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1
Holmes, Michael J. "When does cheating pay? worker reproductive parasitism in honeybees." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12055.
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In all societies, cooperation between members is necessary to allow the society to function smoothly. However, as the interests of individuals rarely overlap completely, all societies contain members that act selfishly at the expense of the greater entity. Thus, policing mechanisms are generally required in order to maintain cohesion within the society. In social insects, conflict between individuals and the society are often reproductive in nature. Kin selection theory predicts that in haplo-diploid, polyandrous species such as honeybees, workers should largely refrain from producing their own offspring, as the workers collectively have higher inclusive fitness if they rear the sons of their mother, the queen. However, opportunities for personal reproduction at the expense of colony-level fitness are often exploited by individual workers, a phenomenon known as worker reproductive parasitism (WRP). This has led to the evolution of worker ‘policing’, in which workers selectively destroy worker-laid eggs that would otherwise be reared at the colony’s expense. In my PhD, I have investigated WRP in both the Western honeybee Apis mellifera, and the Asian hive bee A. cerana. The major theme of my research has been to elucidate the circumstances that afford opportunities for potential reproductive parasites to evade worker policing. This research is significant, as it yields insights into the conflicting selective forces that lead to the formation of societies, the selfish behaviour of the individuals that comprise them and how this behaviour is controlled. These insights are applicable to all social species, including humans.
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Hillegass, Melissa Ann. "SEX-BIASED PARASITISM AND THE REPRODUCTIVE COSTS OF PARASITES IN A SOCIAL AFRICAN GROUND SQUIRREL." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2205.
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Vertebrate males frequently carry higher numbers of parasites than females. This bias in parasite loads could be a consequence of sexual selection. Grouping species are also assumed to be afflicted with larger numbers of parasites than solitary animals and associated costs of this parasitism could vary with group size or structure. I examined sex-biased parasitism and the influence of group size on parasite loads in Cape ground squirrels (Xerus inauris), a highly social species that occurs in the arid regions of southern Africa. Males carried three times as many ectoparasites as females, but females harbored nearly three times more endoparasites than males. Amount of time spent (per hour) autogrooming was similar between males and females, but amount time spent allogrooming by adult female was over eleven times that of adult males. Longer allogrooming of group members could be decreasing the numbers of ectoparasites of group members and ultimately the group. Males infrequently give or receive allogrooming and travel in very large home ranges, potentially increasing their exposure to ectoparasites. However, movement throughout a large home range may result in males foraging in areas with lower densities of fecal pellets, which could explain the lower endoparasite loads observed in males. When I considered the age class of group members, female age classes were similarly parasitized but male age classes were not. Sub-adult males carried similar ectoparasite loads to adult males and similar endoparasite loads to adult females. This result is of particular interest because sub-adult males are becoming scrotal but typically remain in the group until adulthood. Sexual selection does appear to influence parasite loads in this species, and parasite removal or avoidance potentially mitigates individual parasite loads and their associated costs. Parasites can be detrimental to the health, longevity, and reproduction of their hosts, but these costs are rarely quantified. I removed ectoparasites and endoparasites from Cape ground squirrels for three months and evaluated changes in female body mass, reproduction, burrow use, and grooming in response to parasite removal. Female body mass did not increase with parasite removal, but reproductive success (per capita offspring raised to emergence) increased nearly four-fold, while allogrooming by treated females decreased. Since breeding is highest in the late winter dry season when fewer resources are available, the impact of parasites may be highest during this season. Lactation and gestation are the most physiological stressful processes that females undergo, and the dramatic increase in reproductive success in treated females suggests that these females are able to allocate more resources to reproduction than females afflicted with parasites. These results suggest that studies investigating reproduction and fecundity must consider the vulnerability of the host to parasite infection and the potential impact on reproductive success.M.S.
Department of Biology
Sciences
Biology MS
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Deas, Joseph Benjamin Jr. "The Egg Stacking Strategy: Reproductive Plasticity in Response to Egg Parasitism in Mimosestes Amicus." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/293440.
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All organisms live in environments that are variable across space and time. Variation in selection across these environments may lead to the evolution of generalist genotypes that express phenotypic plasticity, in which one genotype can alter their phenotype (e.g., morphology, behavior, physiology) to match changes in environmental conditions, so that they may survive across a range of environments. In many egg-laying organisms that lack parental care, choosing an oviposition site is critical. The egg is an immobile stage of an animal's life cycle and mothers must balance a complex set of risks in deciding where to place their eggs. Because many biotic and abiotic factors are sources of selection on offspring survival, there is an advantage for females to evolve strategies in oviposition site selection to improve survival. This dissertation focuses on phenotypic plasticity in an offspring protection strategy that is triggered by natural enemies. In the seed beetle Mimosestes amicus (Coleoptera: Chrysomelidae: Bruchinae), females lay eggs on the outside of seed pods of legume trees and beetle larvae bore into and develop in the limited and discrete tissue of the seed. While most eggs are laid singly, I documented that beetle females superimpose eggs atop each other ("egg stacking") in response to the presence of egg parasitoids or parasitized eggs. In my first chapter, I investigated whether egg stacking is a strategy for protecting eggs from parasitism. In my second chapter, I examined female responses to variation in the number and dispersion of parasitized eggs on seed pods. Lastly, I investigated whether the intensity of stacking was affected by egg limitation (the risk of depleting her eggs before utilizing all hosts) or time limitation (losing reproductive ability or dying before laying all of her eggs). This study is unique in that it extends life history theory on egg and time costs to explain variation in egg protection behavior. The insights gained from this dissertation provide a foundation upon which we can examine how interactions among trophic levels impact the behavioral decisions made by insects that allow them to increase offspring survival.
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Branson, David Heath. "Reproductive Allocation and Survival in Grasshoppers: Effects of Resource Availability, Grasshopper Density, and Parasitism." DigitalCommons@USU, 2001. https://digitalcommons.usu.edu/etd/6583.
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A major challenge in ecology is to understand intraspecific variation in life histories. Variation in resource availability can lead to differences in reproductive allocation and life histories. Grasshoppers are a good organism for the study of variation in life histories, since they exhibit life history plasticity in response to biotic and environmental factors. An optimality model for grasshoppers was developed that predicts optimal total allocation to reproduction and optimal effort-per-offspring as functions of resource availability and mortality. Relative allocation to reproduction is predicted to increase with resource availability, while relative allocation to survival declines. A resource-based trade-off between egg size and number does not exist, as optimal egg size is predicted to be independent of resource intake. I examined if changes in reproductive allocation and survival of Melanoplus sanguinipes (Fabricus) under a range of resource availabilities fit the predictions of the model. The patterns of reproductive allocation and survival in the field were in qualitative agreement with the predictions.
I examined the importance of density, resources, and parasitism on the life history patterns of grasshoppers. I conducted an experiment to examine if differences in reproductive allocation of M. sanguinipes are primarily explained by exploitative competition. Per capita resource availability explained a significant amount of the variation in reproduction , as expected with exploitative competition. M. sanguinpes grasshoppers appeared to trade off resource allocation to reproduction for that of allocation to survival, because per capita resource availability did not affect survival.
