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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.
81

Abelhas visitantes das flores do urucuzeiro (Bixa orellana L.) e suas eficiÃncias de polinizaÃÃo / Visitors of the bees flowers(Bixa orellana L.) and pollination efficiency

Francisca Ligia Aurelio Mesquita 26 February 2008 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A pesquisa de campo foi conduzida na Fazenda Kiara Coeli localizada no municÃpio de Caucaia, estado do CearÃ. A coleta dos dados ocorreu de marÃo a agosto de 2007. Em um plantio de 6 ha constituÃdo por urucuzeiros hÃbridos. O trabalho objetivou conhecer os requerimentos de polinizaÃÃo do urucuzeiro (Bixa orellana L.), identificar seus visitantes florais e avaliar a eficiÃncia polinizadora dos agentes biÃticos mais freqÃentes nas flores da cultura. Os requerimentos de polinizaÃÃo foram avaliados por estudos de biologia floral, receptividade do estigma e tratamentos de polinizaÃÃo livre, polinizaÃÃo manual cruzada, autopolinizaÃÃo manual, polinizaÃÃo restrita com filà e polinizaÃÃo restrita com papel; os visitantes florais foram capturados para identificaÃÃo e suas freqÃÃncias e comportamento de pastejo observados usando transetos percorridos regularmente no cultivo. A eficiÃncia de polinizaÃÃo dos visitantes florais mais freqÃentes Ãs flores foi feita por meio de visitas Ãnicas e avaliaÃÃo do tamanho, peso e nÃmero de sementes dos frutos produzidos. Os resultados mostraram que as flores do urucuzeiro duram apenas um dia e possuem anteras poricidas que necessitam serem vibradas para liberar pÃlen, apresentam receptividade apenas no perÃodo da manhÃ, especialmente entre 9:30 e 10:30 h, e produzem significativamente (p<0,05) mais frutos sob polinizaÃÃo cruzada do que autopolinizaÃÃo. As flores foram visitadas por insetos das Ordens: Diptera, Coleoptera e Hymenoptera, principalmente 13 espÃcies de abelhas das famÃlias Antophoridae, Apidae, Halictidae e Andrenidae, a saber: Xylocopa frontalis, Xylocopa grisensces, Xylocopa muscaria, Exomalopsis analis, Apis mellifera, Melipona subnitida, Partamona sp., Trigona spinipes, Eulaema nigrita, Euglossa sp, Megalopta sp., Augochloropsis sp. e Oxaea sp. As abelhas coletaram exclusivamente pÃlen, principalmente no perÃodo da manhà e variaram em freqÃÃncia, comportamento de pastejo e eficiÃncia em vingar frutos com apenas uma visita à flor (p<0,05). Concluiu-se que a polinizaÃÃo do urucuzeiro à predominantemente xenÃgama e dependente de agentes biÃticos, principalmente abelhas; o comportamento de pastejo do visitante floral à de fundamental importÃncia para determinar sua eficiÃncia como polinizador do urucuzeiro, e as abelhas Xylocopa frontalis, Augochloropis sp. e Eulaema nigrita, por ordem de importÃncia, foram os polinizadores mais efetivos na Ãrea estudada, devendo suas presenÃas serem incrementadas no plantio / The research was carried out in the farm Kiara Coeli situated in the county of Caucaia, state of CearÃ, Brazil. Data gathering took place from March to August 2007. In a 6ha crop made up of hybrids annatto plants. The work aimed to know the pollination requirements of annatto (Bixa orellana L.), to identify its floral visitors and the pollination efficiency of the most frequent floral visitors. Pollination requirements were evaluated by means of studies in floral biology, stigma receptivity and treatments of open pollination, hand cross pollination, self-pollination, muslin bag restricted pollination and paper bag restricted pollination; floral visitors were captured for identification and their frequency and foraging behavior were observed using transects which were walked in a regular basis throughout the day. Pollination efficiency of the most frequent floral visitors was assessed allowing one-floral visit only, and measurements of size, weight and number of seeds produced per fruit. Results showed that the annatto flowers last only one day and bear poricidal anthers that need to be vibrated to release pollen, are receptive only in the morning shift, especially between 9:30 and 10:30 h, and produce significantly (p<0,05)more fruits under cross pollination than self-pollination. Flowers were visited by insects of the Orders Diptera, Coleoptera and Hymenoptera, mainly 13 bee species belonging to the families Antophoridae, Apidae, Halictidae and Andrenidae, namely: Xylocopa frontalis, Xylocopa grisensces, Xylocopa muscaria, Exomalopsis analis, Apis mellifera, Melipona subnitida, Partamona sp., Trigona spinipes, Eulaema nigrita, Euglossa sp, Megalopta sp.,Augochloropsis sp. and Oxaea sp. Bees collected exclusively pollen, mainly early in the morning and varied (p<0,05) in frequency to flowers, foraging behavior and pollinating efficiency with only one floral visit. It was concluded that pollination in annatto is mainly xenogamous and dependent upon biotic agents, especially bees; the floral visitorâs foraging behavior is of paramount importance to determine its pollination efficiency of annatto flowers, and the bee species Xylocopa frontalis, Augochloropis sp. and Eulaema nigrita, by order of importance, were the most effective pollinators in the studied area, and their presence should be improved in the site
82

