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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

A Comparison of Antlions, Bees, Darkling Beetles and Velvet Ants Across Sand Dune and Non-Sand Dune Habitats at Ash Meadows National Wildlife Refuge

Boehme, Nicole F. 01 May 2014 (has links)
Insects fulfill important roles within all ecosystems, including deserts, and interact directly and indirectly with the endemic and endangered species at the Ash Meadows National Wildlife Refuge (AMNWR). Here I investigate the variability of species richness, diversity, abundance and community composition of four insect groups between stabilized sand dune habitats, unstabilized sand dune habitats and non-sand dune habitats. The insects examined in this thesis include antlions (Myrmeleontidae), bees (Apiformes), darkling beetles (Tenebrionidae) and velvet ants (Mutillidae). As the impact and interactions of two of the insect groups, antlions and velvet ants, are largely unknown within any ecosystem, this thesis also includes a faunal study of velvet ants at AMNWR and their spatial and temporal variation at the refuge. Generalized linear mixed models were used to identify significant differences in richness, diversity and abundance for each insect group between the stabilized sand dune, unstabilized sand dune and non-sand dune habitats. Species richness differed between habitats for antlions, beetles and velvet ants over the study period. Diversity differed between habitats for antlions and beetles, and abundance differed between habitats for all groups over the study period. Nearly every habitat supported some unique species. The faunal survey of velvet ants revealed minor variation in flight times between species and a unique pattern of temporal niche partitioning in one species. Habitat preferences were observed for seven of 42 velvet ant species at AMNWR. In a comparison of the diversity of velvet ants between AMNWR and the Nevada Test Site (NTS), six velvet ant species that occurred at the NTS were not found at AMNWR. Diagnoses and a key are provided for the velvet ants of AMNWR. This thesis increases the number of known terrestrial invertebrates at the refuge and provides a comparison of terrestrial insect distribution and habitat use at AMNWR. These investigations contribute to the goals and objectives of the U. S. Fish and Wildlife Service to obtain basic inventories and understand the terrestrial habitat use of invertebrates at AMNWR.
352

The decline and conservation status of North American bumble bees

Koch, Jonathan B. 01 August 2011 (has links)
Several reports of North American bumble bee (Bombus Latreille) decline have been documented across the continent, but no study has fully assessed the geographic scope of decline. In this study I discuss the importance of Natural History Collections (NHC) in estimating historic bumble bee distributions and abundances, as well as in informing current surveys. To estimate changes in distribution and relative abundance I compare historic data assembled from a >73,000 specimen database with a contemporary 3-year survey of North American bumble bees across 382 locations in the contiguous U.S.A. Based on my results, four historically abundant bumble bees, B. affinis, B. occidentalis, B. pensylvanicus and B. terricola, have declined by 72 - 96% relative abundance across their native distribution, while B. bifarius, B. bimaculatus, B. impatiens, and B. vosnesenskii appear to be relatively stable. Finally, I provide some notes on the distribution, abundance, and frequency of Nosema bombi infections in Alaskan B. occidentalis.
353

Artificial alimentation of bees using natural juices during the dry season

Bernal Acosta, Ramiro 01 January 1999 (has links) (PDF)
In the community of Tunshi San Nicols of the Licto parish in the Province of Chimborazo, an evaluation was done on the effect of an energetic supplementary feeding of bees (Italian-mestizas) during the dry season (September 23 to February 20). These supplements consisted of carrot juice (T1), orange juice (T2) and sugar cane juice (T3). These supplements were also compared to a control group (T0). The experimental units consisted of 16 standard beehives distributed randomly with the 4 treatments and 4 repetitions of each treatment. The results showed that sugar cane juice (T3) obtained the best results in the consumption of the supplementary feeding because it was the only treatment where its consumption increased as the nectar sources in the zone decreased. At the end of the evaluation, 17,312.50 ml. of sugar cane juice were consumed. On the other hand, only 1,486.25 ml. of carrot juice were consumed, which was the least amount out of all of the treatments. Similarly, sugar cane juice presented the least weight loss, with 1.050 kg. per beehive. In addition, sugar cane juice also presented the greatest number of breeding frames (6.950 frames per beehive), as well as the best benefit/cost index (1.15) at the end of the study.
354

An Assessment of Non-Apis Bees as Fruit and Vegetable Crop Pollinators in Southwest Virginia

