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Social nest structure of sweat bee Lasioglossum marginatum (Anthophila: Halictidae)
Vinická, Eliška ; Straka, Jakub (advisor) ; Bogusch, Petr (referee)
Family Halictidae is one of the most socially diverse taxa of bees, and especially one of the genera that belongs in this family. It is the genus Lasioglossum, which includes different types of sociality from solitary behavior to eusociality. Among the species of this genus, one stands out and that is the species Lasioglossum marginatum. Its social behaviour was described in the years 1959-1972 by Plateux-Quén in France. Its sociality is eusocial and is completely unique. In its nests there are dozens to hundrets of individuals, all of which are produced by a single queen. The life cycle of this species is not one-year, as in most species, but is spread over 5(6) years and the queen survives the entire time. It is a univoltine species and therefore produces only one generation of offspring per year. This is not unusual, except that eusocial species in this family are always at least bivoltine with a one-year social cycle. In each year of the five-year cycle, the queen produces only workers. Only in the last year of the cycle are future foudresses and males produced. The purpose of this work is to confirm or disprove Plateux-Quénu's statements. Field experiments were performed from 2020 to 2023 in the Kletnice nature reserve in South Moravia. A total of 354 nests were excavated, and their nest...
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Causes of bee loss (Anthophila) in the landscape
Bureš, Vít ; Straka, Jakub (advisor) ; Tropek, Robert (referee)
Bees (Anthophila) are one of the most important pollinators in the majority of Earth's biotopes. They interact with almost one-fifth of flowering plants and together with other pollinators they secure one- third of human food sources. Since the end of World war II,along-term decrease in numbers of bees and other insects is observed due to degradation of natural habitats, expansion of agriculture, pesticide usage, parasites, and infections. In North America and Europe, several studies reported a significant loss of bee diversity and abundance. The situation in tropics is unclear and there is not enough evidence if bees are threatened there. Specific changes in relation to the decrease of the bee population are observed in the case of honey bee (Apis mellifera). Due to human beekeeping activities and specific honey bee attributes such as bigger body size or tolerance to lower temperature, honey bees show different trends in their abundance than other bees. This study discusses the causes of these losses and possible future consequences, for example, the collapse of ecosystems as a result of pollination crisis or lack of human food. On the other hand, several phenomena such as extensive agriculture, green cities, or wildfires have a positive impact on bee abundance and diversity. This thesis presents...
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Population genetics and speciation in Stylops (Strepsiptera)
Kodejš, Karel ; Straka, Jakub (advisor) ; Černá, Kateřina (referee)
This thesis is focused to population genetics of selected species of genus Stylops in Europe. Within this genus, five species was analysed by usage of two approaches - microsatellite analysis in Stylops ater and analysis of mitochondrial DNA in all five species. Mitochondrial gene for cytochome c oxidase (1st subunit) was used. For microsatellite analysis was performed bayesian clustering analysis and ABC approach (Aproximate Bayesian Computation). Mitochondrial markers were processed by making haplotype networks and demography analysis by computing Bayesian skyline plots. For Stylops ater, surprisingly low lewel of population subdivision was detected, yet with clearly differentiated population clusters from Scandinavia and baltic coast of Europe, which may imply period of isolation of these populations or relativelly recent population expansion and genetic differentiation due to lower population sizes. Next, hypotesis of possible temporal segregation of subpopulations of Stylops nevinsoni based on different aktivity period of their host species groups, was supported. In other three species, population subdivision was observed to be related either due to host specialisation (Stylops mellitae) or geographic consequences (S.nassonowi, S.spreta). Interesting finding is also detection of population...
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