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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.
1

Variation in and Responses to Brood Pheromone of the Honey Bee (Apis mellifera)

Metz, Bradley N. 2009 December 1900 (has links)
Brood pheromone of the honey bee, (Apis mellifera) has been shown to elicit a wide array of primer and releaser effects on non‐foragers and foragers leading to the regulation of nursing, pollen foraging, and behavioral development such that the behavior of the colony may be regulated by the amount and condition of the larvae. To date, all studies into the effects of brood pheromone have either used uncharacterized whole extracts or a single blend of brood pheromone characterized from a population of honey bees in France. The variation in the relative proportions of the ten fatty‐acid ester components that characterize brood pheromone and some effects of this variation on pollen foraging and sucrose response thresholds were therefore observed. The objectives met in this dissertation were to determine whether changes in brood pheromone component proportions (blend) or amount communicates larval nutritional status and reports the results of observations of nurses and foragers in response to blends of brood pheromone from deprived and‐non deprived larvae, to measure how changes in brood pheromone blend changed pollen foraging behavior and if such changes could account for the pollen foraging differences between Africanized and European bees, and finally to observe the effects of exposure time on brood pheromone blend and to observe whether non‐foragers made contact with the pheromone. Brood pheromone was found to vary by larval rearing environment, but did not elicit the expected behaviors that would support a cue of nutritional status. Brood pheromone also varied significantly by mitochondrial lineage/population source and responses to brood pheromone appeared to be coadapted to blend, suggesting that brood pheromone may be important in race recognition. Finally, brood pheromone varied significantly over time and was found to be removed from sources by bees, suggesting possible mechanisms for loss of effect. Combined the results of this research indicate that brood pheromone blend differences lead to profound changes in colony behavior related to pollen foraging and food provisioning, providing novel tools for colony manipulation and mechanisms for understanding brood rearing division of labor and chemical communication.
2

Response Thresholds Predict Domestic Labor Conflict and Labor Allocation in Marital Dyads

January 2012 (has links)
abstract: Guided by Alberts, Tracy and Trethewey's (2011) integrated theory of the division of domestic labor, this dissertation examined the influence of domestic labor response threshold (i.e., the point at which one is sufficiently disturbed by a task undone so as to feel compelled to attend to it) on domestic labor performance and domestic labor conflict. Three-hundred-ten heterosexual participants (155 marital dyads; average marriage length of 20 years) completed an online questionnaire about their performance of household labor, household labor conflict, and response thresholds. Response thresholds were assessed using traditional verbal measures as well as two visual (i.e., photographic) measures developed for this investigation. The data were analyzed using three methods of dyadic data analysis: structural equation modeling, repeated measures multivariate analysis of variance (MANOVA), and actor-partner interdependence models using multilevel modeling. Results indicate that the lower one's response threshold, and the higher one's partner's response threshold, the greater one's contributions to household tasks. Additionally, the lower one's response threshold, and the higher one's partner's response thresholds, the more likely the demand-withdrawal pattern is to emerge in domestic labor conflicts. Finally, mutual avoidance is more likely when one partner perceives that it is less costly to complete domestic work than to engage in conflict about it, or when one partner perceives that domestic labor is not a worthwhile or appropriate conflict topic. Contributions of this investigation include support for the integrated theory of the division of domestic labor, increased understanding of how individual differences (working in concert with actor sex) contribute to domestic labor allocation and conflict, a more sensitive measure of response threshold, and preliminary evidence of the "logics" of avoidance of domestic labor conflict. / Dissertation/Thesis / Ph.D. Communication 2012
3

Manejo de Neoleucinodes elegantalis (Guenée) (Lepidoptera : Crambidae) em tomateiro : efeito ovicida, deterrência de oviposição e iscas tóxicas / Management of Neoleucinodes elegantalis (Guenée) (Lepidoptera :Crambidae) in tomato: ovicide effect, oviposition deterrence and toxic baits

