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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

Trichogramma larval behaviour and the refinement of an artificial cell line diet /

Heslin, Leeane Maree. January 2005 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.
2

Reproductive strategies of males in the egg parasitoid Trichogramma turkestanica Meyer (Hymenoptera:Trichogrammatidae)

Martel, Véronique. January 2007 (has links)
In most animals, males are assumed to have access to an unlimited supply of sperm, while females produce few eggs that are large and costly to produce. In parasitoids, there is a paradigm to the effect that males are polyandrous, inseminate as many females as possible and express no optimization in their behaviours. In reality, sperm production incurs non-trivial costs. Because sperm are transferred in ejaculates and that their cost is greater than that of individual sperm, males can gain by carefully allocating their ejaculates. In this thesis I have investigated different aspects of males' reproductive strategies, mainly sperm and time allocation, in the egg parasitoid Trichogramma turkestanica Meyer (Hymenoptera: Trichogrammatidae). / In T. turkestanica, mating mainly occur on the emergence patch. However, results show that mating opportunities are not distributed equally among males and 2.9% of successful males are sperm-depleted when they disperse from the emergence patch. Nevertheless, 97.1% of males disperse non sperm-depleted, suggesting off-patch mating potential. Male T. turkestanica have thus an insemination capacity higher than necessary to inseminate the females present on the emergence patch, a pattern that seems to be common among parasitic wasps. / On the emergence patch, both virgin and mated females can be encountered. Males are able to discriminate between those mates and prefer virgin ones. This preference is stronger for energy- and time-limited males. / Sperm competition risks and/or intensity are important for males that decrease their sperm investment when the number of rivals increases. Such response is optimal when the benefits from investing more sperm become lower than the costs of a low paternity assurance under intense sperm competition. / Finally, male T. turkestanica express behaviours enabling them to optimize their patch time exploitation. Depending on their evaluation of the patch quality, males modify their patch residence time. / This thesis shows that time- and sperm-limited male T. turkestanica are not simply maximizing the number of females inseminated, but rather maximize their lifetime fitness by optimizing sperm and patch time allocation.
3

Biology, behaviour and genetic diversity of Trichogramma aurosum Sugonjaev and Sorokina (Hymenoptera: Trichogrammatidae)

Samara, Rana January 2005 (has links)
Zugl.: Hohenheim, Univ., Diss., 2005
4

Viabilidade do uso de ovos de Mythimna sequax (Franclemont, 1951) (Lepidoptera: Noctuidae) e Anticarsia gemmatalis Hubner (Lepidoptera: Erebidae) estocados em nitrogênio líquido para a produção massal de Trichogramma Westwood (Hymenoptera: Trichogrammatidae)