Careful examinations of changes in life history characteristics in response to parasitism are lacking, despite the fact that parasites often influence resource availability for the host. I investigated the effects of a grasshopper ectoparasitic mite on grasshopper reproduction and survival. Mites had small effects on grasshopper survival. As predicted, both species had reduced initial and total reproduction, and completed development of a lower percentage of ovarioles initiated when parasitized. These experiments act to expand our knowledge of life history theory and further our understanding of grasshopper life history variation and population fluctuations.
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Madelaire, Carla Bonetti. "Relação sazonal entre reprodução, imunidade e ocorrência de endoparasitas em anfíbios anuros da Caatinga." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-22012013-152255/.
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A grande maioria das espécies de anfíbios anuros apresenta um padrão de reprodução sazonal, caracterizado nos machos por um pico de andrógenos que desencadeia maturação testicular, bem como manutenção do comportamento sexual. No entanto, os altos níveis de andrógenos podem apresentar um efeito imunossupressor, podendo também aumentar a probabilidade de infecções parasitárias. A Caatinga brasileira é caracterizada por altas temperaturas e chuvas sazonais e imprevisíveis que determinam o padrão reprodutivo e de atividade dos anuros dessa região, algumas espécies como P. diplolister apresentam comportamento de estivação durante a seca, já Rhinella Jimi e R. granulosa permanecem ativos quanto ao forrageamento durante este período. As drásticas variações deste ambiente poderiam acentuar os ajustes fisiológicos apresentados por essas espécies, principalmente para a espécie estivadora. Foram estudadas as inter-relações entre caracteres morfológicos, fisiológicos e parasitológicos dessas três espécies de anuros, em três períodos distintos, (A) durante a temporada reprodutiva, em um período entre dois surtos reprodutivos (período entre chuvas); (B) durante um surto reprodutivo que acompanhou um evento de chuvas e (C) no período da seca. As duas espécies de Rhinella apresentaram evidências de modulações imunológicas de acordo com período, e correlações entre caracteres imunológicos, fisiológicos e número de parasitas. Pleurodema diplolister apresentou padrões imunológicos coerentes com o processo de economia energética durante a estivação, como redução do número de leucócitos totais, com concomitante aumento na contagem de eosinófilos e relação positiva entre intensidade parasitária e contagem total de leucócitos. As três espécies estudadas apresentaram depleção das reservas energéticas durante o período reprodutivo, possivelmente associada à alta demanda energética do comportamento vocal. Também apresentaram padrões similares de maturação testicular, evidenciando que as espécies estudadas possuem um padrão de reprodução oportunista, típico de espécies que ocupam ambientes áridos. As três espécies também apresentaram relação entre parâmetros imunológicos e carga parasitária, no entanto, para esclarecer as relações causais entre esses fatores, são necessários testes adicionais de desafio imunológico, bem como infecção experimental por parasitasMost part of anurans show a seasonal pattern of reproduction, when males display high levels of androgens associated with testicular development and sexual behavior maintenance. However, high androgens levels also can shows an immunosuppressive effect resulting in increased parasitological disease. The semi-arid Caatinga is an environment characterized by high temperatures and unpredictable seasonal rains that determine the breeding season of anurans. During the dry season, Pleurodema diplolister aestivate borrowed, Rhinella granulose and R. jimi remain foraging. Drastic variation in this environment could increase the physiological adjustments displayed by these species, mainly by P. diplolister. The inter-relation between morphological, physiological and parasitological characters was studied in these three anuran species, in three different periods: (A) dry season, (B) during the rainfall, when males are calling, and (C) in the interval between rainfalls, when males are foraging within the reproductive season. The Rhinella species presented evidences of immunological modulations according to the period and correlations between immunological, physiological parameters and number of parasites. Pleurodema diplolister presented immunological patters consistent with the process of energy economy during aestivation, including total leukocyte reduction, along with eosinophil increase and positive relation between total leukocyte and parasite intensity. The three species presented depletion in energy reserves during the breeding season, possibly associated with the high energy demand of vocal behavior. They also presented a similar pattern of testicular development, indicating that these species present opportunistic reproduction pattern, typical of species that occupy arid environments. The studied species also showed correlations between immunological parameters and parasite load, however, to clarify the causal relation between these parameters, additional immunological challenges and experimental parasite infection are necessary
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Eadie, John McAllister. "Alternative reproductive tactics in a precocial bird : the ecology and evolution of brood parasitism in goldeneyes." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29092.
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Facultative brood parasitism is common among waterfowl (Anatidae), but we have limited understanding of the ecological or evolutionary basis for this behaviour. I studied facultative brood parasitism in two species of cavity-nesting ducks, the Barrow's goldeneye (Bucephala islandica) and the common goldeneye (B. clangula). During a four year study in central British Columbia, I used field experiments, observational studies of marked individuals, and simulation models to (i) examine the consequences of brood parasitism to hosts, and (ii) identify the factors that promote and maintain parasitic behaviour.
In order to assess the costs and benefits of brood parasitic behaviour, I first examined proximate influences on reproductive performance of goldeneye females. Variance in reproductive success among females was substantial and some females were consistently more successful than others. Reproductive success was also influenced by breeding experience, time of breeding, and by the availability and quality of nest-sites. Circumstantial evidence suggests that females compete exploitatively and aggressively for nest-sites and brood territories. I argue that such conditions favour the evolution of parasitic reproductive behaviours.
Parasitic egg-laying occurred frequently during the four years of this study; 35% of all nests were parasitized, while 17% of all eggs were parasitic. Parasitism had few deleterious effects on the reproductive success of hosts. On average, parasitized females produced as many of their own young as non-parasitized females, and there was no effect of parasitism on female survival or on the growth and survival of host young. Hatch success was reduced in some host nests when the frequency of parasitism was high, but such levels of parasitism were uncommon. These results suggest that the costs of brood parasitism to precocial hosts are low. My findings do not support recent speculations that hosts benefit from being parasitized.
Goldeneye females exhibited few defences against parasitic intrusions. Females were more likely to desert their nests when clutch sizes were extreme (i.e., > 16 eggs), but desertion rates did not differ significantly between parasitized and non-parasitized nests. I found no evidence that hosts reduce the size of their own clutch when parasitized, contrary to Anders son & Eriksson's (1982) findings for common goldeneyes in Sweden. On some occasions, hosts removed eggs from their nests, but this appeared to be a response to damaged eggs, rather than a defence against parasitism. Finally, females with territories adjacent to their nest sites were parasitized as often as females with non-adjacent territories, indicating that site-specific territoriality in goldeneyes does not serve to guard nests from parasites.
I tested three hypotheses that have been proposed to explain parasitic behaviour. Brood parasites did not attempt to incubate clutches to which they had contributed, even when host females were experimentally removed from those nests. I therefore reject the hypothesis that brood parasitism is an inadvertent consequence of contests among females for the same nest site. In contrast, parasitic behaviour was more frequent in young females, and was strongly related to the availability of nest-sites. These results support the hypothesis that parasitic laying is a conditional strategy pursued by young females when nest-sites are limited. However, other evidence was consistent with the hypothesis that 'parasitic' and 'parental' behaviours are alternative tactics in a mixed strategy. Estimated lifetime reproductive success was nearly identical for the two groups of females, and the relative reproductive success of parasites was negatively frequency-dependent.
