National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Hormonal control of sexually dimorphic traits in lizards
Schořálková, Tereza ; Kratochvíl, Lukáš (advisor) ; Reichard, Martin (referee) ; Frynta, Daniel (referee)
This Ph.D. thesis is fosuced on hormonal control of sexual dimorphism in lizards and is composed of four contributions. Sex steroid hormones are important for development and regulation of sexual dimorphism in reptiles, but particular traits are controlled by different endogenous mechanisms. Male sexual behaviour of the gecko E. macularius is controlled by testosterone and can be successfully induced in females, only the onset and cessation of the behaviour take longer than in males. The onset and cessation of particular traits are not immediate for both sexes, and this time component has to be taken into account in future experiments using hormonal manipulations. In other species of the gecko, P. picta, testosterone and dihydrotestosterone stimulates the expression of male sexual behaviour in females as well. Male offensive aggression occurs only in testosterone-treated females, probably due to its conversion to biologically active estradiol in the brain, testosterone thus stimulates offensive behaviour probably only indirectly. Both androgens also stimulate the growth of the male copulatory organs, hemipenes, in females, but in different way than the size of penis in male mammals. Sexual behaviour of both gecko species is associated with sex recognition, which is allowed by androgen-triggered cues in...
Cognitive and aggressive behaviours in the annual killifish, Nothobranchius orthonotus
Kubická, Lucie ; Reichard, Martin (advisor) ; Horký, Pavel (referee)
I used annual killifish Nothobranchius orthonotus to investigate two separate questions related to behavioural aspects of their life history. The first study focused on spatial cognitive ability of two N. orthonotus populations that originated from temporary pools that varied in their expected duration due to differences in annual precipitation patterns (dry and humid region). Test of cognition was based on the ability to learn to find food in a dichotomous test. It was assumed that learning ability differs between populations when tested in young and old age along with their difference in captive lifespan. Additionally, association between cognitive ability and other life history traits was tested. It was found that: (1) there was no difference in the ability to learn spatial task between populations; (2) both populations had similar lifespan with no cognitive decay in older age, and older fish from dry region population had committed even less errors in the learning task than they did as young fish; (3) fish were able to effectively learn the task but (4) solitary fish had lower learning ability than group-reared fish; (5) longer- living fish were quicker learners; (6) high resting metabolic rate was associated with more effective learning; (7) hesitant fish found the food reward in learning task...
Age structure and growth of wild brown trout in relation to population density and habitat quality
Závorka, Libor ; Slavík, Ondřej (advisor) ; Matěna, Josef (referee) ; Reichard, Martin (referee)
Brown trout Salmo trutta L. is a fish species with high socio-economic value, which is favourable among anglers and a successful invader worldwide. The aim of this thesis is to explore environmental factors affecting body growth and survival of brown trout with emphasis on density dependent selection in juvenile life stages. This thesis is specifically focused on: (1) effect of population density on growth and survival with respect to a dynamic of a local group of individuals (papers I and II); (2) effect of inter-individual differences in behaviour on the relationship between individuals life-history traits and available resources (papers III and IV); (3) link between demo-genetic structure of population and growth and mortality rates of individuals (papers V, VI and VII). Datasets for this thesis were collected during a long-term mark-recapture study on wild brown trout population (2005-2011) in the catchment of the Otava River in Šumava National Park (Czech Republic) and a set of field and laboratory studies conducted on wild populations in streams on west coast of Sweden. In accordance with some previous studies, this thesis showed that growth of juvenile brown trout is negatively affected by population density. Nonetheless, this thesis reveals that the negative effect of density dependent...
Phylogeny and biogeography of Neotropical and African riverine cichlids: multilocus phylogenetic methods in the evolutionary studies
Musilová, Zuzana ; Novák, Jindřich (advisor) ; Bryja, Josef (referee) ; Reichard, Martin (referee)
Summary: The thesis comprises from the introduction and five main parts: three of them are published papers, the rest two are manuscripts prepared for submitting to the scientific journals. The first two are published phylogenetic studies of the cichlasomatine cichlids based on (1) molecular characters, and (2) both morphological and molecular data with the description of a new genus Andinoacara. The third (3) is the already published description of the new species Andinoacara stalsbergi from Peru combining both morphological and phylogenetic approaches and including the detailed phylogeny of the genus Andinoacara. The next unpublished manuscript (4) is the more detailed comprehensive phylogeography of the two non-relative genera (including Andinoacaras) of the trans-Andean cichlids. Including all valid species from the majority of their distribution areas it was reconstructed the ancestral area of both genera in the Choco region, Colombia, and revealed the directions of their distribution spreading. The last (5) unpublished manuscript is the phylogeographical study of the cichlid genus Serranochromis from the headwaters of the totally unknown Central Angola. It showed several evidences of the faunal exchange among the adjacent river systems. Lastly, the thesis is supplemented by several appendices...
Out of Asia Minor into Danube Drainage: Phylogeography and colonisation pathways in the loach fish Cobitis strumicae
Majtánová, Zuzana ; Choleva, Lukáš (advisor) ; Reichard, Martin (referee)
The spiny loach Cobitis strumicae is a small bottom-dwelling freshwater fish whose progenitor colonised the Balkan Peninsula from the Near East through the Asia Minor. The current geographic distribution of C. strumicae forms a ring around the Stara Planina (Balkan mountains), inhabitting Danube Basin and coastal rivers of Black Sea and Aegean Sea. Using one marker of mitochondrial DNA (gene for cytochrom b) and one marker of nuclear DNA (S7 gene, first intron), we reconstructed the species distribution and phylogenetic relationship of 44 populations throughout C. strumicae distribution. We also analysed its sister species, C. punctilineata, which lives inside the distribution area of C. strumicae. Aplication of four phylogenetic approaches confirm the monophyly and species statut and endemicity of C. punctilineata, and, moreover, the evidence of secondary hybridization with C. strumicae was found. The network analysis using median-joining method showed deep divergence between the both species. Phylogenetic analyses for cyt b gene confirmed the monophyly of C. strumicae, with internal substructure into at least two well divided lineages, which suggests the process of local speciation. Phylogenetic analyses of S7 gene did not support the monophyly of C. strumicae. Instead, the two separated...
Monitoring of fish fry as an indicator of river habitat quality
Jurajda, Pavel ; Slavík, O. ; Reichard, Martin ; Ondračková, Markéta
The aim of the study was to analyse the 0+ juvenile fish community at designated river localities selected according to the state network of the water quality control.

National Repository of Grey Literature : 11 records found   1 - 10next  jump to record:
See also: similar author names
1 Reichard, M.
Interested in being notified about new results for this query?
Subscribe to the RSS feed.