Global ETD Search

11	Four Aspects of Dogwood Pollination: Insect Visitation, a Novel approach to Identify Pollen, Floral Volatile Emission, and Tracking Parentage Rhoades, Paul Raymond 01 August 2010 (has links) Part 1: Visitation of potential pollinators to Cornus florida and C. kousa flowers was assessed in East Tennessee in 2008 and 2009. Data regarding insect visitation rates to multiple trees per location were gathered throughout the flowering period. Diurnal and seasonal variations in visitation were recorded. Pollen coverage was assessed on portions of captured insect exoskeletons that were most likely to contact the stigma. Eleven families in four insect orders were collected from C. florida and 26 families in five orders from C. kousa. The most important pollinators in eastern Tennessee were bees in the Andrenidae and Halictidae. The most common visitors to C. kousa flowers were scarab, cerambycid and cantharid beetles. Halictid bees were also frequent visitors to C. kousa. Part 2: Dispersion of flowering dogwood pollen in an orchard was evaluated by performing parentage analysis on open pollinated seedlings collected from a single maternal tree. Pollen source for 45 seedling trees were established using three polymorphic simple sequence repeat (SSR) loci. The expected leptokurtic distribution was not seen. Although the majority of paternal trees were within the 12 m radius of the study area, the trees most likely to donate pollen were some of the furthest away. Unusual pollen movement may be a product of lack of synchronization of flowering times between the mother tree and potential pollen donors in the area. Additionally relative proportions of certain pollinating insects (andrenid and halictid bees) may have moved pollen further than expected. Appendix 1: Pollen from 6 species in the genus Cornus was analyzed with Fourier Transform Infrared (FTIR) Spectroscopy to determine the utility of this tool to identify pollen grains to species. Although there were differences visible in the spectra, principal components analysis coupled with cluster analysis could not consistently identify pollen grains. Appendix 2: Floral volatile emissions from 6 species of Cornus were collected in a headspace chamber and analyzed with gas chromatography-mass spectrometry to determine if differences between emitted volatiles of C. florida and C. kousa explain differences in floral insect visitation. The relationship between floral volatile emission and the phylogeny of Cornus was also examined. Microsatelite Pollination Biology Cornus florida Cornus kousa native bees pollen flow Entomology Molecular Biology Plant Breeding and Genetics Zoology
12	Four Aspects of Dogwood Pollination: Insect Visitation, a Novel approach to Identify Pollen, Floral Volatile Emission, and Tracking Parentage Rhoades, Paul Raymond 01 August 2010 (has links) Part 1: Visitation of potential pollinators to Cornus florida and C. kousa flowers was assessed in East Tennessee in 2008 and 2009. Data regarding insect visitation rates to multiple trees per location were gathered throughout the flowering period. Diurnal and seasonal variations in visitation were recorded. Pollen coverage was assessed on portions of captured insect exoskeletons that were most likely to contact the stigma. Eleven families in four insect orders were collected from C. florida and 26 families in five orders from C. kousa. The most important pollinators in eastern Tennessee were bees in the Andrenidae and Halictidae. The most common visitors to C. kousa flowers were scarab, cerambycid and cantharid beetles. Halictid bees were also frequent visitors to C. kousa.Part 2: Dispersion of flowering dogwood pollen in an orchard was evaluated by performing parentage analysis on open pollinated seedlings collected from a single maternal tree. Pollen source for 45 seedling trees were established using three polymorphic simple sequence repeat (SSR) loci. The expected leptokurtic distribution was not seen. Although the majority of paternal trees were within the 12 m radius of the study area, the trees most likely to donate pollen were some of the furthest away. Unusual pollen movement may be a product of lack of synchronization of flowering times between the mother tree and potential pollen donors in the area. Additionally relative proportions of certain pollinating insects (andrenid and halictid bees) may have moved pollen further than expected.Appendix 1: Pollen from 6 species in the genus Cornus was analyzed with Fourier Transform Infrared (FTIR) Spectroscopy to determine the utility of this tool to identify pollen grains to species. Although there were differences visible in the spectra, principal components analysis coupled with cluster analysis could not consistently identify pollen grains.Appendix 2: Floral volatile emissions from 6 species of Cornus were collected in a headspace chamber and analyzed with gas chromatography-mass spectrometry to determine if differences between emitted volatiles of C. florida and C. kousa explain differences in floral insect visitation. The relationship between floral volatile emission and the phylogeny of Cornus was also examined. Microsatelite Pollination Biology Cornus florida Cornus kousa native bees pollen flow Entomology Molecular Biology Plant Breeding and Genetics Zoology