A simulation model incorporating the effects of both density-dependence and frequency-dependence resolved this paradox. The model revealed a density threshold below which frequency-dependence effects were negligible, but above which frequency-dependence played a prominent role. I show that results consistent with both hypotheses are possible when the effects of population density are included. Current theories for the evolution of alternative reproductive tactics focus primarily on the frequency-dependent components of fitness and ignore the effects of population density. My results indicate that density-dependence and frequency-dependence can interact in an unanticipated way to maintain alternative nesting tactics in goldeneyes.Science, Faculty of
Zoology, Department of
Graduate
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Burgham, Mark Colin John. "The impact of brood parasitism by the brown-headed cowbird on the reproductive tactics of the yellow warbler." Thesis, University of Ottawa (Canada), 1985. http://hdl.handle.net/10393/5043.
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Cheng, Becky. "The Role of the Dosage Compensation Complex as a Pathway for Spiroplasma to Induce Male Lethality in Drosophila melanogaster." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/cmc_theses/1540.
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Drosophila melanogaster and many other insects harbor intracellular bacterial symbionts that are transmitted vertically from infected host mothers to their offspring. Many of these bacteria alter host reproductive developmental processes in order to increase their transmission success. For example, Spiroplasma, a spirochete that naturally infects D. melanogaster, selectively kills males during mid-embryogenesis while sparing females. Previous studies suggested that Spiroplasma interacts genetically with the male-specific dosage compensation pathway, which causes ~2-fold up-regulation of most genes located on the male’s single X chromosome so that their expression matches the levels found in females who have two Xs. To further test this idea, I used confocal microscopy to visualize dosage compensation complex (DCC) localization and activity in infected as well as uninfected embryos. In the presence of Spiroplasma, the DCC became abnormally mis-localized across the nucleus. This pattern was accompanied by abnormal acetylation of histone H4K16, a mark induced by DCC activity and needed for proper X chromatin remodeling. My results imply that Spiroplasma directly targets the DCC by misdirecting it to uncompensated regions of the genome, an effect that leads to abnormal gene mis-regulation and consequent lethality (work from other members in our group). To further investigate this interaction, we transgenically expressed low levels of MSL-2 in both Spiroplasma infected and uninfected embryos in order to cause ectopic formation of the DCC in the female sex. I found that when infected, female embryos expressing the DCC showed significantly reduced viability in comparison to uninfected transgenic females. This result supports the notion that Spiroplasma uses the DCC in a dominant gain-of-function manner to kill embryos.
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Ferrer, Maza Dolors. "Effects of parasitism on the condition and reproductive capacity of three commercially exploited fish species in the Mediterranean Sea." Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/385347.
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This PhD thesis evaluates the links between parasitism, condition and reproduction of mature female individuals of three of the most captured fish species in the western Mediterranean Sea: European hake, Merluccius merluccius; red mullet, Mullus barbatus, and European anchovy, Engraulis encrasicolus. Indicators of fish energy reserves (total lipid content in liver, muscle and gonads) and reproductive capacity (fecundity and egg quality) were evaluated, as were the prevalence and intensity of infection by metazoan parasites. By evaluating these relationships, this thesis also provides essential data on the health and reproduction of these three fish species, such as the spawning strategy.La present tesi doctoral avalua els vincles entre parasitisme, condició i reproducció en femelles adultes de tres de les espècies més capturades a la Mediterrània occidental: el lluç europeu, Merluccius merluccius; el roger de fang, Mullus barbatus, i el seitó, Engraulis encrasicolus. Amb aquesta finalitat, es varen avaluar els indicadors de les reserves energètiques (contingut total de lípids en el fetge, musculatura i gònades) i la capacitat reproductiva (fecunditat i qualitat de la posta), així com la prevalença i intensitat de la infestació per paràsits metazous.Paral·lelament a l’anàlisi d’aquestes relacions, aquesta tesi també proporciona dades essencials sobre la salut i reproducció d’aquestes tres espècies, com per exemple l’estratègia reproductiva.
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Serrat, Llinàs Alba. "Reproductive and condition status of “cold water” marine fish: new insights from a changing environment." Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/667412.
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Exploited marine fish species with an affinity for cold waters inhabiting close to the warmer edge of their distribution area are exposed to stress caused by fishing and climate change. Three case studies of “cold water species” were selected (Argentina sphyraena, Micromesistius poutassou and Merluccius merluccius) and, in each case, various biological traits – including the factors regulating early oogenesis, reproductive tactics, physical condition, parasitism and energy allocation trade-offs – were examined. Overall, the main findings support the idea that species-specific biological traits and plasticity influence population’s sensitivity and response to external stressors. This thesis contributes to the improvement of egg production estimation methods and to the understanding of fundamental biological mechanisms and their variabilityLes espècies comercials de peixos marins amb preferència per a aigües fredes, que viuen a l’hemisferi nord properes al límit sud de la seva àrea de distribució, es troben en una situació vulnerable degut al canvi climàtic i a la sobrepesca. Aquesta tesi es centra en tres “espècies d’aigua freda”: el moixó (Argentina sphyraena), la maire (Micromesistius poutassou) i el lluç (Merluccius merluccius). Per tal de completar el coneixement sobre les seves característiques reproductives i avaluar el seu estat de salut, es van escollir tres especies d’aigua freda (el moixó, Argentina sphyraena; la maire, Micromesistius poutassou; i el lluç, Merluccius merluccius) i es van examinar diferents trets biològics que comprenen des dels factors que regulen les etapes més inicials de la ovogènesi fins a diverses característiques reproductives, així com l’estat de condició, el parasitisme i els balanços en la distribució de l’energia interna
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Hardy, Ian Charles Wrighton. "Reproductive strategies in parasitic wasps." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46805.
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West, Stuart Andrew. "Reproductive strategies in parasitic Hymenoptera." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309736.
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Engelstaedter, J. "Theoretical aspects of the evolution of reproductive parasites." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1445430/.
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Reproductive parasites are maternally inherited endosymbionts that manipulate the reproduction of their hosts in a way that enhances the transmission of the parasites, but is deleterious to the hosts. In the present thesis, I try to resolve some ques tions concerning the evolution of reproductive parasites and their hosts by means of theoretical modelling, using a variety of approaches including recurrence equations, optimisation, and stochastic modelling. I first study the question: 'Can male-killing bacteria and meiotic drive elements influence each others' spread and equilibrium frequency in a population' and demonstrate they can. Following this, I examine two questions with respect to host evolution. First, can male-killing or Cl-inducing bacteria facilitate the evolution of haplodiploidy I conclude that past work on this has been overoptimistic, but that the process is possible. Second, how does the pres ence of male-killing bacteria affect basic population genetic processes, in particular the interplay between natural selection and random genetic drift I demonstrate that the host population behaves approximately as if only uninfected individuals existed. I then examine two questions in relation to endosymbiont biology. First, what is the impact of mating systems and segregation on the evolution of new Cl-types I propose outbreeding systems as a context where new CI-types can evolve. Second, how can we expect selection to act on two bacterial strains of reproductive parasites in doubly infected hosts with respect to their density Finally, I examine how we expect the incidence of reproductive parasites to vary in time within a host clade, and how the phylogenetic history of the host clade affects the pattern of spread and expected incidence of the parasites. I conclude my thesis with a general overview of what is known about the evolution of reproductive parasites both empirically and theoretically, and outline some promising future avenues of research.