Paixão, Magda Fernanda January 2016 (has links)
Orientador : Dr. Luis Amilton Foerster / Co-orientada : Profa. Dra. Marion do Rocio Foerster / Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Agronomia. Defesa: Curitiba, 11/03/2016 / Inclui referências : f. 103-112 / Área de concentração: Produção vegetal / Resumo: Este estudo teve por objetivo avaliar a viabilidade da estocagem de ovos de Mythimna sequax em nitrogênio líquido visando a produção massal de Trichogramma. A tese foi dividida em quatro capítulos, sendo o primeiro destinado à realização de estudos de base visando incrementar os índices de parasitismo e emergência de Trichogramma em ovos de M. sequax estocados em nitrogênio líquido. Foram avaliadas a influência da densidade de fêmeas de Trichogramma pretiosum no parasitismo de ovos estocados por 15 dias e o desempenho de fêmeas criadas em ovos estocados durante três gerações e comparadas com fêmeas criadas em ovos não estocados, a fim de verificar a necessidade de manter uma linhagem de Trichogramma criada em ovos estocados. No segundo capítulo, foi estudado a influência de ovos de M. sequax, tratados com crioprotetores antes do congelamento em nitrogênio líquido e ofertados ao parasitismo por T. pretiosum. Os ovos foram tratados com dimetilsulfóxido (DMSO), glicerol, sacarose, etilenoglicol e leite desnatado para criopreservação. O parasitismo destes ovos foi comparado com ovos não tratados estocados e não estocados. No terceiro capítulo, avaliou-se a capacidade reprodutiva de Trichogramma atopovirilia, Trichogramma exiguum, Trichogramma galloi e T. pretiosum em ovos de M. sequax estocados em nitrogênio líquido para determinar as espécies que apresentam melhor aceitação dos ovos estocados em nitrogênio líquido. Enquanto que no quarto capítulo, foram comparados os índices de parasitismo e emergência de T. pretiosum em ovos de Anticarsia gemmatalis e M. sequax estocados em nitrogênio líquido. Posteriormente foram determinados e quantificados por meio de espectroscopia de ressonância magnética nuclear (RMN) os metabólitos trealose, fosfocolina e maltodextrina presentes nos ovos desses dois hospedeiros. Após esses experimentos foram avaliadas a influência do tempo de estocagem (um, três, seis, nove e 12 meses) de ovos de M. sequax em nitrogênio líquido no parasitismo por T. atopovirilia e T. pretiosum. Com base nesses estudos verificou-se que a densidade ideal para os experimentos com T. pretiosum foi de uma fêmea para dez ovos; e que não há necessidade de manter uma linhagem de Trichogramma a partir de ovos estocados, pois não houve diferença nos parâmetros biológicos. Não há necessidade da adição de crioprotetores antes da estocagem dos ovos, uma vez que os maiores índices de parasitismo foram obtidos em ovos sem tratamento prévio. As espécies que mais se destacaram no parasitismo de ovos estocados foram T. atopovirilia e T. pretiosum. Ovos de A. gemmatalis não são viáveis à estocagem em nitrogênio líquido e apresentaram menor quantidade de trealose e maltodextrina do que os ovos de M. sequax, sendo que estes foram viáveis para estocagem em nitrogênio líquido por até 12 meses sem afetar os parâmetros biológicos das espécies de Trichogramma avaliadas. / Abstract: This study aimed to evaluate the viability of Mythimna sequax stored eggs in liquid nitrogen for the mass production of Trichogramma. The thesis was divided into four chapters, the first for the performing baseline studies to increase the parasitism and emergence of Trichogramma on M. sequax eggs stored in liquid nitrogen. The influence of the density of Trichogramma pretiosum females on parasitism of eggs stored for 15 days was evaluated. The performance of females reared for three generations on stored eggs was compared to females reared on nonstored eggs, to identify possible alterations in the parasitism capacity of stored produced adults in relation to non-stored ones. In the second chapter, has studied the influence of M. sequax eggs treated with cryoprotectants before freezing in liquid nitrogen and offered to parasitism by T. pretiosum. The eggs were treated with dimethyl sulfoxide (DMSO), glycerol, sucrose, ethylene glycol and skim milk for cryopreservation. The parasitism of the eggs was compared to eggs untreated stored and non- stored. In the third chapter, we evaluated the reproductive capacity of Trichogramma atopovirilia, Trichogramma exiguum, Trichogramma galloi and T. pretiosum from eggs of M. sequax stored in liquid nitrogen to determine the species with better acceptance of eggs stored in liquid nitrogen. In the fourth chapter the parasitism and emergence of T. pretiosum was compared on Anticarsia gemmatalis and M. sequax eggs stored in liquid nitrogen. After The trehalose metabolites, phosphocholine and maltodetrina present in eggs of these two hosts were determined and quantified by means of nuclear magnetic resonance spectroscopy (NMR). After these experiments were evaluated the influence of storage time (one, three, six, nine and 12 months) of M. sequax eggs in liquid nitrogen in parasitism by T. atopovirilia and T. pretiosum. Based on these studies it was found that the ideal density for the experiments with T. pretiosum was a female per ten eggs; and there is no need to maintain a Trichogramma strain from eggs stored because there was no difference in biological parameters. There is no need for the addition of cryoprotectant prior to storage of eggs, since the larger parasitism were obtained from untreated eggs.The species that stood out in the parasitism of stored eggs were T. atopovirilia and T. pretiosum. Anticarsia gemmatalis eggs are not viable for storage in liquid nitrogen and had lower amount of trehalose and maltodextrin than the M. sequax eggs, and these were viable for storage in liquid nitrogen for up to 12 months without affecting the biological parameters of assessed species of Trichogramma.
5

