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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...
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The red swamp crayfish Procambarus clarkii (Grirard, 1852) and his burrowing ability
PŘECH, Jiří
In Europe, interactions with non-indigenous crayfish species (NICS) pose a great threat to those indigenous crayfish species (ICS). Red swamp crayfish (Procambarus clarkii) is a typical example of an invasive species that threatens European ICS and has superior ability to construct burrows. This paper contains a review on red swamp crayfish with emphasis on its ability to construct burrows. Also a laboratory experiment evaluating the effects of presence/absence of claws on the burrowing ability in this species had been performed.
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The effect of metabolite terbuthylazine-2-hydroxy on early life stages of marbled crayfish
PEŘINOVÁ, Eliška
Terbuthylazine belongs to the group of pesticides on triazine-based for use in agriculture as herbicides. Terbuthylazine-2-hydroxy is the main metabolite of terbuthylazine. The aim of this study was evaluate the effect of terbuthylazine-2-hydroxy on mortality, growth, occurrence the deformations and the development of early life stages, and levels of oxidative stress, assess the activity of antioxidant enzymes of marbled crayfish (Procambarus fallax f. virginalis) and also augment data for assessing the impact of this metabolite on the environment. For assess of effect of this metabolite was used embryo larval toxicity test with crayfish. The effect of terbuthylazine-2-hydroxy was evaluated in four concentrations (0.75 g.l-1, 75 g.l-1, 375 g.l-1 and 750 g.l-1) for 62 days. Terbuthylazine-2-hydroxy in concentrations 375 g.l-1 and 750 g.l-1 caused decrease of activity superoxide dismutase (SOD) and the levels lipid peroxidation (measured as TBARS) and inhibition of growth. Inhibition of growth was also observed in the group exposed to 75 g.l-1 of terbuthylazine-2-hydroxy. Additionally, there was delay in ontogenetic development of crayfish exposed to concentration 750 g.l-1. The real tested concentration of 75 g.l-1 terbuthylazine-2-hydroxy had no effect to monitored indices in the early life stages of marbled crayfish. Terbuthylazine-2-hydroxy caused oxidative damage of cellular lipids and proteins, changes in antioxidant activity, reduction of growth, delay in ontogenetic development of marbled crayfish.
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The effect of metribuzine on oxidative stress and antioxidant enzymes of signal crayfish
LIDOVÁ, Jaroslava
The aim of this study was to investigate effects of the triazine herbicide metribuzine on oxidative stress level and antioxidant enzymes activity in gills, muscle and hepatopancreas of signal crayfish (Pacifastacus leniusculus Dana) and also extension of knowledge about effect of metribuzine on the environment. The experiment took up 60 days. Crayfish were exposured to metribuzine concentrations of 0.52 micrograms.l-1 (real environmental concentration) and 3.06 mg.l-1 (10% 96hLC50) for the first 30 days. Then a second phase followed depuration without metribuzine (30 days). Changes in the oxidative stress level (TBARS), superoxiddismutase (SOD) activity and catalase (CAT) activity were observed in all examined tissues. Changes in glutathionreductase (GR) activity were observed only in hepatopancreas. Chronic exposure of metribuzine demonstrated an oxidative damage of cell lipids, proteins and also changes in antioxidant activity in examined crayfish tissues.The results of this study suggest that crayfish are a very suitable organisms for toxicological tests and simultaneously extend knowledge about effect of metribuzine on the environment.
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Study of the reproductive biology of the crayfish - mating, laying eggs and morphological structure of the male and female gametes
KUBEC, Jan
In the nature, crayfish are represented like predators or a part of food base of some fish. Also in free waters they acts as detrivors and are an important element in the nutrient and energy circle in aquatic ecosystem. The crayfish weren't able to avoid negative impacts of anthropogenic activities such as water pollution and devastation of habitats. For these reasons reproduction of the crayfish is necessary in hatcheries and farms. The main aim of my work was to study the reproductive biology of the crayfish focused on the process of mating, the interval between mating and laying eggs, fertilization and morphological structure of the male and female gametes. Among the secondary objectives there was included using of repeated electrostimulation of the crayfish and the possibility of hybrids of the noble crayfish (Astacus astacus) and the narrow-clawed crayfish (Astacus leptodactylus). The observation of the period of reproduction was realized on representativies of the noble crayfish and the narrow-clawed crayfish throughout natural mating in the tanks. The structure of gametes was observed on the samples taken from thenoble crayfish (Astacus astacus), the narrow-clawed crayfish (Astacus leptodactylus), the signal crayfish (Pacifastacus leniusculus), the red swamp crayfish (Procambarus clarkii) and spinycheek crayfish (Orconectes limosus). The experiments were carried out during the autumn season in 2012 and 2013. The results of observations of the reproduction of crayfish made us clear as for the period and intervals for all phases of the process of mating crayfish. For females the noble crayfish and the narrow-clawed crayfish was found oviposition without the presence of males. Their individual components have been described by using ultrastructure of males and female gametes. Repeated electrostimulation showed at the family Astacidae as a suitable tool for collecting large mass of sperm material. Hybridization experiment proved that it can occur to mate the two species of crayfish in areas where they occur simultaneously. These experiments helped to further knowledge of reproductive biology of crayfish.
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The electrostimulation the spermiation in the crayfish
KUBEC, Jan
The crayfish are important and indispensable animals in aquaculture. In the aquatic environment, they have a role as predators, food for other fish, detrivors and they are an important element in the circulation of the energy and the nutrient in the aquatic ecosystem. Today, number of the european crayfish species populations is decreasing. It is caused by unfavourable regulation of streams, water pollution and the occurence of crayfish plague. The main purpose of present study was examining the impact of electrostimulation on the males of the crayfish and obtaining sex products (the sperm). The principle of this research was determining whether the male of crayfish are able to extrude spermatophore with sperm by an electric stimulus. The transformer was used as resource alternating current in experiments. All experiments conducted in a laboratory of experimental device for fish farming in Vodňany. Experiments were conducted in 2011 on a male of the spiny-cheek crayfish (Orconectes limosus), the signal crayfish (Pacifastacus leniusculus) and the red swamp crayfish (Procambarus clarkii). The results of this work and success of the experiments suggest, that electrostimulation could be used for obtaining sex products (the sperm) from crayfish males. Results from a laboratory of electron microscopy confirm the harmlessness of electrostimulation on the shape and structure of sperm. The sperm can be used to artifical insemination of the crayfish eggs in future. However, sperm capacitation is problematic.
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Comparison of Postembryonic Development of Native and Non-native Crayfish
KANTA, Jan
The diploma thesis observed the indicators of growth in individual developmental stages of our native crayfish (Astacus astacus, Austropotamobius torrentium, Astacus leptodactylus) and non-native crayfish (Pacifastacus leniusculus, Orconectes limosus) under experimental conditions. The next aim of work was to describe the time of hatching of these species, the moulting interval, the frequency of moulting and increase after individual moulting during the first vegetation season in two different temperatures (15{$\rm^o$}C a 21{$\rm^o$}C).
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