Adamson, Nancy Lee 22 March 2011 (has links)
Declines in pollinators around the globe, notably the loss of honey bees (Apis mellifera L.) to Colony Collapse Disorder, coupled with a dearth of quantitative data on non-Apis bee pollinators, led to this dissertation research, which documents the role of non-Apis bees in crop pollination in southwest Virginia. Major findings of this first study of its kind in the region were that non-Apis bees provided the majority of pollination—measured by visitation—for several economically important entomophilous crops (apple, blueberry, caneberry, and cucurbits); diverse bee populations may be helping to stabilize pollination service (105 species on crop flowers); landscape factors were better predictors of non-Apis crop pollination service than farm management factors or overall bee diversity; and non-Apis bees in the genera Andrena, Bombus, and Osmia were as constant as honey bees when foraging on apple. Non-Apis, primarily native, bees made up between 68% (in caneberries) and 83% (in cucurbits) of bees observed visiting crop flowers. While 37–59 species visited crop flowers, there was low correspondence between bee communities across or within crop systems ("within crop" Jaccard similarity indices for richness ranged from 0.12–0.28). Bee community diversity on crop flowers may help stabilize pollination service if one or more species declines temporally or spatially. A few species were especially important in each crop: Andrena barbara in apple; Andrena carlini and A. vicina in blueberry; Lasioglossum leucozonium in caneberry; and Peponapis pruinosa and Bombus impatiens in cucurbits. Eight species collected were Virginia state records. In models testing effects of farm management and landscape on non-Apis crop pollination service, percent deciduous forest was positively correlated in apple, blueberry, and squash, but at different scales. For apple and blueberry, pollination service declined with an increase in utilized alternative forage but was positively related to habitat heterogeneity. For squash, percent native plants also related positively, possibly due to increased presence of bumble bees in late summer. Species collected from both bowl traps and flowers was as low as 22% and overall site bee diversity had no effect on crop pollination service, highlighting the value in pollination research of monitoring bees on flowers. / Ph. D.
355

The impact of the natural honeycomb management on Apis mellifera colonies

Freda, Fabrizio 31 October 2023 (has links)
The mite ectoparasite Varroa destructor, poses a serious threat for the survival of the Apis mellifera colonies. The intensive use of acaricidal products is one of the most common methods for defending bees from Varroa that can cause the contamination of the wax foundation used in beekeeping. The natural honeycomb management could provide a solution for this problem, because it involves the use of frames without wax foundation which allows the bees to build a complete comb ex novo. On the other hand, colonies which are free to build cells of their choice, usually build a number of drone cells higher than colonies managed with the wax foundation. This could potentially lead to several negative consequences because the V. destructor reproductive success is greater on drone broods than on worker broods. The aim of the present study was to examine the colony development, to evaluate the honey production and to monitor the growth of V. destructor infestations and associated virus infections in Apis mellifera colonies managed by using natural honeycombs compared with the conventional management. Several colony parameters were measured in spring and summer. The strength of the colony was used to estimate the worker and drone populations. In order to measure the V. destructor infestations were used several methods, such as the natural mite fall, the powdered sugar roll, the soapy water and the brood cell uncapping. Molecular analysis was performed in order to measure the viral load of five Apis mellifera viruses. The honey produced was measured by collecting the honey stored in the supers, which are boxes placed on a beehive for bees to store. The results showed that the higher presence of drone brood in the colonies managed using the natural honeycomb did not negatively affect the colony development nor the mite V. destructor population compared to control colonies. The molecular analysis showed that the DWV was the most common virus found in bee samples, and its viral load was more influenced from the mite infestation rate than from the treatment. The analysis carried out in this study showed that the natural honeycomb management can represent a valid alternative to the wax foundation. This kind of colony management thus appears to contradict our primary hypothesis which was that letting the bees build their own honeycomb would have led to a significant increase in the V. destructor infestation. Productivity data did not provide reliable results about the difference between the natural honeycomb and the conventional colony management due to climatic adversities. Further studies will be performed to better investigate this aspect. Data about the natural mite fall and the estimation of the mite population in the phoretic/reproductive phases provided a useful starting point for further studies on the correct timing to carry out acaricide treatments both in conventional and natural honeycomb managed colonies.
356

The Causes and Consequences of Pollen Defence

Rivest, Sébastien 11 December 2023 (has links)
Animal pollination represents one of the key innovations of the flowering plants, and constitutes an essential ecological service in most ecosystems. While pollinators are the main drivers of flower evolution, some floral traits are puzzling when viewed only in the context of this mutualistic interaction. In particular, the pollen of plants belonging to several families has spines or compounds with toxic effects on insects. Little is known about the causes and consequences of these enigmatic floral traits. Yet, pollen defences might play an important role in pollination given that pollen is the main source of food of the principal pollinators in most ecosystems: bees. My thesis investigates why plants sometimes have seemingly defended pollen and how these putative defences affect host-plant use by bees. Given the potential role of flower-colonizing microbes in pollination, I also investigate the potential for these microorganisms to influence flower evolution. I found that pollinators are unlikely to act as potential agents of selection on the concentration of defence compounds in the pollen of Lupinus argenteus. Rather, physiological spillover or pleiotropy from tissues highly defended against herbivores might be responsible for a baseline level of defence compounds in pollen, while such compounds could also mediate the interaction between plants and pollen-colonizing microbes. However, I did not find evidence that flower-colonizing microbes drive the evolution of floral traits in an experimental study. I also found that pollen chemical and mechanical defences likely restrict pollen-host use by Osmiini, a group of solitary bees exhibiting high interspecific variability in their pollen diet. Bees tolerated the defences of their pollen hosts, but were often harmed by the pollen defences of co-occuring plants exploited by other Osmiini species. This pattern provides a striking parallel with the evolution of host-use in herbivorous insects feeding on vegetative tissues, and suggests that pollen defences might play an important role in structuring plant–bee interactions. Overall, my thesis contributes to our understanding of the causes of the presence of chemical defences in pollen and their consequences for the pollination mutualism.
357