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Carter, Lucy Mary. "Evolutionary ecology of reproductive strategies in malaria parasites." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9910.
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For vector-borne parasites such as malaria, how within- and between-host processes interact to shape transmission is poorly understood. In the host, malaria parasites replicate asexually but for transmission via mosquitoes to occur, specialized sexual stages (gametocytes) must be produced. Once inside the mosquito vector, gametocytes immediately differentiate into male and female gametes, and motile male gametes must swim through the hostile environment of the bloodmeal to find and fertilise female gametes. Despite the central role that gametocytes play in disease transmission, explanations of why parasites adjust gametocyte production in response to in-host factors remain controversial. Furthermore, surprisingly little is known about the mating behaviour of malaria parasites once inside the mosquito. Developing drugs and/or vaccines that prevent transmission by disrupting sexual stages are major goals of biomedicine, but understanding variation in gametocyte investment and male gamete behaviour is key to the success of any intervention. First, I propose that the evolutionary theory developed to explain variation in reproductive effort in multicellular organisms provides a framework to understand gametocyte investment strategies in malaria parasites. I then demonstrate that parasites appear to change their reproductive strategies in response to environmental cues and in a manner consistent with our predictions. Next, I show how digital holographic microscopy can be used to characterise the morphology and motility of male gametes. I then provide evidence for non-random movement of male gametes and that gamete interactions with red blood cells appear to hinder mating success in a bloodmeal. Finally, I discuss the variation in gametocyte differentiation and fertilisation success when exposed to a number of factors implicated in gametocyte activation. The data presented here provides important information on the basic biology of malaria parasite reproductive stages and demonstrates considerable variation in parasite traits and behaviours in response environmental changes; both in the host and in the mosquito vector.
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Pimenta, Jeanne Marie. "Aspects of the reproductive biology of polystomatid monogenean parasites." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265425.
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Bredlau, Justin P. "Evolving Reproductive Isolation in the Parasitic Wasp Genus Cotesia." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5358.
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Parasitic wasps are highly diverse and play a major role in suppression of herbivorous pest populations, but relatively little is known of the mechanisms driving their diversity. Molecular studies indicate that cryptic species complexes resulting from adaptations to specific hosts or host-foodplants may be common. The gregarious endoparasitoid, Cotesia congregata (Braconidae), is a model system for understanding parasitic wasp biology. It is reported to attack at least 15 species of sphingid caterpillars, most of which are plant family specialists. Molecular studies have demonstrated genetic differentiation of two host-foodplant complex sources originating from Manduca sexta on tobacco (MsT) and Ceratomia catalpae on catalpa (CcC). Response to female pheromone and elements of their courtship songs differ. Wasps from both sources mated and produced F1 hybrid offspring in the laboratory; however, 90% of hybrid females resulting from one of the reciprocal crosses failed to produce offspring. I built on this previous work by evaluating an ecological barrier, the evolution of courtship songs within the genus, and patterns of hybrid sterility among four additional host-foodplant complexes, as well as differentiation of their symbiotic bracovirus. Tests of developmental tolerance to nicotine demonstrate that MsT wasps are highly adapted to hosts feeding on tobacco, whereas CcC wasps experience high mortality. Acoustic analysis of courtship songs among host-foodplant sources of C. congregata and eleven additional species of Cotesia demonstrates that songs are species specific and appear to be correlated with genetic relatedness. Cotesia congregata from all sources mated and produced F1 hybrid offspring in the laboratory; however, hybrid females resulting from specific reciprocal crosses failed to produce progeny. Dissections of hybrid females revealed that sterile wasps lacked mature ovaries and functional bracovirus, a symbiotic virus integrated into the wasp genome and necessary to suppress the host immune system. Relative in vivo expression of wasp bracovirus genes differs between MsT and CcC host-foodplant complexes. Cumulatively, these behavioral, ecological, and genetic barriers to reproduction indicate that C. congregata is diverged into two incipient species with limited gene flow, and provides insight into the role of varied reproductive barriers in speciation of parasitic wasps.
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Levron, Céline. "Parasitisme et hyperparasitisme de poissons : études ultrastructurales de la reproduction de quatre digènes et description de deux nouvelles espèces de microsporidies parasites de digènes." Corte, 2004. http://www.theses.fr/2004CORT3082.
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Au niveau de la réserve naturelle des Bouches de Bonifacio (Corse, France), peu d'études sur le parasitisme des poissons ont été réalisées. Les digènes (plathelmintes, trématodes) sont un groupe très important chez les parasites de poissons. L'ultrastructure de quatre d'entre eux a été étudiée : Diphterostomum brusinae (zoogonidae), helicometra fasciata (opecoelidae), monorchis parvus (monorchiidae) et poracanthium furcatum (opecoelidae). D. Brusinae et M. Parvus sont des parasites intestinaux de diplodus annularis (sparidae), H. Fasciata parasite labrus merula (labridae et P. Furcatum parasite mullus surmuletus (mullidae). Lors de l'étude en microscopie électronique à transmission de ces quatre digènes, deux axes de recherches sont abordés. La première partie de ce travail correspond à une étude ultrastructurale de la reproduction (spermiogenèse et spermatozoi͏̈des). Dans la seconde partie, deux nouvelles espèces de microsporidies, parasites de digènes et hyperparasites de poissons, (protistes, microspora) sont décrites. Au cours de la spermiogenèse, différents processus sont mis en évidence. Chez H. Fasciata et M. Parvus, la rotation des flagelles présente un angle particulier de 120°. Un nouvel élément est décrit chez M. Parvus, appelé prolongement centriolaire. P. Furcatum possède une inclusion centriolaire au niveau de l'extrémité postérieure de son centriole. Le spermatozoi͏̈de des quatre espèces suit le modèle général décrit chez les digènes : deux axonèmes de type 9 + "1" caractéristiques des trepaxonemata, un noyau, des mitochondries et des microtubules corticaux. Certains éléments ultrastructuraux permettent de comparer les gamètes mâles : corps épineux, expansion latérale, ornementations externes de la membrane plasmique, nombre de mitochondries. La structure particulière de l'extrémité antérieure du spermatozoi͏̈de de M. Parvus est décrite pour la première fois lors de ce travail. L'étude en microscopie électronique de D. Brusinae et M. Parvus a révélé la présence de deux microsporidies du genre nosema naegeli, 1857. Leurs cycles de développement sont décrits. Ces deux microsporidies se distinguent des autres nosema connues ches les digènes. Elles sont nouvelles et nous proposons de les nommer nosema diphterostomi n. Sp. Et nosema monorchis n. Sp. Du nom générique de leurs hôtes. Les spores de N. Diphterostomi mesurent 2,1 x 1,4 um et ont un filament polaire décrivant 6 à 7 tours. La taille des spores de N. Monorchis est de 3,2 x 2,5 um et elles possèdent un filament polaire qui décrit 16 à 17 tours autour du diplocaryonIn the " Bonifacio Strait Marine Reserve " (Corsica, France), few studies on the parasitism of fishes have been carried out. The Digeneans (Plathelminthes, Trematoda) are a very important group in the parasites of fishes. The ultrastructure of four of them has been studied : Diphterostomum brusinae (Zoogonidae), Helicometra fasciata (Opecoclidae). Monorchis and M. Parvus are intestinal parasites of Diplodus annularis (Sparidae), H. Fasciata parasite Labrus merula (Labridae) and P. Furcatum parasitizes Mullus surmuletus (Mullidae). The first part of this work corresponds to an ultrastructural study of the reproduction (spermiogenesis and spermatozoon). In the second part, two new species of Microsporidia (Protistes, Microspora), parasites of Digeneans and hyperparasites of fishes, are decribes. During spermiogenesis, various processes are highlighted. In H. Fasciata and M. Parvus, the flagellar rotation presents a particular angle of 120ʿ. A new element is describes in M. Parvus, called centriolar extension. P. Furcatum has a centriolar inclusion at the level of the posterior extremity of its centriole. The spermatozoon of the four species follows the general model described in the Digeneans : two axonemes of 9 + "1" pattern of Trepaxonemata, nucleus, mitochondria and cortical microtubules. Some ultrastructural elements are useful tools to compare the males gametes : spine like bodies, lateral expansion, external ornementations of the plasma membrane, number of mitochondria. The particular structure of the anterior extremity of the spermatozoon of M. Parvus is described for the first time in this work. The study in electron microscopy of D. Brusinae and M. Parvus revealed the presence of two Microsporidia of the genus Nosema Naegeli, 1857. Their development cycles are describes. These two Microsporidia are distinguished from other Nosema known in the Digeneans. They are new and we purpose to name them Nosema diphterostomi n. Sp. And Nosema monorchis n. Sp. , after the generic name of their hosts. The spores of N. Diphterostomi measure 2,1 x 1,4 æm and have a polar filament describing 6 to 7 coils. The spores size of N. Monorchis is 3,2 x 2,5 æm and they have a polar filament with 16 to 17 coils around the diplokaryon
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Gauthier, Nathalie. "Étude d'un ectoparasitoïde solitaire Dinarmus basalis Rond (Hym. Pteromalidae) en situation de compétition intra- et interspécifique : activité reproductrice et réponses comportementales." Tours, 1996. http://www.theses.fr/1996TOUR4014.