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

Guaraci Duran Cordeiro 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.
83

Not All Pollinator Gardens are Created Equally: Determining Factors Pertinent to Improving Pollinator Garden Effectiveness

Watson, Travis 01 May 2021 (has links)
Increasing evidence documenting the decline of insect populations, resulting from increasing human disturbances has resulted in efforts to establish pollinator gardens to provide additional resources for insect populations. However, our understanding of biotic and abiotic garden characteristics important for attracting and sustaining pollinator diversity is limited. Here, we evaluated 17 pollinator gardens to evaluate the effect of five biotic and three abiotic garden characteristics on pollinator species richness, abundance, and proportional representation of four pollinator functional groups. Plant species richness positively influenced pollinator richness and negatively influenced flower visitation. Bombus proportional abundance responded to several variables (distance to vegetation, plant species richness, floral symmetry, floral native status, habitat type), and decreases in their proportional representation were accompanied by increasing proportions of other insect groups. Our results suggest any size, diverse, native pollinator gardens can improve pollinator diversity, and small-scale pollinator gardens should favor functional groups adapted for the habitat type.
84

Factors influencing bee communities and pollination services across an urban environment

Burdine, Justin D. 07 May 2019 (has links)
No description available.
85

Impact of Spatial Distance and Pollinators on Floral and Fruit Bacterial Communities of Solanum carolinense

