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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.
61

Pollinator Response to Annual Forb Plantings and Self-Pollinating Dry Bean Crops in Agroecosystems

Adams, Savannah Shay January 2021 (has links)
Intensive agricultural systems have had several ecological effects on the surrounding ecosystem, including contributing to widespread pollinator declines. In order to help supplement bee communities and potentially improve crop production, we set out to study annual forb plantings adjacent to dry bean crops to determine the pollinator response to both plantings and any potential effects on dry bean yield. We found that annual forb plantings provided continual floral resources throughout the sampling period, which can support bees and their pollination services in agroecosystems. We also found cross-pollination had no effect on dry bean yield in Carrington and a negative effect in Hettinger, which could be due to methodological issues. While we did not observe a yield increase in dry bean production, the addition of annual forb plantings in agroecosystems could help support the local bee community, and potentially encourage pollination services in other crops that do benefit from insect pollination.
62

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.
63

Bipollen under mikroskopet : Betydelsen av klassiska morfologiska metoder med dess för- och nackdelar / Bee pollen under the microscope : The significance of classical morphological methods and its pro’s and con’s

Nylander, Nylander January 2022 (has links)
The populations of wild pollinators have been declining worldwide, mainly due to habitat loss or change. Some farmers use honeybees to secure pollination of their crops, but honeybees can cause further problems effecting wild pollinators. Knowledge of foraging plants for honeybees can give a clue to the conditions of interactions and competition between honeybees and wild pollinators. The aim of this study was to identify plants visited by honeybees, and to compare classic morphological methods of identifying pollen to other modern palynological techniques. Samples of bee pollen from two hives in Västerbotten county, Sweden, was studied with light microscope. A selection of the samples were also studied in scanning electron microscope or by extraction of nucleic acid followed by PCR. All the identified pollen types originated from plants common in Sweden, for example, raspberry, rosebay willowherb, member of the genus Vaccinium and different types of clover. Due to similar morphology, many of the pollen types had more than one possible origin. Many types of pollen found in the samples remained unidentified. Regarding modern palynological techniques, one grain of bee pollen was substantial to extract enough nucleic acid to perform PCR. Positive PCR reactions were found for all but one of the seven PCR primers tested. Each primer gave positive reaction to only one color of bee pollen. One of the colors of bee pollen did not give any positive PCR reaction. The result of this study highlights the further need of reliable and available reference material in the palynological field.
64

The impacts of common urban metals on Bombus impatiens colony health and behavior

Scott, Sarah Barbara January 2022 (has links)
No description available.
65

FÖRUTSÄTTNINGAR FÖR VILDA POLLINATÖRER : JÄMFÖRELSE MELLAN EN NATURSKOG OCH EN PRODUKTIONSSKOG / Conditions for wild pollinators : a comparison between a nature forest and a production forest

Andersson, Jonatan January 2020 (has links)
Pollinering är en viktig ekosystemtjänst, där insekter är några av de viktigaste pollinatörerna. Under de senaste åren har mängden av pollinatörer minskat på grund av olika faktorer somklimatförändring och minskning av både antal habitat och mängd arealyta i habitat. Några avde habitat som är viktiga för pollinatörer finns i skogslandskapet, exempel glesare skogar,betesmarker i skogen, hyggen samt häll- och alvarmarker. Denna studie tittar närmare på två olika skogsområden belägna på Gotland. Ett område utgören produktionsskog (finns i Träkumla socken) och ett en naturskog (Ojnareskogen i Bunge socken). Naturskogen har en större totalyta av lämpliga habitat än produktionsskogen i Träkumla. Det fanns typer av habitat som var både lika och olika i och inom i respektiveområde där olika arter av pollinatörer kan gynnas. I naturskogen var den i areal största habitattypen glesare tallskog medan den minsta var sandmark. För produktionsskogen var den i areal största habitattypen hyggen och den minsta var vägkanter. En viktig faktor sompåverkar möjligheter för hur olika arter av pollinatörer gynnas eller inte är skötseln av skogsområdena. Olika skötselmetoder påverkar också på olika sätt. Studien visar vikten av att redan i planering och vidare skötsel av skogsområden ta hänsyn till och gynna pollinatörer. Förutsättningarna i en produktionsskog respektive naturskog är olika när det gäller såväl påverkan av pollinatörer som möjligheterna för habitatplanläggning.
66