A Survey of Neonicotinoid Residue Levels in Native Bees and Soil of the Mississippi Black Belt Prairie

Isbilir, Sena 07 August 2020 (has links)
Reports of declining insect populations suggest that more research focusing on this phenomenon is needed, especially in pollinator insects. Climate change, habitat destruction, and usage of certain pesticides have all been implicated in insect decline. Neonicotinoid pesticides are highly toxic to bees, can have drastic sub-lethal effects on behavior, and are persistent in the environment; likewise, they have been implicated as a major factor affecting bee populations. However, there are limited studies on native bees regarding their interactions with neonicotinoids, even regarding simple questions such as exposure levels. In this study, we aimed to assess concentrations of common neonicotinoids in native bees and soils from a threatened habitat in our region, the Black Belt Prairie, by using a modified QuEChERS LC/MS-MS protocol. Our results showed that specific taxa of native bees- Bombus spp., Xylocopa spp., and Mellissodes spp. (Family: Apidae)- were exposed to neonicotinoids. In contrast, no concentration of neonicotinoids was detected in our soil samples.
358

My Mother's Missing Bees

Malloy, Jaime Leigh 03 June 2015 (has links)
No description available.
359

Vacancy : Sculpture for solitary bees

Drvota, Ariana January 2024 (has links)
This is a project that focuses on building awareness for solitary bees and how we can use public sculptures/artifacts to help and to create a positive vision of the future through art, design,science and to promote bio diversity. A lot of modern techniques like 3D modeling, 3D printing, and CNC milling were used to bring this artifact to life. Public artworks are proven to have a positive effect on our mental health and create discussion, so with this project I wanted to create a public sculpture/artifact that benefits both humans and bees, make sure that people would take notice to it and start to investigate the creation, see all the life that lives around and inside it. This is a form with a function. The material used in this creation will be discarded wood and the wood will decompose with time.  Vacancy focuses on integrating nests for species, in this case solitary bees, within artistic public sculptures and artifacts. Through the creation of this sculpture/artifact, the project aims to engage and inspire the curiosity of the viewer to reflect on the ongoing crisis facing our pollinators. Furthermore, the project aims to promote biological diversity.
360

Investigation of the nutraceutical potential of monofloral Indian mustard bee pollen

Ketkar, S.S., Rathore, A.S., Lohidasan, S., Rao, L., Paradkar, Anant R, Mahadik, K.R. January 2014 (has links)
No / This study was designed to investigate the nutraceutical potential of monofloral Indian mustard bee pollen (MIMBP). MThe nutritional value of MIMBP was examined in terms of proteins, fats, carbohydrates, and energy value. Its chemical composition in terms of total polyphenol and flavonoid content was determined. MIMBP was screened for free flavonoid aglycones by developing and validating a high-performance liquid chromatography-photo diode array (HPLC-PDA) method. MIMBP was analyzed for in vitro antioxidant effect in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity. MIMBP was found to be comprised of proteins ((182.2+/-5.9) g/kg), fats ((137.7+/-6.8) g/kg) and carbohydrates ((560.6+/-17.4) g/kg), which result in its high energy value ((17 616.7+/-78.6) kJ/kg). MIMBP was found to contain polyphenols ((18 286.1+/-374.0) mg gallic acid equivalent/kg) and flavonoids ((1 223.5+/-53.1) mg quercetin equivalent/kg). The HPLC-PDA analysis revealed the presence of kaempferol ((65.4+/-0.5) mg/kg) and quercetin ((51.4+/-0.4) mg/kg) in MIMBP, which can be used as markers for determining the quality of bee pollen. The MIMBP extract showed DPPH free radical-scavenging activity with a half maximal inhibitory concentration of 54.79 mug/mL. The MIMBP was found to be a rich source of nutrients providing high caloric value, which makes it a candidate for a potential nutraceutical agent. The study also illustrated the high antioxidant content of MIMBP, especially in the principle polyphenols and flavonoids, which suggests its potential role in the prevention of free radical-implicated diseases. The DPPH-scavenging effect of MIMBP further confirmed its antioxidant potential. Additionally, we developed a simple, specific and accurate HPLC-PDA method for the identification and quantification of free flavonoid aglycones. This can be applied in future screenings of the quality of pollen collected by honeybees.

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