Heminger, Ariel Renee 03 August 2023 (has links)
Fruits and flowers house microbial communities that are unique from the rest of the plant. While a great deal is known about a handful of symbiotic microbes associated with roots and leaves, the microbial communities of fruits and flowers have received considerably less attention. Fruits are reproductive tissues that house, protect, and facilitate the dispersal of seeds, and thus they are directly tied to plant reproductive success. Fruit and flower microbial communities may, therefore, also impact plant fitness. This dissertation examines how fruit bacterial communities, as determined using the 16S rRNA gene marker, are shaped across spatial and environmental gradients and the role of pollinators in shaping floral bacterial communities among natural populations of Solanum carolinense. There have been limited studies on how spatial distance influences bacterial communities found in and on fruit tissue and the role of pollinators in shaping floral bacterial communities. The first study addresses how bacterial communities in fruit change across similar environmental conditions at fine spatial scales (2 to 450 m). Overall, no differences were found in observed richness or bacterial community composition. Next, the role that generalist pollinators might play in shaping these communities was tested using pollinator exclusion cages. Here we found that generalist pollinators do not play a large role in shaping floral bacterial communities in Solanum carolinense. Comparing bacterial community diversity between caged and uncaged flowers, via PCoA we found no significant clustering of samples. In contrast, significant clustering was detected between flowers and bee pollen baskets. Together these results suggested that environmental factors may be more important in shaping floral bacterial communities. To test this, we sampled 9 populations along a 337 km latitudinal transect and again used the 16S rRNA gene to characterize bacterial communities. We did not identify a significant correlation between distance and bacterial community composition in either the total nor endophytic community in the fruit. Results from these studies suggest that while there is some evidence for environmental effects shaping fruit and flower communities, other factors such as host selection (e.g., secondary compounds in fruit) also likely play an important role in shaping bacterial communities. / Doctor of Philosophy / Fruit and flowers are directly tied to plant reproduction, yet little is known about the bacterial communities associated with these important organs, especially compared to other plant tissues. This dissertation aims to address gaps in our knowledge regarding how spatial distance and pollinators influence fruit and floral bacterial communities. Specifically, how does bacterial community composition (what bacteria taxa are present or not and how abundant the bacterial taxa are) change based on spatial distance. Studies were conducted at both fine (under 0.5 km) and broad (337 km) scales to determine if a pattern was observed between increasing distance and how distinct the bacterial community composition is. There was no significant correlation between spatial distance and bacterial community composition at fine spatial distances, however there were high levels of dissimilarity in the bacterial communities sampled across fine spatial scales. This led to the investigation of pollinators, which directly interact with flowers and may act as a source of bacterial community transmission in the flower and fruit bacterial communities as they move around the landscape. To address the role that pollinators play in shaping bacterial communities in the fruits an exclusion cage study was used to prevent pollinators from interacting with a subset of flowers. Pollen baskets (pollen that was collected by the pollinator and is found on the legs of pollinator) were also collected from pollinators to determine what bacteria may be present on the pollinator. Pollen baskets may also represent what bacteria may have been picked up by the pollinator at the site. It was observed that caged and uncaged samples were similar to one another, which suggest that pollinators were not adding new bacteria nor changing the bacterial composition in the flowers. Yet, the pollen baskets (from the pollinator) were unique from the caged and uncaged floral samples. To further investigate what factors may be at play in shaping the fruit bacterial community the transect was expanded to 337 km to determine if there was an observable relationship between spatial distance and bacterial community composition. The relationship between spatial distance and bacterial community composition was not significant in either the endophytic (internal bacterial community) or the total fruit bacterial community (which represented external and internal bacterial communities). Similar to the fine spatial scale study, there were high levels of dissimilarity in the bacterial community that was observed across sites. Results from these studies may suggest that there are other factors that play a larger role in shaping bacterial communities in fruit and flower tissue. These could include the host plant and the production of secondary compounds, which in some cases can act as antimicrobial compounds, and enhance or inhibit the growth of specific bacterial taxa. Environmental factors such as wind and rainfall may have influenced the bacterial community composition. It is likely that environmental factors play a role in shaping floral and fruit bacterial communities. However, it is still unclear what factors shape fruit and floral bacterial communities are. This study provides the foundation for future studies to address additional factors that shape fruit and flower bacterial communities.
86

Is Heterospecific Pollen Receipt the Missing Link in Understanding Pollen Limitation of Plant Reproduction?

Ashman, Tia Lynn, Arceo-Gómez, Gerardo, Bennett, Joanne M., Knight, Tiffany M. 01 January 2020 (has links)
No description available.
87

Impacts of Urban Greenspace Management on Beneficial Insect Communities

Spring, MaLisa R. 10 August 2017 (has links)
No description available.
88

Propolis: Immersive Environment

Alarid, Renee Aurelia 15 February 2021 (has links)
Propolis – Creating and using an immersive 2D honey bee environment to educate children between the ages of 3-10, about the importance of honey bees. This capstone project will showcase this researcher's skills in graphic design, spatial sound, architecture, exhibition design, and character illustration. Within this structure, individuals will be able to observe, determine, and make comparisons between a healthy bee colony and one that is fragile and dying. / Master of Fine Arts / "Honey bees have been on the decline. As of 2016, eight species of bees made it on the United States (U.S.) endangered species list. It reported that the decline of pollinators is due to industrial agriculture, parasites, pathogens, and climate change" (Contributors 2020). The loss of habitat and lack of nectar is due to monocultures and bee-killing pesticides. These are significant threats to honey bees and wild pollinators. There is a need for good, clean food providing for a healthy existence for the honey bee. When bees have proper nutrients, the result is a healthy hive that gives mature bees a better chance to fight off diseases. To showcase the life of a honey bee, this researcher created an immersive environment that simulates a hive structure. The structure, along with the motion graphics and critical takeaway printed pieces, is to help children between the ages of 3-10 understand the importance of honey bees. By comparing healthy and unhealthy bees in their natural habitat in an illustration format, the children could empathize with the honey bees. Hopefully, they will one day change the fate of these amazing creatures. The immersive environment will emulate a spatial audio, 2D character illustration, and animation projected onto a honeycomb structure. Custom seed packets and a brochure will accompany the immersive environment to allow the children to plant a bee-friendly garden and to learn more about the honey bees. This capstone project will showcase the researcher's skills in graphic design, spatial sound, architecture, exhibition design, and character illustration. This structure will allow individuals to observe, determine, and make comparisons between a healthy colony and one that is fragile and dying.
89