The Effect of Flower-Dwelling Ambush Predators on Pollination Systems

Abbott, Kevin Richard 09 1900 (has links)
The interaction between pollinators and flowers affects the fitness of both pollinators and flowering plants, which can result in the co-evolution of pollinator and floral traits. Some pollination systems contain flower-dwelling ambush predators that attack visiting pollinators. This interaction could result in co-evolution of predator and pollinator traits as is typical in predator-prey systems. The presence of these predators could also have indirect negative fitness effects on flowering plants by killing or deterring pollinators. This raises the possibility that predator and floral traits also co-evolve. Furthermore, it is possible that this system is best described as a three-species game where predator, pollinator, and floral traits all co-evolve. The ultimate goal of my thesis is to explore this possibility. This is achieved in Chapter 5, which consists of a game theory model of the co-evolution of floral colour with predator and pollinator behavioural strategies. This model is novel, both within the pollination context described here and within a wider context. Furthermore this model is the first to propose that the evolution of floral colour might be affected by the presence of flower-dwelling ambush predators. This is particularly significant given that there has been little discussion about what floral traits might be adaptations to the presence of these predators. A secondary goal of this thesis is to explore how pollinators detect and respond to the presence of flower-dwelling ambush predators as an important subcomponent of predator-pollinator-flower co-evolutionary dynamic. Chapter 2 demonstrates that bumblebees avoid evidence of past predation events, and Chapter 3 demonstrates that the honeybee recruitment dance is affected by exposure to cues of predation risk in a way that should reduce the colony's exposure to predators. Chapter 4 is a model that suggests novel factors that might affect how a population of pollinators distributes itself between predator-free and predator-containing flowers. / Thesis / Doctor of Philosophy (PhD)
67

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.
68

Blomsterlupin versus tre inhemska ärtväxtarter : Jämförelser av besöksfrekvens och pollineringseffektivitet hos olika grupper av insektspollinatörer / Garden lupin versus three native legume species : Comparisons of visitation frequency and pollination effectivity for different groups of insect pollinators

Westling, Tobias January 2023 (has links)
Red clover (Trifolium pratense) is currently used as a green fertilizer for agriculture in northern Sweden. However, due to its low resistance against diseases and a minimal benefit to local pollinators, there is a need to find alternative native species that maximize the benefits for pollinators and agriculture. Garden lupin (Lupinus polyphyllus), another legume, is an invasive alien species in Sweden that may affect the behavior of pollinators and therefore the pollination success of local plant species. The main aim of this study was to increase the knowledge of the legumes cow vetch (Vicia cracca), garden lupin, marsh pea (Lathyrus palustris) and red clover by observing their insect visitors and potential pollinators. The work was divided into subproject 1 (delprojekt 1) and subproject 2 (delprojekt 2). Delprojekt 1 studied insect visitation frequencies in one plot where garden lupin, cow vetch and red clover grew together in Burträsk, while delprojekt 2 studied insect pollination effectivity in two plots where one plot (Fäbodsanden) contained only marsh pea and the other plot (Skäret) contained both garden lupin and marsh pea. Data were collected via field observations. In ‘delprojekt 1', both bumblebees and solitary bees showed a significantly higher visit frequency to garden lupin than to cow vetch and red clover. In ‘delprojekt 2’, flies showed a significantly higher pollination effectivity on garden lupin than on marsh pea in Skäret. Both flies and bumblebees showed a significantly higher pollination effectivity on marsh pea in Fäbodsanden than in Skäret. This indicate that visitation frequencies to cow vetch and red clover as well as pollination effectivity on marsh pea may be affected by the presence/absence of garden lupin. For future studies, examples on how to extend the knowledge even further on plant-pollinator interactions are suggested.
69

Fenologia reprodutiva, polinização e voláteis florais do cambuci (Campomanesia phaea - Myrtaceae) / Reproductive phenology, pollination and flower volatiles of the cambuci (Campomanesia phaea - Myrtaceae)