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Dinarmus basalis est un ectoparasitoïde solitaire se développant sur les stades larvonymphals de coléopteres bruchidae, notamment de Bruchidius Atrolineatus, infeodés aux graines de légumineuses en Afrique de l'Ouest. D. Basalis peut contrôler les effectifs de ces bruchidae dans les stocks de graines de niebe. Au cours du stockage, le nombre de femelles D. Basalis et E. Vuilleti, une espèce sympatrique compétitrice, augmente. Cette situation favorise la compétition intra- et interspécifique au niveau des hôtes disponibles et peut conduire les femelles D. Basalis à superparasiter et multiparasiter. Les capacités de discrimination intraspécifique et interspécifique des femelles ont été démontrées au niveau comportemental et reproducteur. Ainsi, elles pondent préférentiellement sur les hôtes sains, excepté si l'hôte est parasite depuis peu. Lorsque seuls des hôtes parasites sont disponibles, le taux de superparasitisme dépend des chances de survie de l'oeuf pondu. L'évitement du multiparasitisme est d'autant plus marqué que D. Basalis a de faibles chances de gagner la compétition contre E. Vuilleti. La présence de certains hôtes parasites dans l'aire exploitée par une seule femelle induit une diminution significative de sa fécondité et l'apparition du phénomène de résorption ovocytaire. En réponse aux variations de la qualité de l'hôte, la femelle modifie également le taux sexuel de sa descendance. La discrimination intra- et interspécifique de l'hôte est réalisée par les chimiorécepteurs gustatifs portés par l'ovipositeur. Elle s'appuie sur la perception de plusieurs types de marquage présents au niveau de l'hôte et/ou sur la graine. Les stratégies d'exploitation de l'hôte varient avec la présence de conspécifiques. Lorsque la densité de femelles augmente dans le milieu, que les hôtes soient sains ou parasites, la fécondité des femelles présente des variations limitées mais, le taux sexuel de la descendance augmente. La signification adaptative des résultats est discutée en référence aux modèles d'optimal foraging et de local mate competition
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Tempest, Louisa-Jayne. "Parasites and the costs of reproduction in Soay sheep." Thesis, University of Stirling, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720356.
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Birget, Philip Laurent Guillaume. "Evolutionary ecology of parasites : life-history traits, phenotypic plasticity, and reproductive strategies." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/28805.
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Adaptive phenotypic plasticity, the ability of a genotype to give rise to different phenotypes in different environments, evolves to allow organisms to fine-tune their life-history traits according to the varying conditions they encounter during their lives. Reproductive investment - the manner in which organisms divide their resources between survival and reproduction - is well studied in evolutionary ecology because it is a key determinant of fitness. However, whilst plasticity in reproductive effort is well understood for free-living multicellular taxa (such as insects, birds, and mammals), the application of evolutionary theory for plasticity and life history strategies to unicellular parasites and pathogens is lacking. In this thesis, I use empirical and theoretical approaches to uncover how differential resource allocation to non-replicating, sexual stages (gametocytes) versus asexually replicating stages can be harnessed by the rodent malaria parasite Plasmodium chabaudi to maximise its fitness across the often very variable conditions it encounters during infections. Differential allocation between those stages is equivalent to the fundamental life-history trade-off between survival and reproduction because gametocytes are responsible for between-host transmission (i.e. reproduction of the infection) whereas asexual parasites mediate host exploitation and within-host survival. A suite of within-host models reveal that malaria parasites could gain considerable fitness benefits in the face of low levels of drug treatment if they reduce their investment into gametocyte production ("reproductive restraint"), thereby assuring the continuity of the infection and capitalising on opportunities for future transmission. In contrast, high levels of drug treatment typically select parasites to commit all of their resources to gametocyte production ("terminal investment"), to escape a host that does not offer much opportunity for future transmission. My experiments reveal that P. chabaudi increases both its reproductive investment and its asexual replication rate in anaemic hosts (i.e. host that have a low density of red blood cells), suggesting that parasites profit from host anaemia and can afford high investment in gametocytes ("affluent investment"). I also uncover plasticity in a number of traits that underpin asexual replication rate, including invasion preference for different ages of red blood cells, but it is plasticity in the number of progeny (merozoites) per infected cell that is the main contributor to asexual replication rate. My experiments also reveal genetic variance in plasticity of the life-history traits investigated, which has profound implications for their evolution. Furthermore, plastic modification of these traits is associated with minimal costs or constraints, so that parasites can rapidly match life-history traits appropriately to the within-host environment. Severe anaemia is one of the deadliest symptoms of malaria, so observing that virulence and infectiousness increases in anaemic hosts has also fundamental clinical implications. Finally, the empirical and theoretical observations of affluent investment, reproductive restraint and terminal investment match theoretical predictions of how organisms should behave in varying environments, confirming P. chabaudi as a useful model system to test life-history theory.
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Janishevski, Lisa. "Nest parasitism in red-breasted mergansers (Mergus serrator) in New Brunswick." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31244.