Influence of spatial and temporal factors on plants, pollinators and plant-pollinator interactions in montane meadows of the western Cascades Range

Pfeiffer, Vera W. 01 June 2012 (has links)
Montane meadows comprise less than 5% of the landscape of the western Cascades of Oregon, but they provide habitat for diverse species of plants and pollinators. Little is known about plant-pollinator network structure at these sites. This study quantified plant-pollinator interactions over the summer of 2011, based on six observations of 10 permanent subplots in 15 meadows, stratified by size and isolation. The study examined (1) relationships between richness and abundance of flowers, pollinators, and interactions; (2) distribution of abundance and richness of flowers, pollinators, and interactions with regards to surrounding meadow habitat; (3) change in flower and pollinator abundance over the season; (4) factors associated with the presence of various guilds of pollinators; and (5) the structure of plant-pollinator networks. The study showed that (1) richness of pollinators increased 2x faster than richness of flowers with increased abundance; (2) density of flowers and interactions was positively correlated with meadow size and diversity of pollinators and interactions were both correlated with surrounding habitat at two spatial scales; (3) peak flower abundance coincided with or preceded peaks in pollinator populations; (4) abundance of three guilds of bees exhibited different patterns of association to surrounding habitat and meadow soil moisture corresponding to various dispersal potential and phenology of guild species; and (5) the number of network pairings for plants and pollinators increased with increasing species richness of potential interaction partners and all networks were found to be significantly nested. Results of this study indicate that plant-pollinator networks are complex assemblages of species, in which spatial and temporal patterns of habitat affect species composition and network structure. In particular, flower and pollinator abundance and richness are depressed in small and isolated meadows. Significant nestedness emerged as a pattern of network level organization across the study meadows. / Graduation date: 2013
90

Selection and Floral Evolution in Platanthera bifolia and P. chlorantha (Orchidaceae)

Maad, Johanne January 2002 (has links)
Natural selection mediated by pollinators has influenced the evolution of floral diversity of the flowering plants (angiosperms). The scope of this thesis was to study: 1) phenotypic selection, 2) mating systems, and 3) floral shifts involved in plant speciation. Model plant species were Platanthera bifolia and P. chlorantha (Orchidaceae). These orchids are moth-pollinated, strictly co-sexual (bisexual flowers), and produce a spike that displays 10-20 white flowers. I explored the influence of characters on plant fitness by using multiple linear regressions. Pollen removal (male fitness) and fruit set (female fitness) increased with more flowers per plant in three P. bifolia populations. There was selection towards longer spurs in a dry year when average spur length was shorter than in normal-wet years. Female function was sensitive to drought, which enabled an application of the male function hypothesis of floral evolution (Bateman's principle). The results show that selection may vary between populations, years, and sex-functions. I examined inbreeding by estimating levels of geitonogamy (self-pollination between flowers of an individual) with an emasculation method in two P. bifolia populations. Geitonogamy did not vary with inflorescence size. Levels of geitonogamy was 20-40% in the smaller, but non-significant in the larger population. This may relate to lower number of possible mates and pollinator activity in the smaller population. Platanthera bifolia exhibits the ancestral character state of tongue-attachment of pollinia on the pollinator. Its close relative P. chlorantha attaches its pollinia onto the pollinator's eyes. To explore the mechanism of a floral shift, pollination efficiency and speed was compared between the two species. The results showed no differences in pollination efficiency, but P. chlorantha had faster pollen export and import. Efficiency of pollination in terms of speed may cause floral shifts, and thus speciation.

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