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Relationship between egg size and incubation time in geckos (Squamata: Gekkota)
Mrskočová, Jana ; Kratochvíl, Lukáš (advisor) ; Frynta, Daniel (referee)
Previous studies of the relationship between egg size and the embryonic development time showed a positive correlation between the two variables at interspecies level, thus offering the idea that the evolution of the latter could be a limiting factor for enlarging the size of eggs during evolution. Some research into interspecies and intraspecific level of reptiles doesn't confirm this correlation. At the same time, the relationship between the development time and egg size is influenced by many factors, such as shifts in ontogenetic stages of the embryo at the time of ablation of eggs, due to temperature and humidity, the presence of embryonic diapause during embryogenesis or synchronization of hatching time, of which the authors of previous studies took no account or filtered out inaccurately. I think that most of these factors can be well controlled in intraspecific studies, but, variation in egg size within species also tends to be small, which prevents a reliable test for correlation. The solution can be to compare closely related species with high variability in the size of the eggs, in our case the geckos of the genus Paroedura and family Eublepharidae. I eliminated temperature effects by comparing the time of incubation in two equal constant temperatures. The results show that, in this...
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Relationship between egg size and incubation time in geckos (Squamata: Gekkota)
Mrskočová, Jana ; Kratochvíl, Lukáš (advisor) ; Frynta, Daniel (referee)
Previous studies of the relationship between egg size and the embryonic development time showed a positive correlation between the two variables at interspecies level, thus offering the idea that the evolution of the latter could be a limiting factor for enlarging the size of eggs during evolution. Some research into interspecies and intraspecific level of reptiles doesn't confirm this correlation. At the same time, the relationship between the development time and egg size is influenced by many factors, such as shifts in ontogenetic stages of the embryo at the time of ablation of eggs, due to temperature and humidity, the presence of embryonic diapause during embryogenesis or synchronization of hatching time, of which the authors of previous studies took no account or filtered out inaccurately. I think that most of these factors can be well controlled in intraspecific studies, but, variation in egg size within species also tends to be small, which prevents a reliable test for correlation. The solution can be to compare closely related species with high variability in the size of the eggs, in our case the geckos of the genus Paroedura and family Eublepharidae. I eliminated temperature effects by comparing the time of incubation in two equal constant temperatures. The results show that, in this...
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Evolutionary ecology of the genus Geosmithia
Veselská, Tereza ; Kolařík, Miroslav (advisor) ; Gryndler, Milan (referee)
7 Abstract The genus Geosmithia Pitt (Ascomycota: Hypocreales) belongs to fungi living in symbioses with bark beetles. Its original strategy is association with phloeophagous bark beetles (Coleoptera: Scolytinae). The Geosmithia shows strong affiliation to vector (bark beetles) worldwide and the spectrum of host plants is delimitated by niche of vector. The genus includes the specialists to family Pinaceae, but also the generalists with wide range of host plants mainly belonging to broad-leaved trees. G. morbida changed its ecology from saprotrophic to pathogenic way of life and causes decline of Junglans nigra in the USA. Characteristics which allow its pathogenesis are not known. Another derived strategy, which occurred at least twice independently, is association with the ambrosia beetles. The ambrosia beetles create galleries in xylem with low nutritive value, and thus they cultivate ambrosia fungus, on which they are entirely nutritively dependent. The ambrosia fungi share convergent phenotype which leads to large terminal conidia and to ability of yeast growth. This master thesis is focusing on study of the features, which are important for individual ecological groups: the specialists to family Pinaceae, the pathogene, the ambrosia fungi and the generalists. It is becoming apparent that the most...
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Evolution of Arvicolinae: a phylogenetic approach
ROBOVSKÝ, Jan
The topic of the presented thesis is evolution of the arvicoline rodents (Cricetidae) using the phylogenetic approach. Phylogenetic relationships within the Arvicolinae were examined based on two genes (mitochondrial cytb, nuclear GHR exon 10) and approx. 470 morphological, developmental, behavioural, ecological and cytogenetic characters. The thesis consists of four related topics: (i) Phylogeny of arvicoline rodents (Robovský et al. 2008: Zool. Scr. 37: 571-590); (ii) Fossils, phylogeny and morphological evolution in the Arvicolinae (Rodentia: Cricetidae); (iii) Enamel, diet and habitat evolution in arvicoline rodents (Cricetidae); and (iv) Vole population cycles: evolutionary history or actual life histories?.
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