Search for dissertations about: "Bumblebees"
Showing result 6 - 10 of 22 swedish dissertations containing the word Bumblebees.
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6. Effects of landscape context on populations of bumblebees
Abstract : To investigate recent declines in bumblebee populations, I carried out landscape analyses, made field studies of bumblebees, flowering plants and pollination in an agricultural region in southernmost Sweden. Studies were carried out in landscapes of contrasting agricultural intensity and land-cover configuration; "simple" landscapes highly dominated by large crop fields, and "complex" with mixed farming, grasslands and smaller fields. READ MORE
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7. Go with the flow : visually mediated flight control in bumblebees
Abstract : Despite their small brains and tiny eyes, flying insects are capable of detecting and avoiding collisions with moving obstacles, and with remarkable precision they navigate through environments of different complexity. For this thesis, I have investigated how bumblebees use the pattern of apparent image motion that is generated in their eyes as they move through the world (known as optic flow), in order to control flight. READ MORE
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8. Movements in the dark : flying, landing and walking in insects
Abstract : Flying, as well as walking insects rely on vision to regulate locomotion, even in the dark when the visual system is much less reliable. To manage visual control of these behaviours at low light intensities, many insects have evolved optical adaptations, such as larger facet lenses and wider rhabdoms, and neural adaptations, such as spatial and temporal summation, to increase their visual sensitivity. READ MORE
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9. Effects of Farming Practice on Pollinators and Pollination across Space and Time
Abstract : Several studies have found that organic farms support higher biodiversity, but results vary between studies such that some also show no or even negative effects. There can be many reasons why studies comparing organic and conventional farming show conflicting results. READ MORE
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10. Bee foraging and pollination : Consequences of spatial and temporal variation in flower resources
Abstract : Wild bees foraging in contemporary agricultural landscapes are, because of agricultural intensification, faced with the challenges of reduced flower-rich habitats, as well as a changed spatio-temporal distribution of flower resources. As a result of this and other stressors such as pesticide exposure, widespread declines of bees have been reported. READ MORE