|
|
Problematika invazních druhů raků na území České republiky
Čuprová, Veronika
The diploma thesis following the bachelor thesis "Invasive species in the Czech Republic" is focused on the issue of invasive species of crayfish. The aim of the thesis is to describe the legislation, the current method of monitoring these species and the possibilities of their regulation. The thesis deals with the monitoring of invasive crayfish species at two selected sites in the Czech Republic and the application of appropriate regulatory interventions. Along with the monitoring, water samples were taken and analyses for the presence of crayfish plague were carried out. The results show that at the Prostřední rybník site, where the marbled crayfish occurs and where eradication measures have been underway since 2020, it has still not been completely successfully eradicated. From the interview conducted with local respondents, it was found that about half of the respondents are aware of this issue, thanks to the actions carried out to eliminate this species and the information boards posted in the area. In addition to the signal crayfish, a small population of the native endangered river crayfish is also present at Besének. Regulatory measures have also been implemented at this site in order to eliminate this invasive species as much as possible and to prevent potential threats to the native crayfish. Based on the results obtained, further possible control measures were proposed at both sites. In the future, more focus should be placed on education of this highly topical issue, as public awareness and understanding is considered one of the most effective preventive measures.
|
|
|
Tajemství chemické komunikace u raků - přehledová studie a metodické cesty
ERBAN, Pavel
Chemical communication is one of the most important aspects of crayfish life and this is the most effective way of communication for them. Thanks to it, crayfish can effectively transmit information in a complex aquatic environment. Crayfish use chemical communication when interact in the environment, during building a social hierarchy, aggressive behaviour or during maternal care. The aim of this work was to create a concise literature review on known aspects of chemical communication in crayfish, together with testing urine sampling methods and their functionality. The methods used were confirmed to be functional and usable for further sampling with methodological notes and adjustments. In accordance with our results, it was evident that the amount of urine samples was lower when crayfish underwent previous interactions. For marbled crayfish, a positive linear trend of the samples size was visible with increasing weight and cephalothorax length of individuals. For signal crayfish, this trend was not evident for crayfish without previous interactions. This bachelor thesis forms the basis for further study of chemical communication in crayfish and at the same time offers a first confirmation of a functional method of urine sampling from crayfish for its further chemical analyses.
|
|
|
Crayfish as a Model Taxon in Primary and Secondary School
Kostřicová, Zuzana ; Hanel, Lubomír (advisor) ; Andreska, Jan (referee)
This thesis brings a review of the crayfish topic. It aims to be useful for teachers who decide to explore the topic deeper with the class. The theoretical part stars with crayfish seen from the historical and cultural point of view and crayfish as an important source of food for humans. In the following chapters, systematics and global distribution of crayfish is disscused as well as their morphology and anatomy with the aim to highlight facts, that can be used in lessons. After that, six species living in the Czech republic are introduces, all the native species and signal crayfish, spiny-cheek crayfish and marbled crayfish. Than we focus on the position of crayfish in food webs and also on all factors that threaten the populatons of native species: influencing and regulating the riverbeds, competition with invasive species (vectors of crayfish plague), other parasites and pathogenes and also the influence of drought and the climate changes. The last chapter of the theoretical part discusses the different approaches to crayfish protection, repatriation of the native species, but also the approaches which aim to limit the spreading of invasive species including their elimination. In the research part, the content of various biology textbooks was analysed. The aim was to find out how these...
