National Repository of Grey Literature 44 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
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)
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).
Ontogeny of exaggerated structures in dung beetles (Coleoptera: Scarabaeinae)
Žídek, Radim ; Šípek, Petr (advisor) ; Hanus, Robert (referee)
E n g l i s h a b s t r a c t Horns of scarab beetles represent a secondary sexual characters present mostly in males, to whom they serve as weapons in combats over the acces to females. In many species, two discrete male forms occur, "horned" and "hornless", which employ different reproductive strategies. Adult body size and horn morphology are determined by nutritional conditions encountered by larvae during their development. Switching between developmental pathways is accomplished by circulating levels of juvenile hormone (JH) which reflect body size, and genetically determined threshold of sensitivity to it. When body size is larger then threshold, horn growth occur, whereas if it's not, a brief pulse of ecdysone reprogramme the development and hornless adult emerge. Reprogramming the development encompass modifications of the insulin receptor pathway as well as changes in exact domains of genes expression envolved in specifying the proximodistal axis of the developing horn. Development of horns is morphologically reminiscent that of other insect appendages, with which it shares the expression of genes wingless, decapentaplegic, Distal-less, dachshund, homothorax, aristaless and EGFR, parts of gene regulatory network ensuring origin of the outgrowth of the cuticle. Some of them are expressed through...
Succession and sezonality of necrobiont insects communities on carcasses of small mammals
Mikátová, Šárka ; Šípek, Petr (advisor) ; Šuláková, Hana (referee)
The presented master thesis describes the changes of insects communities on carcases of small mammals in course of the decay. We focused both on aspects of (temporal) succession as well on season dependent differences in carrion insect community. The study was carried out during the seasons 2014 and 2015; in each of the years we used a different carrion type (2014: mice (Mus musculus) +/- 20g, 2015: brown rat (Rattus norvegicus) 400-500g). Because we wanted to record the actual successional stage, we used a "walk-through" type of traps instead of commonly used pitfall traps. The general succession pattern was similar in both seasons; however the succession course of brown rat carcasses was slightly delayed. The succession was strongly influenced by the first species colonizing the carrion and morover, most of the carcasses were dominated or monopolized by a single species (or species group). Only the carcasses of mice were buried by the burying beetles (Silphinae: Nicrophorus). Bow flies (Calliphoridae) have been identified as the most common members of carrion insect communities. The other important members were the flesh flies (Sarcophagidae), and beetle families Silphidae and Staphylinidae. The highest abundance of insect was observed in summer, lowest abundance either in spring or fall depending on the...
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...
Beetles on carrion: life strategies and ecological classification
Kadlec, Jakub ; Šípek, Petr (advisor) ; Růžička, Jan (referee)
This work summarizes available information about beetle communities on carrions, their life strategy and ecology classification. Necrobiotic beetles are very important part of the decomposition process and the return of organic mass to the life cycle. We can classify decomposition by several criterions, most commonly by the overall appearance of the carrion and by the species of present insect. Conclusions are different depending on authors. Process of decomposition of carrion is affected by the readiness of access for different species of insect. Insect succession depends on many factors, some factors increase the process and others decrease it. The interrelationships between different colonizators of carrion are very important, this relationship is described by three models of classic success ecology. Necrobiotic insect has specific adaptations for the life on carrion. For this thesis, we have chosen 13 families, which are often discussed in publications. The rest of 190 necrobiotic genuses from 34 families is listed in this thesis with their characteristic ecology.
Larval morphology, phylogeography and automatic identification of chosen flower chafer beetles (Scarabaeidae: Cetoniinae)
Vondráček, Dominik ; Šípek, Petr (advisor) ; Bezděk, Aleš (referee) ; Kundrata, Robin (referee)
Currently, over 4.300 species of flower chafer beetles (Scarabaeidae: Cetoniinae) are described in more than 485 genera, with the number of genera, species and subspecies increasing by dozens of new taxa each year. Especially in the past, some of the species descriptions were relatively vague and short operating only with the coloration of beetles, or with extremely subtle differences on the male genitalia without any support of other data and analyses. In this dissertation, I focused on the use of various data and methodological approaches that can help understand the evolutionary processes within this group and its complicated taxonomy and systematics, which is also still very unstable even at higher taxonomic ranks. In two works we studied the morphology of immature stages of flower chafers and their bionomy. In the case of the Taenioderini tribe, whose immature stages were not known until then, we found surprisingly significant morphological variability in the eight described species, which is unusual in larval stages of flower chafers. In the second work, we focused on the genus Oxythyrea. We described the larvae of nine of the ten currently known species and confronted the obtained data with the already existing descriptions of the larvae of the Leucocelina subtribe, to which the studied...
The distribution and role of UV reflectant patterns in Scarab beetles (Coleoptera: Scarabaeidae)
Vlach, Jan ; Šípek, Petr (advisor) ; Kleisner, Karel (referee)
The diploma thesis is focused on the distribution and role of UV reflectant patterns in beetles (Coleoptera) with focus on the family Scarabaeidae. Through a survey of European museum collections, we discovered over 900 species of UV reflectant beetles, of which 850 species were identified as UV reflectant for the first time. The surface structures responsible for UV reflectant patterns in beetles were studied in detail using a scanning electron microscope. We have identified two ways how the UV reflectant patterns occur. The first way: the light rays interact with the internal structure of the cuticular formations or the cuticle itself; the second way: the light rays interact with the surface layer formed by cuticular secretion. Additionally we carried out experiments with live animals, where we investigated the effect of an individual's age on the intensity of UV reflectant patterns and the effect of UV reflectance on reproductive activity. In a pilot study we were able to show that freshly hatched individuals show a higher level of UV reflectance than older individuals.
Biodiversity of green roofs
Matoušková, Kateřina ; Sedláček, Ondřej (advisor) ; Šípek, Petr (referee)
Green roofs offer interesting multifunctinaly solutions to many problems at once. In a small area they bring benefits to people and nature. They thermally insulate buildings, improve the local microclimate and reduce the city's heat island efect. Green roofs improve air quality and also help retain water in the landscape. In combination with solar panels and retention tanks, green roofs can contribute to the modern trend of building green - sustainable - buildings. Green roofs can be used for growing food sources and for relaxation as well. Wild plants can spontaneously colonize green roofs and thereby expand their habitats in cities. The plants create habitats for many animals (especially invertebrates) and provide nectar sources to pollinators. Except food habitats, they offer birds habitat for nesting and resting place during their migration. The aim of this thesis was to evaluate the contribution of green roofs to urban biodiversity. At present, howewer, most scientific studies deal with the advantges of green roofs in connection with enviromental protection or the technical side. A small part of the studies examines the biodiversity of green roofs. My goal was to find out which factors influence a biodiversity of green roofs the most and to design an ideal roofs solution with the greatest...

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