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Intraspecific nest parasitism was studied in a group of colonial Red-breasted Mergansers (Mergus serrator) nesting on the Tern Islands of Kouchibouguac National Park in New Brunswick in 1992. Nest parasitism is very common in this colony, and may influence the high rate of nest abandonment observed. Emphasis was placed on determining rates of successful parasitism (i.e. eggs added during the laying period of the hen at that nest), which are evolutionarily significant, and can easily go undetected. Three methods were used to determine if a nest contained egg(s) from another hen: abnormally large clutch size: more than one egg laid per day: and comparisons of DNA fingerprints of the hen versus putative chicks. When eggs were added to a nest during incubation, the nest was also labelled parasitized, but such eggs were not fully incubated (non-term) and thus were not successful. A new method of blood sampling ducklings in pipped eggs was tested and found to have negative effects on survival. As many as 14.8% (13/88) of the ducklings sampled subsequently died. Researchers wishing to use this method should proceed with caution. DNA fingerprinting determined that 50.0% of nests tested (6/12) were successfully parasitized. Two of six parasitized nests would have gone undetected using the other criteria to detect parasitism, thus proving the value of DNA fingerprinting. Of hatched young genetically analyzed, 30.9% (17/55) were parasitic. Nest parasitism appears to be an alternative breeding strategy in this population. Extra-pair copulation, previously unrecorded in this species, was discovered through DNA fingerprinting in two of four nests analyzed.
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Schneider, Maria Victoria. "Modes de reproduction chez le parasitoi͏̈de solitaire Venturia canesces." Lyon 1, 2003. http://www.theses.fr/2003LYO10071.
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Venturia canescens, un parasitoi͏̈de ichneumonidé de chenilles de piralidés, a deux modes de reproduction : arrhénotoque, (mâles haploi͏̈des et femelles diploi͏̈des)) et thélytoque (des femelles vierges engendrent des filles diploi͏̈des). Cette thélytoquie n'est pas l'effet de bactéries symbiotiques. Dans le Sud de la France, les deux modes de reproduction coexistent en sympatrie. La thèse traite des questions soulevées par cette coexistence. Une étude de la distribution géographique et une analyse moléculaire des populations, ont montré l'existence d'un clone thélytoque très répandu. Cependant quelques individus thélytoques sont génétiquement très proches des individus arrhénotoques. Une importante partie de la variabilité chez les thélytoques est due à un flux génique à partir de mâles arrhénotoques. Pour mieux comprendre la coexistence des deux modes de reproduction, différents traits d'histoire de vie et compromis génétiques reflétants des différentes pressions de sélection ont été étudiés.
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Rodrigues, Da hora Riviane. "Stratégies de reproduction et parasitisme social chez la fourmi ponerine ectatomma tuberculatum (olivier)." Paris 13, 2003. http://www.theses.fr/2003PA132016.
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Chez les insectes eusociaux, la colonie est généralement caractérisée par la présence d'un individu reproducteur, la reine, et d'individus généralement stériles, les ouvrières. Cependant, plusieurs espèces montrent d'importantes variations concernant ce mode d'organisation sociale considérée comme typique, comme par exemple la fourmi ponérine Ectatomma tuberculatum (Olivier). Des études de terrain menées au Brésil et au Mexique couplées à des études comportementales et génétiques montrent que cette ponérine est facultativement polygyne et cette stratégie pourrait favoriser le maintien d'E. Tuberculatum en tant qu'espèce dominante. Dans la population mexicaine, des reines microgynes sont associées à des reines normales (macrogynes). Cependant, les microgynes d'E. Tuberculatum reprèsentent en réalité des inquilines, contrairement aux microgynes de l'espèce proche E. Ruidum. L'origine de ces reines parasites serait vraisemblablement favorisée par la polygynie et la microgynie.
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Brockerhoff, Annette Maria. "Comparative studies of the reproductive strategies of New Zealand grapsid crabs (Brachyura : Grapsidae) and the effects of parasites on their reproductive success." Thesis, University of Canterbury. Zoology, 2002. http://hdl.handle.net/10092/1484.
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The reproductive strategies of four intertidal grapsid crabs, Hemigrapsus sexdentatus, H. crenulatus, Cyclograpsus lavauxi, and Helice cressa, were studied in the field and laboratory, with emphasis on mating behaviour, duration of female receptivity, and sperm competition. Mating occurred in all species during the intermoult on the days prior to oviposition, when the gonoporo opercula of females became temporarily mobile. Female Helice crassa mated up to three weeks after oviposition, but in all other species mating typically ceased at egg-laying. Male Hemigrapsus pp. used a female-centered competition strategy in which they searched for and defended receptive females until they laid eggs. In contrast, male C. lavauxi searched for and intercepted receptive females only for the duration of copulation and then pursued other receptive females (a mating system termed encounter rate competition with pure search and interception). Male Helice crassa searched for receptive females in their immediate neighbourhood and mated with them briefly on the substrate or in the burrow after which the female left (a mating system termed encounter rate competition with neighbourhoods of dominance). The mating season was short and highly synchronous for Hemigrapsus exdentatus and Cyclograpsus lavauxi and asynchronous for Hemigrapsus crenulatus and Helice crassa. In the laboratory, the mean duration of receptivity for females housed with three males varied between 4.1 and 12.4 days, and the copulation frequency of females varied before oviposition between 2.1 and 24.3 times (mean) depending on the species. Female Hemigrapsus spp. isolated from males stayed receptive significantly longer than females held continuously with males. This suggests that females are able to control the duration of their receptivity, and therefore the time available for mating, according to the absence or presence of males. The operational sex ratio (OSR) had no effect on the duration of female receptivity, but female Hemigrapsus crenulatus mated more often when several males were competing for access. Therefore, male-male competition increased the number of matings per female and hence sperm competition within the female spermathecae. Larger males mated significantly more often than smaller males in all species. However, male size did not affect ejaculate size, meaning that small and large males transferred similar-sized ejaculates, e.g., in Hemigrapsus spp. Males of the two Hemigrapsus species followed a different strategy of sperm allocation. Male H. crenulatus, which are typically confronted with a high mating frequency of the female and a long, asynchronous mating season, distributed similar-sized ejaculates, irrespective of female size. By contrast, male H. sexdentatus, which experience a comparatively lower risk of sperm competition during a short, synchronised mating season, invested larger ejaculates for larger females than for smaller females. In addition, the size of the first and second ejaculates transferred to a female by a male H. crenulatus were not significantly different, whereas the first was larger than the second for H. sexdentatus. A parasitological survey was undertaken of the four grapsid crabs and the presence, seasonal variation and relationship with host gender and size of parasites determined. Four internal parasites were discovered: Nectonema zealandica n. Sp. (Nematomorpha: Nectonematoidea), portunion sp. (Isopoda: Entoniscidae), Profilicollis novaezelandensis n. sp. and profilicollis antarcticus (Acanthocephala: P olymorphidae). Portunion sp. castrated its female hosts, but not the males thereby creating a more male-biased sex ratio. Males parasitised with portunion sp. were equally successful during male-male competition and the number of matings they achieved. The above findings are important for our current understanding of mating strategies in Grapsidae, which are more diverse than previously thought. Females with a restricted duration of sexual receptivity have some control over their receptive period and can therefore influence the OSR and the extent of male-male competition. As females mated multiple times during their receptive period, sperm competition is a common feature in Grapsidae. However, males employed different tactics in regards to sperm competition such as longer mating duration (e.g., C. lavauxi), high number of matings (Helice crassa), or post-copulatory mate guarding until oviposition (Hemigrapsus spp.).