|
|
|
Pach vítězství: role feromonů v interakcích raků
MAREŠ, Josef
Analysis of communication, hierarchy, and role of pheromones in crayfish is an interesting area that constantly brings new knowledge and can help us understand some facts that may be valid not only for crayfish but also other crustaceans. In this work, it was therefore studied how the offspring of two females behave in a one tank. After the dominance establishment in females (after a series of contacts and fights), the offspring of preferred a dominant female only, regardless of if their own or a unfamiliar mother. The dominant female, that successfully fought the fights, collected juveniles by its active movement, and they followed its movements. The subordinate female accepted her position, tried to avoid contacts, and reduced its activity. The juveniles practically ignored the subordinate mother at this stage of the experiment. Within the diploma thesis, all set goals were achieved and the newly discovered facts may be an important part of further follow-up experiments. We were able to respond positively to all primary hypotheses when: 1 / Females of marbled crayfish in one tank always established a relationship of the dominant and subordinate one, 2 / marbled crayfish juveniles always chose only one mother in a common tank, and 3 / it was in all cases the dominant one. The results show that dominance (whether communicated chemically or by visual stimuli) is a more important factor for juvenile crayfish than the specific brood pheromeone of their mother. The results bring significant knowledge to the issue of the hierarchy of various chemical and visual signals in crayfish communication. Thus, certain communication signals seem to be superior to others. The "winner odours" are probably stronger than such a strong stimulus as the brood pheromone responsible for recognizing the offspring and the mother. On the other hand, it is not possible to rule out a possible effect of the unattractiveness of the subordinate mother. How the relationships among the subordinate female, dominant female and their offspring would develop in remains opened to further research hypotheses.
|
|
|
Phylogeography and genetic variation of benthic crustaceans in European inland waters
Pešek, Pavel ; Petrusek, Adam (advisor) ; Sacherová, Veronika (referee)
This thesis summarises published information about geographic distribution of genealogical lineages and genetic variability of benthic crustaceans of European continental waters, and evaluates the historical factors that affected their distribution. it is focused mainly on species for which multiple or in-depth studies have been published. A particular attention is given to crayfish of the genus Austropotamobius. Present distribution of genealogical lineages has been affected by changes in connectedness and availability of aquatic habitats. Species lineages often split in consequence to geological and climatic processes during the Tertiary, as exemplified on species complexes of Austropotamobius crayfish, species lineages of the amphipod Gammarus fossarum species complex, and the isopod Asellus aquaticus. The distribution of intraspecific lineages has been strongly affected by Quaternary cycles of glaciation, which not only destroyed many habitats by moving glaciers but also created new colonisation routes. Such routes were peri-glacial lakes, which had been used by Gammarus lacustris, or retreat of sea level, which enabled white-clawed crayfish to colonise England, and a freshwater crab to colonise Italy. Changes in sea levels are also the likely reasons for colonisation of continental waters by the...
|
|
|
Porcelain disease in crayfish: biology, impacts and distribution
Jelínková, Tereza ; Balcarová, Eva (advisor) ; Vávra, Jiří (referee)
The porcelain disease is a disease affecting crayfish caused by the microsporidium Thelohania contejeani. This intracellular parasite attacks muscle cells of the host and fills them with spores. This leads to white or opaque colouration of the abdominal muscle of crayfish, which is characteristic for this disease. The parasite gradually attacks more muscle fibers which probably leads to decrease of locomotor activity of affected crayfish and finally may result in their death. T. contejeani at low prevalences does not represent a real danger to crayfish populations and thus it is not as serious threat as crayfish plague. However, it has been associated with several cases of mass mortalities too. This thesis summarizes essential findings about infection by this parasite, analyzes its impacts to the host and factors that can influence transmission and progress of this disease. It also describes a life cycle of T. contejeani, summarizes records of the occurrence of this parasite and evaluates risks which it poses to crayfish populations. Finally, methods used to detect infection are described. Keywords: Thelohania contejeani, porcelain disease, crayfish, microsporidia, parasite, muscle
|
|
|
Factors influencing diurnal activity of crayfish and its seasonality
