|
|
The Competition Among Pollinators and the Impact of Managed Bees on Wild Pollinator Populations
Voldřichová, Alžběta ; Straka, Jakub (advisor) ; Štenc, Jakub (referee)
Pollinators play an important role in ecosystems. Their ties to plants are essential for the reproduction of many plant species and thus for the protection of species diversity. Pollinator species therefore need to be protected. But to protect them effectively, it is necessary to understand the relationships between pollinators. However, the interaction between pollinators is a complex topic that needs further research. One of the current threats to pollinator populations is commercial pollinator rearing. Commercially reared species, especially Apis mellifera and Bombus terrestris, have been introduced almost all over the planet due to their positive effects on crop yields and its by-products. Moreover, in their native ranges they are bred in much higher concentrations than would be possible without human intervention. But high concentrations of commercial pollinators do affect populations of wild ones. This thesis describes forms of pollinator competition and addresses the impact of commercially reared pollinators on wild pollinator populations. KEY WORDS: Honeybee - Bumblebee - Hoverfly - Nest usurpation - Pathogen transfer - Species protection - Invasive species
|
|
|
Ecological and Evolutionary Processes Driving the Structure of Plant-Pollinator Networks
Hadrava, Jiří
Associations between flowers and pollinators are responsible for reproduction of majority of plant species as well as food supply for substantial part of animal diversity on the Earth. Until recently, the studies on plant-pollinator relationship were focused predominantly on pollination of particular plant species, with only little or no accent on community perspective. In recent decades, however, pollination ecology shifted its focus rather to community context by introducing so called pollination networks. This approach allows us to view the ubiquity and complexity of the interactions between plants and their pollinators and it opened up many new opportunities to study the pollination from animal perspective or to access spatio-temporal variability in the interactions. However, we still have only limited insight into the processes driving the structure and dynamics of such networks. The assembly of plants, pollinators and their interactions are driven by various ecological as well as evolutionary processes. From the ecological point of view, species co-occurrence in time and space may affect the interactions, or species flexibility for various community contexts providing different food sources may play role. In the evolutionary perspective, species may have various co-adaptations due to their...
|
|
|
Ecological and Evolutionary Processes Driving the Structure of Plant-Pollinator Networks
Hadrava, Jiří ; Klečka, Jan (advisor) ; Gilbert, Francis Sylvest (referee) ; Vujić, Ante (referee)
Associations between flowers and pollinators are responsible for reproduction of majority of plant species as well as food supply for substantial part of animal diversity on the Earth. Until recently, the studies on plant-pollinator relationship were focused predominantly on pollination of particular plant species, with only little or no accent on community perspective. In recent decades, however, pollination ecology shifted its focus rather to community context by introducing so called pollination networks. This approach allows us to view the ubiquity and complexity of the interactions between plants and their pollinators and it opened up many new opportunities to study the pollination from animal perspective or to access spatio-temporal variability in the interactions. However, we still have only limited insight into the processes driving the structure and dynamics of such networks. The assembly of plants, pollinators and their interactions are driven by various ecological as well as evolutionary processes. From the ecological point of view, species co-occurrence in time and space may affect the interactions, or species flexibility for various community contexts providing different food sources may play role. In the evolutionary perspective, species may have various co-adaptations due to their...
|
|
|
Effect of pollination on seedset and yield of buckwheat (\kur{Fagopyrum esculentum}).
NOLČ, Radek
Common buckwheat is a attracting plant for many pollinators, therefore it be helping to restore biodiversity in the landscape. The most important of pollinators of buc kwheat are honeybee and hoverflies. The aim of this thesis was to find out effect of pollination of buckwheat sown with honeybees and the others pollinators on the seed set and yield of archenes in different varieties of buckwheat. A small-plot field experiment was established with three varieties of common buckwheat in the Pilsen Region, in the place of Zábělá. Before flowering began, half of the plots were covered with insect screens. The buckwheat stand was evaluated from the point of: plants height, number of branches, number of flowers and inflorescences on a plant, nectar volume in Thrum flowers, flowering time, number of archenes on a plant, the weight of thousand of archenes and the yield of archenes. Monitoring of pollinators was performed at the time of buckwheat flowering at 9, 10, 11, 12 and 14 hours, during 10 minutes, using photos. Nectar collection took place on five consecu tive days, from 16. 7. until 20. 7., at 9, 10 and 11 hours. Total of 31 insect species were recorded on buckwheat flowers. The most common effective pollinators of buckwheat were honeybees, (39,7 %) and hoverflies (37,5 %). The significant difference in nectar production was found among the tested buckwheat varieties. The yield of achenes on covered plants was 87 % lower than on freely accessible plants.
|
|
|
Mimicry in hoverflies
Daňková, Klára ; Hadrava, Jiří (advisor) ; Raška, Jan (referee)
Batesian mimicry, the imitation of harmful species manifested by harmless ones, could bring a lower risk of predation to the mimetic species. Therefore, it occurs in many different taxa. Hoverflies (Diptera: Syrphidae) could stand for one of the most various mimics. This worldwide-distributed family is known for taking shape of many Aculeata species using plenty of different adaptation connected with colouration, morphology and even behaviour. The aim of this work is to review the diversity of mimicry in Syrphidae, highlight the main selection pressures and to put forward a potential field of future research. Hoverflies are being studied for the last two hundred years. However, just several study approaches are dominating the field. In order to open a new chapter of their research, I bring a wider synthesis of knowledge related to the ecological and evolutionary context of this phenomenon.
|
|
|
Mimicry in hoverflies
Daňková, Klára ; Hadrava, Jiří (advisor) ; Raška, Jan (referee)
Batesian mimicry, the imitation of harmful species manifested by harmless ones, could bring a lower risk of predation to the mimetic species. Therefore, it occurs in many different taxa. Hoverflies (Diptera: Syrphidae) could stand for one of the most various mimics. This worldwide-distributed family is known for taking shape of many Aculeata species using plenty of different adaptation connected with colouration, morphology and even behaviour. The aim of this work is to review the diversity of mimicry in Syrphidae, highlight the main selection pressures and to put forward a potential field of future research. Hoverflies are being studied for the last two hundred years. However, just several study approaches are dominating the field. In order to open a new chapter of their research, I bring a wider synthesis of knowledge related to the ecological and evolutionary context of this phenomenon.
|
|
|
Reproduction of \kur{Achillea millefolium} agg. and \kur{Achillea ptarmica} in meadows and verges
TOMŠOVÁ, Pavla
Several changes in land use during the last 50 years of 20th century had a significant impact on the composition of traditional meadows. The abundance of many plant species typical for traditionally managed meadows has declined. But some of these species have found a refuge in habitats such as field margins and road verges. The aim of this study was to describe how the reproduction success of two related Achillea species A. millefolium agg. and A. ptarmica depends on (i) the particular habitat in which they grow (meadow/verge); (ii) the abundance of pollinators in the study site; and (iii) timing of flowering within the season. Moreover, the longevity of individual flowers of the two taxa has been studied in order assess the width of the time frame the reproduction takes place in. These objectives were achieved by means of measuring plant total seed production and germination as proxies of reproductive success both in meadow and verge populations at the beginning, peak and end of the flowering season of the two species in 2012. The plants were chosen at plots, where concurrently a pollinator survey has been conducted as the part of the broader project. The durations of the male and female phases of individual flowers have been studied in separate experiments.
|
guest ::