Reproductive strategies of males in the egg parasitoid Trichogramma turkestanica Meyer (Hymenoptera:Trichogrammatidae)

Martel, Véronique. January 2007 (has links)
No description available.
6

Sex allocation and mating structure in the egg parasitoids of the genus Trichogramma (Hymenoptera:Trichogrammatidae)

Martel, Véronique January 2003 (has links)
Haplodiploid Hymenoptera females control the sex of their progeny, and their sex allocation is influenced by several factors. The impact of intra- and interspecific competition and of inbreeding and outbreeding on sex allocation has been studied in some species of the egg parasitoid Trichogramma. The pre-mating dispersion has also been studied. Impact of competition on sex allocation was observed for Trichogramma minutum Riley and Trichogramma pintoi Voegele. These species were chosen because of the ease with which than can be distinguish. Results show that females of both species lay more males under intraspecific competition than alone, following the Local Mate Competition theory, while only T. pintoi modifies its sex ratio under interspecific competition. Multiparasitism and natural habitat could explain this shift in the sex ratio. Trichogramma minutum, T. pintoi and Trichogramma evanescens Westwood pre-mating dispersion show that most matings occur at the emergence site. However, the three species have a potential for off-patch mating, allowing genetic exchange between sub-populations. These three species were chosen because they are classified in different groups in the genus. Finally, T. evanescens did not modify its sex ratio following inbreeding or outbreeding. The incapacity to discriminate between kin and non-kin, insufficient genetic distance in outbreeding, or the population structure could explain these results.
7

Sex allocation and mating structure in the egg parasitoids of the genus Trichogramma (Hymenoptera:Trichogrammatidae)

Martel, Véronique. January 1900 (has links)
Thesis (M.Sc.). / Written for the Dept. of Natural Resource Sciences, Macdonald College of McGill University. Title from title page of PDF (viewed 2008/07/28). Includes bibliographical references.
8

Sex allocation and mating structure in the egg parasitoids of the genus Trichogramma (Hymenoptera:Trichogrammatidae)

Martel, Véronique January 2003 (has links)
No description available.
9

Male fitness and optimal sex allocation in Trichogramma evanescens

Lagacé, Martine. January 1998 (has links)
Fitness components of small and large males (emerging respectively from small and large hosts) of Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) were compared in laboratory experiments. These components were the longevity, courtship, mate competition, and daily and lifetime fertilization. Small males were less fit than large males: they had a reduced longevity, took longer to induce female mating behavior, rarely succeeded in mating females when in competition with large males and had lower fertilization capacity; female fertilized by small males oviposited in the first two days of their life only one third of the progeny of daughters mated by large males. The impact of males fitness on optimal sex allocation by females parasitoids was evaluated by measuring the primary and tertiary sex ratios (proportion of males in the progeny) produced by a female T. evanescens when ovipositing in small and large hosts (low and high quality patches). Females of T. evanescens, an arrhenotokous species, have control on the sex ratio of their offspring by regulation of the sperm's access to the egg. Certain combinations of male and female eggs deposited in a host patch result in greater fitness than others. As predicted, females produced a significantly higher proportion of males on the low quality patches. T. evanescens females adjusted the sex ratio allocated to a patch of homogeneous quality and under complete local mate competition to the expected fitness of their sons, as smaller males have a lower fitness and are expected to have low fertilization capacity and therefore fertilize less females. To optimize her fitness gain (the capacity of the individual to transmit its genes), the sex ratio is increased in order to have all daughters mated.
10

Male fitness and optimal sex allocation in Trichogramma evanescens

Lagacé, Martine. January 1998 (has links)
No description available.

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