Plasová, Kateřina ; Petrusek, Adam (advisor) ; Buřič, Miloš (referee)
Crayfish is mainly but not exclusively a nocturnal animal. The crayfish aktivity is taxon specific and can be further affected by various factors. The aim of this thesis is to create an overview of factors affecting the activity and to summarize their impact. Factors can be divided into those influencing daily activity and those influencing seasonal behaviour. This thesis focuses on discussing different reactions to the factors and its intensity by individual species. Insufficient data covering activity during the winter season offers an opportunity for further research. Key words: crayfish; daily activity; abiotic factors; biotic factors; seasonality
|
|
|
Use of environmental DNA for detection of aquatic invertebrates
Bílek, Marek ; Petrusek, Adam (advisor) ; Černý, Martin (referee)
Environmental DNA is released genetical information from the individual to the environment. Especially in the aquatic environment, the amount of detectable DNA is sufficient to prove or refute the presence of a target organism. The method of taking samples from an aquatic environment and working with DNA is constantly evolving and bringing new insights. Especially in the area of aquatic vertebrates, very good results are found. Especially in actual researches results often correspond to reality more than traditional methods of capture. In contrast, research of an aquatic invertebrates by detection of eDNA is overlooked, especially because of eDNA production by invertebrates, which is generally much lowerthan fish andamphibians production. In this case the largest amount of eDNA is released in the form of mucus. In this work I focus on properties of eDNA in the aquatic environment, biotic and abiotic factors that affect the durability of detectable DNA. I also mention the production of DNA of aquatic invertebrates, the possibilities of collection and the laboratory procedures of its processing, I compare the different approaches of the scientific teams in the referenced research and draw attention to the most frequent problems. At the end of the thesis I compare the results of the current research...
|
|
|
Porcelain disease in crayfish: biology, impacts and distribution
Jelínková, Tereza ; Balcarová, Eva (advisor) ; Vávra, Jiří (referee)
The porcelain disease is a disease affecting crayfish caused by the microsporidium Thelohania contejeani. This intracellular parasite attacks muscle cells of the host and fills them with spores. This leads to white or opaque colouration of the abdominal muscle of crayfish, which is characteristic for this disease. The parasite gradually attacks more muscle fibers which probably leads to decrease of locomotor activity of affected crayfish and finally may result in their death. T. contejeani at low prevalences does not represent a real danger to crayfish populations and thus it is not as serious threat as crayfish plague. However, it has been associated with several cases of mass mortalities too. This thesis summarizes essential findings about infection by this parasite, analyzes its impacts to the host and factors that can influence transmission and progress of this disease. It also describes a life cycle of T. contejeani, summarizes records of the occurrence of this parasite and evaluates risks which it poses to crayfish populations. Finally, methods used to detect infection are described. Keywords: Thelohania contejeani, porcelain disease, crayfish, microsporidia, parasite, muscle
|
|
|
Usage of dissection of invertebrate animals in education of biology at secondary school
Ondrová, Radka ; Mourek, Jan (advisor) ; Říhová, Dagmar (referee)
The thesis is focused on anatomy and implementation of dissections of 4 selected model invertebrates in school practice. The selected model species include swan mussel (Anodonta cygnea), stick insect (Medauroidea extradentata), cockchafer (Melolontha melolontha) and sea urchin (Echinus esculentus). In case of the cockchafer, the text is based on this model species, but the supporting photographs of dissection are taken from the tropical cetoniid beetle Pachnoda, which has very similar internal anatomy with the cockchafer. For all selected animals, I describe external and internal morphology as well as recommended methods of obtaining the material, proper killing of specimens, and dissection techniques. The text is supplemented with original digital macrophotographs. The thesis includes also an overview of primary and secondary school textbooks with focus on anatomy of the selected animals. The text is supplemented by a glossary of morphological terminology used in this thesis. Attached is a photographic atlas of dissections, which is a combination of this master thesis and my bachelor thesis (defended in 2010), in which I dealt with five model invertebrates in the same way. This is Ascaris suum, Lumbricus terrestris, Helix pomatia, Procambarus aff. fallax and Archimandrita tesselata. The complete...
|
guest ::