Cordeiro, Guaraci Duran 06 March 2015 (has links)
A família Myrtaceae tem muitas espécies frutíferas, algumas são utilizadas comercialmente, entre elas o cambuci (Campomanesia phaea). Os objetivos deste trabalho foram descrever a fenologia reprodutiva, a biologia floral, o sistema reprodutivo e identificar os polinizadores do cambuci para gerar novos conhecimentos que possam contribuir com a produtividade desta espécie. O estudo de fenologia reprodutiva foi conduzido por dois anos, em área de ocorrência natural e área de cultivo comercial. As fenofases (floração e frutificação) foram monitoradas com duas métricas: Índice de atividade (sincronia) e Índice de intensidade (intensidade - Fournier) e correlacionadas com fatores abióticos (temperatura, pluviosidade e comprimento do dia). Os resultados mostraram que a floração e frutificação na área de ocorrência natural e cultivo foram diferentes, mesmo sob mesmas condições climáticas. A floração e frutificação foram mais intensas e sincrônicas na área de cultivo. Os fatores abióticos não explicaram estas diferenças nas fenofases entre as áreas de estudo, porém a adubação do solo e diversidade de polinizadores tiveram papel importante. No estudo de polinização de C. phaea foram observados a duração de antese, recursos florais, receptividade do estigma e viabilidade polínica. O sistema reprodutivo de C. phaea foi investigado baseado na razão P:O e pelos experimentos de polinização manual. Os visitantes florais foram capturados e os polinizadores mais eficientes foram determinados, conforme número de pólen depositado no estigma e número de frutos produzidos. As flores de C. phaea duram dois dias, são hermafroditas e têm o pólen como o único recurso disponível para os visitantes florais. A antese é noturna e começa em torno das 5 h. O sistema reprodutivo de C. phaea é o autoincompatível. Foram coletadas 52 espécies de visitantes florais e entre elas as mais eficientes na polinização foram as abelhas noturnas e crepusculares (Megalopta sodalis, Megommation insigne, Ptiloglossa latecalcarata e Zikanapis seabrai). Além destas abelhas, as flores de C. phaea também foram visitadas e polinizadas por Apis mellifera nos períodos crepusculares e diurnos. Para entender como as abelhas noturnas/crepusculares encontram as flores do cambuci no escuro foram coletadas amostras dos voláteis florais (a noite e durante o dia), pelo método de dynamic headspace e posteriormente analisados por GC-MS. Experimentos eletroantenográficos (GC-EAD) e biotestes foram realizados para testar se os compostos identificados das flores do cambuci são capazes de estimular respostas eletrofisiológicas e comportamentais nas abelhas noturnas/crepusculares. Foram encontrados 14 compostos voláteis nas flores de C. phaea, os mesmos nas amostras da noite e do dia, embora a composição relativa do odor tenha diferido entre os dois períodos. A emissão dos voláteis é maior a noite durante a atividade das abelhas noturnas/crepusculares, e alguns compostos são mais eminentes durante a noite (ex, 1-Octanol) e outros ao dia (ex, 2-Phenylethanol). As abelhas noturnas foram atraídas para os odores sintéticos da flor do cambuci. Apis mellifera também respondeu positivamente ao teste eletroantenográfico e biotestes. Os resultados mostraram que os voláteis emitidos a noite pelas flores de C. phaea tem função atrativa para as abelhas noturnas/crepusculares, e sugere que 1-Octanol possa ser o composto chave nesta atração. / The family Myrtaceae has many fruiting species, some are commercially explored. Among those species is the cambuci (Campomanesia phaea). The objectives this work were to describe the reproductive phenology, the floral biology, the reproductive system, and to identify the pollinators of cambuci in order to generate new knowledge that may help increase the productivity of this species. The study about reproductive phenology was conducted for two years, in an area of natural occurrence and in a commercial crop. The phenophases (flowering and fruit set) were monitored with Activity index (synchrony) and Intensity index (Fournier intensity) and correlated with abiotic factors (temperature, rainfall, and day length). The results showed that flowering and fruit set of C. phaea in natural area and crop were different even under same climatic conditions. The flowering and fruit set were more intense and synchrony in the crop. The abioctic factors do not explain these differences in the phenophases between the study areas, but other variables, such as soil fertilization and pollinator diversity, play an important role. In the pollination study of C. phaea were observed the anthesis duration, floral resources, stigma receptivity, and pollen viability. The reproductive system of C. phaea was investigated based on the P:O ratio and by carrying out manual pollination tests. The flower visitors were captured and determined the most efficient pollinators, according to effectiveness by number of pollen grains deposited in the stigma and number of fruit set. The flowers of C. phaea last two days, are hermaphrodite, and have pollen as the only resource offered to flower visitors. Its anthesis is nocturnal and begins around 5 h. The reproductive system of C. phaea is self-incompatible. Were collected 52 species of flower visitors and among them the most efficient in pollination were nocturnal and crepuscular bees (Megalopta sodalis, Megommation insigne, Ptiloglossa latecalcarata e Zikanapis seabrai). Besides these bees, the flowers of C. phaea flowers were also visited and pollinated by Apis mellifera in crepuscular and diurnal periods. In order to understand how the nocturnal/crepuscular bees find cambuci flowers in darkness flower volatiles were collected (at night and during the day) by dynamic headspace method and after analyzed by GC-MS. In addition, electroantennographic (GC-EAD) and behavioural experiments (bioassays) were performed to test if compounds identified from cambuci flowers are capable in eliciting electrophysiological and behavioural responses in nocturnal/crepuscular bees. In total 14 volatiles compounds were found in C. phaea flowers, the same in the night and day samples. Although, the relative scent composition differed between these two periods. The volatile emission is higher during the activity of nocturnal/crepuscular bees, and some compounds are more eminent during the night (e.g., 1-Octanol) and some during the day (e.g., 2-Phenylethanol). The nocturnal/crepuscular were attracted by synthetic scent of the cambuci flowers. Apis mellifera also showed positive responds towards for electroantennographic and behavioural bioassays. The results showed that volatiles emitted at night by C. phaea flowers have attractive function to nocturnal/crepuscular bees, and suggest that 1-Octanol can be the key compound for this attraction.
70