FRANÇA, Solange Maria de 02 February 2009 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-11-30T12:44:33Z No. of bitstreams: 1 Solange Maria de Franca.pdf: 508760 bytes, checksum: daf7b92b1d8c33b9a4b65c6ecc2d847b (MD5) / Made available in DSpace on 2016-11-30T12:44:33Z (GMT). No. of bitstreams: 1 Solange Maria de Franca.pdf: 508760 bytes, checksum: daf7b92b1d8c33b9a4b65c6ecc2d847b (MD5) Previous issue date: 2009-02-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Among the pests that attack tomato, to the tomato fruit borer, Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae), is responsible for significant losses in productivity. It’s control is usually done by excessive insecticide applications. Thus, researches with new tactics that aims to reduce pesticides use are essential to better manage this pest. The present study evaluated the ovicide effect, oviposition preference, food preference, threshold of food intake, and toxic effect of insecticides associated with attractive food sources, seeking the control of N. elegantalis. The LCs50 for N. elegantalis eggs varied from 0.029 to 4.19% according to the following sequence of decreasing toxicity: deltametrin > NeemPro > Natunem® > Neemseto®. According to the toxicity rate, deltametrin was 144 times more toxic than Neemseto ®. The highest and lowest deterrence was obtained for Natuneem® and deltametrin, respectively. Thus, sucrose, molasses, honey and orange juice were selected to determine the threshold concentrationcapable of stimulating feeding of N. elegantalis adults. Sucrose and honey were the most attractive food sources, regarding the number of lands, landing time, and feeding time of adults of N. elegantalis. In contrast, only sucrose showed a positive correlation among the tested concentrations, the landing time, and the feeding time of adults and males. The toxic effect of insecticides associated with honey 10% was also tested. The insecticides did not affect negativelythe attraction of N. elegantalis adults. Carbaryl, cartap, deltamethrin, fenpropatrina, indoxacarb, lambda-cyhalothrin, and lufenuron caused 100% mortality in males and females and adults of N. elegantalis, after 24h exposure, suggesting that they are promising for using in toxic baits. / Dentre as pragas que infestam a cultura do tomateiro, destaca-se a broca-pequena, Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae), responsável por perdas significativas na produtividade. Seu controle é feito, comumente, com aplicações excessivas de inseticidas. Assim, pesquisas visando reduzir o uso de agrotóxicos são essenciais para o manejo mais adequado dessa praga. No presente trabalho avaliou-se o efeito ovicida, a preferência para a postura, a preferência alimentar, o limiar de ingestão e o efeito tóxico de inseticidas associados a atraentes, visando o controle de N. elegantalis. As concentrações letais (CL50s) dos inseticidas para ovos de N. elegantalis variaram de 0,029 a 4,19%, obedecendo à seguinte ordem decrescente de toxicidade: deltametrina > NeemPro > Natunem® > Neemseto®. De acordo com razão de toxicidade, deltametrina foi 144 vezes mais tóxico, em relação a Neemseto®. A maior e menor deterrência de oviposição de N. elegantalis foram obtidas, respectivamente, por Natuneem® edeltametrina. Foram selecionados os atraentes sacarose, melado, mel e suco de laranja, visando determinar o limiar de concentração capaz de estimular a alimentação de adultos de N. elegantalis. A sacarose e o mel apresentaram o melhor desempenho, em relação ao número e tempo de pouso e à alimentação de adultos de N. elegantalis. No entanto, apenas sacarose apresentou correlação positiva entre as concentrações testadas e o pouso e a alimentação deadultos e machos. O efeito tóxico de inseticidas associados ao mel a 10% também foi testado. Os inseticidas não afetaram negativamente a atração de adultos de N. elegantalis. Carbaril, cartape, deltametrina, fenpropatrina, indoxacarbe, lambda-cialotrina e lufenurom causaram 100% de mortalidade em adultos, machos e fêmeas de N. elegantalis, após 24 h de exposição, mostrando-se promissores para o uso em iscas tóxicas.

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