2014 in meadow habitats in spring, summer and autumn season. Cadavers were chosen in three weight groups: mice (20 g), small rats (100 g) and large rats (400 - 500 g). Invertebrate abundance increases with cadaver mass, density of the community remains constant. Larger cadavers also have higher species richness. Most dominant ecological guild are necrophages, represented mosty by blow flies (Calliphoridae). Cadaver size preference of recorded insects differ, necrophagous and predatory taxa tend to prefer larger cadavers. Omnivorous carrion beetles (Silphidae: Nicrophorus) prefer small cadavers. Sex of the carrion beetles (Silphidae) does not affect their cadaver size preference, males and females of particular species have very similar preferences. Keywords Ephemeral resource patch, cadaver, necrobiont, size, abundace, diversity, competition, insect communities

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1 Šípek, Pavel
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