Modelo para análise de desempenho do processo de replicação de dados em portais de biodiversidade. / Model for performance analysis of the replication process of biodiversity portal data.

Salvanha, Pablo 08 December 2009 (has links)
Atualmente muitas instituições mantêm coleções de espécimes biológicas, e através de ferramentas computacionais digitalizam e disponibilizam seus dados para acesso através de portais de dados de biodiversidade. Um exemplo deste tipo de ferramenta é o portal de espécimes utilizado pelo GBIF (Global Biodiversity Information Facility), que centraliza em suas bases de dados milhões de registros, provenientes de instituições de diferentes localizações. A replicação das bases de dados locais nos portais é realizada através da utilização de protocolos (DiGIR / TAPIR) e esquemas de dados (DarwinCore). Entretanto a execução desta solução demanda uma grande quantidade de tempo, englobando tanto a transferência dos fragmentos de dados como o processamento dos mesmos dentro do portal. Com o crescimento da digitalização de dados dentro das instituições, este cenário tende a ser agravado cada vez mais, dificultando assim a manutenção de dados sempre atualizados dentro dos portais. Esta pesquisa propõe uma análise do processo de replicação de dados com objetivo de avaliar seu desempenho. Para isto é utilizado o portal de biodiversidade de polinizadores da IABIN como estudo de caso, o qual possui, além da replicação de dados convencionais o suporte a dados de interação. Com os resultados desta pesquisa é possível simular situações antes da efetivação das mesmas, prevendo assim qual será o seu desempenho. Adicionalmente estes resultados podem contribuir para melhorias futuras deste processo, visando a diminuição do tempo necessário da disponibilização dos dados dentro de portais de biodiversidade. / Currently many institutions keep collections of biological specimens, and through computational tools they digitalize and provide access to their data through biodiversity data portals. An example of this tool is the specimens portal used by GBIF (Global Biodiversity Information Facility), which focuses on its databases millions of records from different institutions around the world. The replication of databases in those portals is accomplished through the use of protocols (DiGIR / TAPIR) and data schemas (DarwinCore). However the implementation of this solution demands a large amount of time, encompassing both, the transfer of fragments of data as processing data within the portal. With the growth of data digitalization within the institutions, this scenario tends to be increasingly exacerbated, making it hard to maintenance the records up to date within the portals. This research proposes analyze the replication process data to evaluate its performance. To reach this objective is used the IABIN biodiversity portal of pollinators as study case, which support both situations: the conventional data and the interaction data replication. With the results of this research is possible to simulate situations before its execution, thus predicting what will be its performance. Additionally these results may contribute to future improvements of this process; in order to decrease the time required to make the data available in the biodiversity portals.

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