13	Foraging in disturbed areas : a study of sweat bees (Hymenoptera: Halictidae) in Oregon Broussard, Melissa 06 December 2012 (has links) Bees provide vital ecosystem services for cropping systems as well as natural landscapes. Declines in both both native bee and managed honey bee (Apis mellifera L.) populations has brought attention to the significance of their role as pollinators in managed and native ecosystems. As a result, conservation efforts have been undertaken to preserve them. While considerable attention has been given to honey bees, relatively little is known about many native bee species. Of particular interest is the family Halictidae, which can comprise the majority of observed individuals in many habitats. These, often small, bees are difficult to identify, and, as a result, relatively little is known about their preferred floral hosts. Because bee species assemblages vary significantly from region to region, it is important to have an understanding of local populations and their floral hosts. It is also important to understand factors which affect the quantity and quality of floral resources, such as anthropogenic disturbance. The Pacific Northwest is a diverse landscape, with rich agricultural and wildland environments that require pollinators in order to continue to thrive. Two studies examine the interface between these two systems, the first explores how roadside disturbance, which is prevalent across the world, impacts native pollinators across habitat types, and the second explores the diet of common native species, and how that diet changes across habitat types. In these studies, it was found that roadside disturbance was associated with reduced native bee diversity and abundance in the seasonally wet Willamette Valley of Oregon, but not in the more xeric Central Oregon. Bee abundance was positively correlated with temperature. Bee diet was more diverse in areas of scarce floral resources. In both regions, exotic plants were important floral hosts, representing nearly half of observed floral visitations. This thesis presents results of species analysis, floral richness and density correlations, and comparisons of floral resources used by different bee species. Implications and recommendations for land management are discussed. / Graduation date: 2013 native bees disturbance foraging pollinators Lasioglossum sisymbrii roadside Halictidae -- Oregon Lasioglossum -- Oregon Halictidae -- Food -- Oregon Lasioglossum -- Food -- Oregon Halictidae -- Habitat -- Oregon Lasioglossum -- Habitat -- Oregon
14	Tambins inverkan på naturligt förekommande pollinatörer Lindqvist, Camilla January 2014 (has links) Det här arbetet handlar om tambins inverkan på naturligt förekommande pollinatörer. Min frågeställning berör: tillgången på näring, hälsotillståndet och populationsnivån hos naturligt förekommande pollinatörer i förhållande till tambins närvaro. Det som framkommit av den här litteraturstudien är att introducerade tambin leder till att naturligt förekommande pollinatörer minskar i antal kring bikuporna, en del arter söker föda på andra blommor eller senare på dygnet än tidigare. Den minskade tillgången på föda som denna konkurrens innebär har en negativ inverkan på humlors kroppsstorlek och därmed deras överlevnad. Samt att tambin kan föra över patogener så som varroakvalster, nosemasjuka och deformed wing virus till humlor vilket leder till minskad livslängd och sämre fortplantning. / This study is about the impact of honeybees on native pollinators. My questions concerns: availability of food, the health and population level of native pollinators in relation to the presence of honeybees. What has emerged from this literature review is that the introduction of honeybees lead to a decline in numbers of bee and bumblebee pollinators in proximity of the hives and also alters their behaviour, some species choose to forage on other flowers, or later in the day than before honeybees where introduced. The reduced availability of food that this competition induces has a negative impact on the size of bumblebees body’s and thus their survival. What was also discovered was that honeybees can transfer pathogens such as varroa mites, the microsporidium Nosema ceranae and deformed wing virus to bumblebees, leading to reduced life expectancy and poor propagation. honey bee competition native bees bumble bee pollination ecology bee mortality Colony Collapse Disorder tambin honungsbin konkurrens bin bi humla vildbi vilda bin pollinationsekologi pollinering bidöd
15	The impact of the European honey bee (Apis mellifera) on Australian native bees Paini, Dean January 2004 (has links) The European honey bee (Apis mellifera) has been present in Australia for approximately 150 years. For the majority of that time it was assumed this species could only be of benefit to Australia‘s natural ecosystems. More recently however, researchers and conservationists have questioned this assumption. Honey bees are an introduced species and may be affecting native fauna and flora. In particular, native bees have been highlighted as an animal that may be experiencing competition from honey bees as they are of similar sizes and both species require nectar and pollen for their progeny. Most research to date has focused on indirect measures of competition between honey bees and native bees (resource overlap, visitation rates and resource harvesting). The first chapter of this thesis reviews previous research explaining that many experiments lack significant replication and indirect measures of competition cannot evaluate the impact of honey bees on native bee fecundity or survival. Chapters two and four present descriptions of nesting biology of the two native bee species studied (Hylaeus alcyoneus and an undescribed Megachile sp.). Data collected focused on native bee fecundity and included nesting season, progeny mass, number of progeny per nest, sex ratio and parasitoids. This information provided a picture of the nesting biology of these two species and assisted in determining the design of an appropriate experiment. Chapters three and five present the results of two experiments investigating the impact