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Life history strategies of arbuscular mycorrhizal fungi
Fričová, Renata ; Janoušková, Martina (advisor) ; Kohout, Petr (referee)
Arbuscular mycorrhiza is a symbiotic interaction of vascular plants and arbuscular mycorrhizal (AM) fungi from subphylum Glomeromycotina. Currently, it is difficult to predict the population dynamics of AM fungal communities, mainly because little is known about their life-history strategies. However, it is clear that AM fungi differ in a range of traits. Physiological and ecological differences between AM fungi can affect the outcome of their competition as well as cooperation with the plant symbiont and the successional dynamics of the whole community. In order to advance our knowledge of AM fungal life-history strategies, it is crucial to deepen our understanding of the traits and factors that modify interactions between the symbionts. This bachelor thesis is designed as a literature survey aimed at summarizing knowledge about functional traits of AM fungi and the impact of these traits on their life-history strategies. Key words: arbuscular mycorrhizal fungi, life-history strategies, host plant, traits, mycelium, colonization, competition, community, succession
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Behaviour of avian predators to seed bugs (Lygaeoidea): effectiveness of chemical defence
Chalušová, Kateřina ; Exnerová, Alice (advisor) ; Sedláček, Ondřej (referee)
By warning signalling prey advertises its unpalatability to the predators. Typical examples are true bugs (Heteroptera) combining optical and chemical signals. The aim of this study was to find out the effectiveness of chemical defence against wild-caught adults of great tits (Parus major) and blue tits (Cyanistes caeruleus) and towards hand-reared juveniles of great tits. The tested prey were adults and larvae of two invasive species of genus Oxycarenus (Heteroptera: Oxycarenidae) (aposematic O. lavaterae, non-aposematic O. hyalinipennis), adults of Horvathiolus superbus (Heteroptera: Lygaeidae) and crickets (Gryllus assimilis) as a control prey. We were focusing on the influence of seed bugs to the initial reaction, the learning process and to the displays of discomfort behaviour in tits. Reactions affected by the tit species, age and sex were compared in adults. Juveniles were divided into two independent experimental groups, one group was offered adults of genus Oxycarenus, the second was offered sunflower (Helianthus sp.) or Digitalis sp. seed fed adults of H. superbus. The first bug offered did not elicit an initial aversive reaction in tits, but birds reacted aversively to the bugs after having further handling experience. All juveniles, contrary to the adult tits, attacked at least one bug...
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Substrate specifity of epiphytic communities of diatoms (Bacillariophyceae) and desmids (Desmidiales)
Mutinová, Petra ; Neustupa, Jiří (advisor) ; Šímová, Irena (referee)
Substrate specificity of epiphytic communities of diatoms (Bacillariophyceae) and desmids (Desmidiales) Bc. Petra Mutinová Master's thesis, Prague, 2015 Abstract It has been always assumed, and frequently reported, that host plants, as biologically active substrates, should have a direct influence on associated epiphyton. However, some studies favoured the neutral substrate hypothesis. Thus the relationship between host plant and epiphytic community remained unresolved. This Master's thesis focused on the basal question that numerous previous studies overlooked. Is there any significant influence of host plant on freshwater algal epiphyton in comparison to the influence of other factors, e.g. site and environmental conditions? In addition, substrate specificity of individual algal taxa was investigated. The research concerned several types of natural plant substrates at several water bodies in the Czech Republic, which provided a more accurate and general insight in the ecology of microphytobenthos. The results have demonstrated that site was the main factor affecting epiphytic community structure, followed by mild, but still noticeable, effect of environmental conditions (pH and conductivity). In contrary, host plant had almost no influence and very few algal species were found to be host specific....
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