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Zakikhani, Mahvash. "Plagiorchis elegans in the molluscan intermediate host : infection, susceptibility, growth, reproduction, mortality and cercarial production." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0020/NQ44641.pdf.
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Forster, Ottilie Carolina. "A influência parasitária de helmintos em aspectos reprodutivos de três espécies de anfíbios da RPPN Foz do Rio Aguapeí, município de Castilho, São Paulo, Brasil." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152249.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A referida tese é o resultado de um trabalho que buscou discutir, como tema geral, o impacto que os parasitas podem causar na ecologia de seus hospedeiros. Ela foi divida em dois capítulos: o primeiro capítulo é uma revisão bibliográfica que discute sobre como os parasitas podem influenciar no desempenho reprodutivo de seus hospedeiros; e o segundo capítulo investigou em três espécies de anfíbios anuros (Leptodactylus chaquensis, Leptodactylus podicipinus, e Hypsiboas raniceps), se os indivíduos parasitados por helmintos são acometidos por alterações em aspectos da reprodução. As três espécies de anuros estudadas, não apresentaram evidências que possam ter alguma relação entre a intensidade parasitária de helmintos e caracteres morfológicos associados à reprodução. O que sugere que estas espécies estudadas apresentem respostas imunológicas e/ou adaptações fisiológicas mediante infecção parasitária.
This thesis is the result of a work that sought to discuss, as a general theme, the impact that parasites can have on the ecology of their hosts. It was divided into two chapters: the first chapter is a literature review that discusses how the parasites can influence the reproductive performance of their hosts; and the second chapter investigated in three species of anuran amphibians (Leptodactylus chaquensis, Leptodactylus podicipinus, and Hypsiboas raniceps), if the individuals parasitized by helminths are affected by changes in aspects of reproduction. The three species of anurans studied didn’t present evidence that could have any relation between the parasite intensity of helminths and morphological characters associated to reproduction. This suggests that these species studied present immunological responses and/or physiological adaptations through parasitic infection.
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McCurdy, Dean Gregory. "Impacts of parasites on reproductive behaviour and fitness of the intertidal amphipod Corophium volutator (Pallas)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0028/NQ52327.pdf.
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Mccurdy, Dean Gregory Carleton University Dissertation Biology. "Impacts of parasites on reproductive behaviour and fitness of the intertidal amphidpod Corophium volutator (Pallas)." Ottawa, 1999.
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Wood, Matthew James. "Parasites, reproductive costs and sexual selection : studies of the European blackbird Turdus merula and the great tit Parsus major." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340166.
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Bollache, Loïc. "Sélection sexuelle, parasitisme et patterns d'appariement chez le crustacé amphipode Gammarus pulex." Lyon 1, 2001. http://www.theses.fr/2001LYO10206.
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La biologie de reproduction de Gammarus lupex est caractérisée par une phase de gardiennage précopulatoire couramment analysée comme une stratégie compétitive développée par les mâles afin d'assurer leur reproduction. Une homogamie en fonction de la taille est fréquemment observée lors de cette phase de gardiennage, tel que les grands mâles sont appariés aux grandes femelles, et les mâles d'une taille moindre aux femelles plus petites. Un suivi sur le terrain de plusieurs populations naturelles, complété par des expériences au laboratoire ont permis de préciser le ou les processus responsables de l'homogamie pour la taille chez Gammarus pulex. En confrontant les prédictions propres à chaque hypothèse avec le pattern observé dans les populations naturelles, les hypothèses de contraintes et de disponibilité des partenaires ont pu être réfutées. La sélection sexuelle apparaît désormais comme le processus majeur permettant d'expliquer l'homogamie. Nous avons comparé dans un second temps les effets de deux parasites acanthocéphales, Pomphorhyncus laevis et Polymorphus minutus sur le succès d'appariement des individus des deux sexes chez Gammarus pulex. Le succès d'appariement des mâles et des femelles parasitées s'avère être fortement affecté sur le terrain. Les mâles parasités sont moins compétitifs que les mâles sains, et les femelles infectées moins attractives que les femelles saines, principalement due à une diminution de leur fécondité. Le succès des mâles et des femelles parasités par P. Minutus est plus faible que celui des individus parasités par P. Laevis. Les différences observées entre les deux parasites doivent vraisemblablement être liées à leur impact au niveau de la physiologie de leur hôte intermédiaire, sans que l'on sache encore ce qui, à ce niveau, diffère réellement entre les deux espèces parasitaires.
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Chassain, Chantal. "Reproduction et comportements d'infestation des hôtes chez les trichogrammes : facteurs de variation génétiques et épigénétiques." Lyon 1, 1988. http://www.theses.fr/1988LYO10171.
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Differences au niveau de la fecondite, du sex ratio de la descendance et de la dispersion des infestations compare chez des souches de meme espece mais d'origine geographique differente dans des populations de trichogrammes
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Pineaux, Maxime. "Gènes immunitaires du CMH chez un oiseau monogame : fitness et stratégies de reproduction." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30275.
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Pendant la reproduction, les parents devraient ajuster leurs décisions en fonction des bénéfices qu'ils en tireront. La production de descendants de bonne qualité peut notamment être assurée par le choix d'un partenaire de bonne qualité génétique. Cependant, des contraintes peuvent limiter ce choix et entraîner un appariement sous-optimal, dont les coûts devraient avoir favorisé l'évolution de stratégies compensatoires après l'appariement. Dans cette thèse, je me suis intéressé aux gènes immunitaires du complexe majeur d'histocompatibilité de classe II (CMH-II) et à la consanguinité chez un oiseau marin monogame, la mouette tridactyle (Rissa tridactyla). Tout d'abord, la diversité au niveau du CMH-II des poussins était associée positivement à leur aptitude, mais cela n'était vrai que pour les femelles. En accord avec ces résultats, les parents avec un CMH-II fonctionnellement similaire, qui produisent des poussins peu divers au niveau du CMH-II, surproduisaient des fils, conformément aux attendus de la théorie de l'allocation au sexe. Concernant la consanguinité, elle réduisait la probabilité d'éclosion des œufs lorsque le sperme fécondant était âgé. Comme attendu, les couples consanguins exprimaient des comportements sexuels leur permettant d'éviter la fécondation par du sperme âgé. Dans l'ensemble, cette thèse montre que les parents peuvent ajuster certaines de leurs décisions reproductives en fonction de leur similarité génétique au niveau de gènes fonctionnellement importants et sur l'ensemble du génome, leur permettant ainsi de compenser en partie les coûts d'un appariement sous-optimalParents are expected to adjust their reproductive decisions depending on the future advantages they will gain. These advantages include increased offspring fitness through acquisition of genetic benefits from mates. However, constraints may force individuals to mate with suboptimal partners. The costs of suboptimal pairing should have created selective pressures inducing the evolution of counter strategies. In this thesis, I investigated whether individuals adjust some reproductive post-pairing decisions depending on the prospective genetic characteristics of their offspring, along with the fitness consequences of these genetic characteristics, using a monogamous seabird species, the black-legged kittiwake (Rissa tridactyla). First, I found that chick functional diversity at major histocompatibility complex class II (MHC-II) genes, which play a pivotal role in vertebrate immunity, was positively associated with fitness-related traits in females, but not in males. Accordingly, parents with functionally similar MHC-II, that were more likely to produce chicks with low MHC-II-diversity, overproduced sons, in line with sex allocation theory expectations. Second, I report experimental evidence that genome-wide genetic similarity between mates decreased egg hatchability when the fertilizing sperm was old. In line with our expectations, genetically-similar pairs performed behaviors allowing avoidance of fertilization by old sperm. Overall, this thesis provides evidence that parents flexibly adapt some reproductive decisions in response to within-pair genetic similarity at key functional genes and over the whole genome, thereby partly compensating the detrimental consequences of suboptimal pairing
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Escallon, Herkrath Camilo. "Reproductive physiology, avian malaria, and the cloacal microbiome in tropical Rufous-collared Sparrows (Zonotrichia capensis)." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/77854.
