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Impact of endosymbiotic bacteria on the capacity of host spiders (Araneae) to provide ecosystem services
Gloríková, Nela ; Řezáč, Milan (advisor) ; Tropek, Robert (referee)
The impact of the microbial community as well as individual strains of endosymbiotic bacteria on spider hosts has only begun to be increasingly studied in the last 20 years. This is primarily due to new molecular methods and devices, but on the other hand also to a growing desire to unravel the mechanisms behind the ability of spiders to provide ecosystem services. Their unique contribution lies in their high diversity, their generalist hunting strategy, and their efficient long-distance dispersal called ballooning. However, their abilities are possibly affected by the tiny organisms inhabiting their tissues - from the haemolymph to the digestive tract and the reproductive organs. In this work, attention is paid to the aspects that are influenced or manipulated by microbes for the purpose of their own transmission. Studies investigating known reproductive manipulators such as Wobachia, Cardinium or Rickettsia are summarized. The work summarizes recent findings in the areas of the impact of endosymbiotic bacteria on metabolic pathways and nutritional support, but also on behavioral aspects such as predatory/antipredatory behavior, defense against parasitoids or pathogens, and dispersal or avoidance of stress. Information about spiders is also related to knowledge about other invertebrates. Keywords:...
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Comparison of reproductive parameters of Central European populations of the critically endangered Hermit butterfly (Chazara briseis)
Štochlová, Tereza ; Sedláček, Ondřej (advisor) ; Kadlec, Tomáš (referee)
The Hermit butterfly Chazara briseis is a species from the family Nymphalidae, inhabiting mostly short-stemmed dry steppes. In Central Europe, it is critically endangered. It is therefore currently the subject of many conservation activities, including reintroductions. In such translocations of individuals, it is important that the native and source populations be as closely related as possible in all respects. Therefore, individuals of two forms of this species, Ch. briseis pannonica (Austrian population) and Ch. briseis bataia (Czech population) were bred and their reproductive characteristics were recorded and the differences between the two forms were observed. During two seasons 5 Austrian and 8 Czech females were successfully bred. The Austrian and Czech populations differed mainly in the timing of adult hatching and the beginning of the laying of eggs by females - Austrian individuals are phenologically shifted to one week to 14 days earlier. Individual populations of the same species may also differ from each other in the presence of Wolbachia pipientis. This bacterium can affect the sex ratio in a population as well as the reproduction behavior of individuals. There was a suspicion of its presence in the Czech population. Therefore, a part of the Czech population was treated with...
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