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The parasitoid community of two microlepidopteran species living on hops
Hovorka, Tomáš ; Janšta, Petr (advisor) ; Libra, Martin (referee)
Interactions between parasitoids, phytophagous insects and their host plants play one of the crucial role in the trophic relationships of terrestrial food webs. According to current knowledge, more than half of all known terrestrial species are part of this food web (parasitoids- herbivores-plants). In many species of herbivore hosts, interactions with parasitoids have led to the evolution and diversification of different defense strategies. An example of a primary defense strategy against predators and parasitoids is the formation of shelters such as leaf mines, leaf cocoons or galls. These strategies are a key factor influencing the composition of the parasitoid community. In this thesis, the complex of parasitoids in two microlepidopteran species with different life strategies living on hops (Humulus lupulus) was investigated. The caterpillars of Caloptilia fidella (Lepidoptera: Gracillaridae) first mine within leaves of hops, later, when they start to feed exophagously, they create leaf rolls and cocoons on the outer surface of the leaf. Caterpillars of the species Cosmopterix zieglerella (Lepidoptera: Cosmopterigidae) remain in the mine throughout their larval development. The obtained parasitoids were identified both based on morphology and with the help of two gene fragments, namely CO1 and...
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The Effect of Presence and Abundance of Parasites (Nomada, Stylops) on the Host Species Population (Hymenoptera: Andrena) at the Level of Entire Communities
Bureš, Vít ; Straka, Jakub (advisor) ; Libra, Martin (referee)
Bees (Anthophila) play a crucial role as pollinators, vital for maintaining biodiversity in ecosystems. However, the decline in pollinator populations in recent years raises concerns about ecosystem stability. This study investigates the impact of parasitism on host bee populations of the genus Andrena as a potential factor influencing the decline of insects. Additionally, it examines populations of parasites of the genera Stylops and Nomada as indicators of host population status. Bees of the genus Andrena are abundant in the western Palearctic and are commonly parasited by Stylops and Nomada. Leveraging a large dataset from Europe, this study uses abundance data to explore the influence of abiotic and biotic factors on the parasitization rates of host Andrena bees. Specifically, the effects of abiotic factors such as altitude, habitat type, annual rainfall, and average temperature on the parasitization rates by both parasite types has not been confirmed. The results indicate that within small geographical units (sites), larger populations of host Andrena bees are more heavily parasitized by Stylops compared to smaller populations, while this trend does not hold true for Nomada. Interestingly, this study reveals that Stylops and Nomada coexist within the same host populations without competing for...
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Community structure of caterpillar parasitoids from tropical rain forest
LIBRA, Martin
The aim of this dissertation is to investigate the community structure of parasitoids and their interactions with their hosts - caterpillars in the rainforest of Papua New Guinea, focusing on beta diversity and altitudinal trends. We show that parasitoid beta diversity is higher than the beta diversity of their hosts, which was also projected in their interactions. The altitude plays important role in the diversity of parasitoids, where we show that Ichneumonidae are more diverse at high elevation than at low elevation, which was not observed for other large insect families. Further, we performed a manipulative experiment, exposing live caterpillars in different elevations of tropical rainforest. Caterpillars faced similar mortality from parasitoids between elevations, but higher mortality from predation at low elevation. In the last chapter, we point out how important is correct species identification because wrong identification can misinterpret observed interactions.
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Usage of the photovoltaics in the cars operation
Furmanová, Rea ; Libra, Martin (advisor) ; Blahovec, Jiří (referee)
The theoretical part is focused to main topic of my final thesis (photovoltaics, hydrogen and fuel cell vehicle). In first part photovoltaics is described different kinds of solar panel and their connections. In second part is solved production, storage, distribution of hydrogen and also fuel cell type PEMFC, which is specified into mobile vehicles. Last theoretical part sis devoted to cars with fuel cell, history of these cars and current market with them. The own measurement is concentrated to testing of hydrogen radio control model and evaluating of results gained from FVE Hrádek.
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