of honey bees on these two species of native bees in the Northern Beekeepers Nature Reserve in Western Australia. Both experiments focused on the fecundity of these native bee species in response to honey bees and also had more replication than any other previous experiment in Australia of similar design. The first experiment (Chapter three), over two seasons, investigated the impact of commercial honey bees on Hylaeus alcyoneus, a native solitary bee. The experiment was monitored every 3-4 weeks (measurement interval). However, beekeepers did not agist hives on sites simultaneously so measurement intervals were initially treated separately using ANOVA. Results showed no impact of honey bees at any measurement interval and in some cases, poor power. Data from both seasons was combined in a Wilcoxon‘s sign test and showed that honey bees had a negative impact on the number of nests completed by H. alcyoneus. The second experiment (Chapter 5) investigated the impact of feral honey bees on an undescribed Megachile species. Hive honey bees were used to simulate feral levels of honey bees in a BACI (Before/After, Control/Impact) design experiment. There was no impact detected on any fecundity variables. The sensitivity of the experiment was calculated and in three fecundity variables (male and female progeny mass and the number of progeny per nest) the experiment was sensitive enough to detect 15-30% difference between control and impact sites. The final chapter (Chapter six) makes a number of research and management recommendations in light of the research findings. Honeybee -- Australia Honeybee -- Fertility -- Australia Hylaeus -- Australia Hylaeus -- Fertility -- Australia Megachile -- Australia Megachile -- Fertility -- Australia Competition (Biology) -- Australia Honey bees Native bees Fecundity
16	Pollinator Populations in Massachusetts Cranberry, 1990 to 2009: Changes in Diversity and Abundance, Effects of Agricultural Intensification, and a Contribution to the North American Pollinator Survey. Notestine, Molly M 01 January 2010 (has links) (PDF) It is now widely accepted that over one-third of the global food supply depends upon pollinators. Risking severe ecological and economic implications, the status of the 4000 species of bees native to North America has been poorly understood due to a lack of long-term survey data. In this study, I conducted bee surveys on Massachusetts cranberry (Vaccinium macrocarpon Ait.) bogs from 2007-2009 and compared diversity and abundance data to those from historical surveys performed in 1990-1992 on the same bogs. I found that overall bee diversity declined severely in the 19-year survey period, while total bee abundance remained consistent. My data provide supporting evidence for the loss of North American bumble bees (Bombus spp.), but also provide the first evidence for declines in the U.S. in overall wild bee diversity. Maximizing the potential for agricultural landscapes to serve as quality pollinator habitat and identifying appropriate integrated pest management strategies should involve a comprehensive understanding of each species’ life history traits and conservation status. The loss of biodiversity associated with the intensification of agriculture has been well documented for several wildlife species but remains poorly understood for bees, which provide pollination to many agricultural crops. Most pollinator-dependent crops rely heavily on managed honey bees (Apis mellifera L.) for pollination. Four thousand other species of bees native to North America may provide pollination insurance in the event of honey bee losses, but without a clear understanding of how agricultural intensification affects wild bees, habitat conservation measures aimed at protecting them may be futile. In the second part of this study, I evaluated six metrics of agricultural intensification with respect to native bee diversity and abundance in Massachusetts cranberry bogs, including honey bee competition, bog management type (i.e. organic versus conventional), distance from epicenter of cranberry-growing region, toxicity of insecticide program, susceptibility of reproductive bees to insecticide, and surrounding land use. I found a clear association between reduced native bee diversity and abundance and the effects of increased agricultural intensification of the landscape. Recognition that native bee communities in North America are diminishing as a consequence of agricultural intensification may help to unify a movement toward improved conservation management. agricultural intensification native bees bumble bees cranberry species diversity relative abundance pollinator decline bee conservation Ecology and Evolutionary Biology Entomology Natural Resources and Conservation
17	Funktionelle Vielfalt von Hymenopteren entlang eines Gradienten agroforstlicher Nutzung in Indonesien / Functional diversity of Hymenoptera along a gradient of agroforestry management in Indonesia Höhn, Patrick 15 November 2007 (has links) No description available. 500 Naturwissenschaften YA 000 Agricultural Sciences Agroforestry systems Hymenoptera land-use intensity pest control predator pollination native bees wasps pumpkin functional diversity species richness species loss Indonesia seasonality tropics local diversity regional diversity complementarity resource use ecology conservation biodiversity habitat loss deforestation trap nests multidimensional scaling additive partitioning shade trees cocoa Theobroma cacao canopy understorey stratification ecosystem service landscape Sulawesi Lore Lindu National Park grassland primary forest Cucurbita moschata antagonists parasitism STORMA population dynamics 48.16

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