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Life-history strategies are adaptations in behavior, physiology, and anatomy that influence survival and reproductive success. Variation in life-history strategies is often determined by adaptations to environmental conditions and trade-offs with sexually-selected signals. One of the aspects controlling life-history trade-offs is the endocrine system. Testosterone is a hormone that mediates several key aspects of male reproduction, yet little is known about the causes and consequences of variation in testosterone. Using rufous-collared sparrows (Zonotrichia capensis), a Neotropical songbird with a wide distribution, I explored geographical patterns of variation in testosterone levels and infection by haemosporidians, a type of blood parasite. I found that testosterone did not vary with elevation, nor predict haemosporidian infection, but males in breeding condition were more likely to be infected (Chapter I). High levels of testosterone have been associated with an increased number of sexual contacts and can suppress the immune response, thus it may increase the risk of sexually transmitted infections. By studying the communities of bacteria that reside in the cloaca of birds, I found that they were different depending on testosterone levels, and that high-testosterone males had higher relative abundance of Chlamydiae, a class of intracellular pathogens (Chapter II). During the breeding season there is an increase in physical contacts among individuals, testosterone levels increase in males, and there are additional energetic demands, all of which can increase exposure to bacteria or facilitate infection. I compared the cloacal microbiome of the same individuals between breeding and non-breeding seasons, and found that in males, but not in females, bacterial richness and phylogenetic diversity increased when birds were in reproductive condition. This suggested that the cloacal microbiome in birds is dynamic and responsive to breeding condition and sex of the host (Chapter III). Lastly, I synthesized the most relevant findings and suggested directions for future work (Chapter IV). I conclude that variation in testosterone is not always associated with immune suppression, and that the links among reproductive physiology, behavior, and the microbiome can provide insight into the evolution of life-history strategies.Ph. D.
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Kimoro, Charles Omuoyo. "The effects of Plagiorchis noblei, Park, 1936 on the reproductive success and behaviour of adult Aedes aegypti /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59867.
Full textAbstract:
Aedes aegypti pupae were exposed to cercariae of the digenean Plagiorchis noblei in order to assess the effects of infection on the spontaneous flying activity and reproductive success of surviving adults. Infections established primarily in the thorax and abdomen of the insects (mixed infections) or in the abdomen alone. In mixed infections, as few as one or two metacercariae in the thorax reduced the spontaneous flying time of females by almost half. Such infections also reduced total egg production, the number of ovarian cycles, fecundity per cycle, as well as fertility and life span of female hosts. The fertility and life span of males was similarly affected. Purely abdominal infections reduced the life span of males and females as well as the fertility of males, but only at high intensities. Such effects on adult behaviour, reproductive success and life span may augment the known lethal effects of the parasite.
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Bouchard, M'Liki Jovette. "Determining rates of intraspecific nest parasitism in a colony of Red-breasted Mergansers (Mergus serrator) using microsatellite analysis." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32764.
Full textAbstract:
The rate of intraspecific nest parasitism was determined for a colony of Red-breasted Mergansers (Mergus serrator) nesting on the Tern Islands in Kouchibouguac National Park, New Brunswick. In order to recognize instances of nest parasitism, field criteria and microsatellite analysis testing for parentage between attending hens and the eggs in their nests were used. Traditionally, molecular analysis has involved collecting blood samples from females and offspring, however, for the purpose of this study, DNA was extracted successfully from feathers, egg membranes, and unhatched embryos which were collected during the summers of 1999 and 2000. A total of 8 primer pairs which amplified microsatellite loci in closely related avian species were tested (Sfimu-2, Sfimu-3, Sfimu-4, Sfimu-5, Sfimu-6, Sfimu-7, Bcamu-6, and Alamu-1). Four of these primers produced product of the expected size (Sfimu-3, Sfimu-4, Sfimu-7, and Bcamu-6). Amplification of these loci, however was inconsistent and subsequent sequence analysis revealed that the amplicons did not contain tandem repeats and therefore were not useful in genotyping. From field criteria we were able to establish rates of parasitism of 46% and 44% for each season. Rates of parasitism tended to be higher at the beginning of the season, compared to nests initiated later. Field criteria bring support to several hypotheses on causes of nest parasitism, indicating that more than one may influence rates of parasitism in a population.
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Wolf, Maya 1981. "The reproductive ecology of a northeastern Pacific nudibranch, Janolus fuscus, with an examination of its endoparasitic copepod, Ismaila belciki." Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/11057.
Full textAbstract:
xxii, 242 p. : ill. (some col.)The arminacean nudibranch Janolus fuscus (family Zephyrinidae) is found in rocky intertidal habitats along the northeast Pacific coast. Adult J. fuscus are conspicuous from April to October but absent in the early winter at two sites, North Cove and Fossil Pt., in the Coos Bay region of Oregon. Over four years of intertidal surveys at these sites, the density of J. fuscus peaked with the abundance of their bryozoan prey, Bugula pacifica and Tricellaria circumternata , in spring and summer, while adult absence in winter was correlated with strong winter storms. To describe the timing of development and determine the life cycle of J. fuscus , embryos and larvae were reared in the laboratory and examined with light, scanning electron, and confocal microscopy. Larvae reared in the lab and juveniles collected from the field were monitored to quantify growth. Janolus fuscus exhibited typical spiral cleavage and hatched as planktotrophic veligers that grew for over a month before they reached competency, settled, and metamorphosed on their prey, B. pacifica . Juvenile growth was rapid, and adults reached maximum sizes of over 50 mm before dying. These demographic and developmental studies suggest that J. fuscus is a subannual species with a life span of approximately five months. Janolus fuscus is often infected with an endoparasitic copepod, Ismaila belciki . In the field, prevalence of I. belciki increased with host density and size. The distribution of I. belciki was weakly aggregated in the host population. The large female parasite was generally found in the anterior portion of the host hemocoel, and one or more dwarf males were typically associated with each female. Infected J. fuscus produced significantly smaller egg masses with fewer larvae than did uninfected individuals. Infection did not influence growth rate but did cause decreased survival in older nudibranchs. To examine the life cycle of I. belciki , naupliar larvae were reared in the lab and incubated with potential hosts. Additionally, copepodid stages were described from dissected J. fuscus collected from the field. Ismaila belciki has a least three planktotrophic naupliar stages and four copepodid stages in its life cycle.
Committee in charge: Barbara Roy, Chairperson; Craig Young, Advisor; Richard Emlet, Member; Sandra Brooke, Member; Frances White, Outside Member
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Blacher, Pierre. "Coopération, conflits et décisions reproductives individuelles dans les sociétés annuelles de bourdons (Bombus terrestris)." Thesis, Paris 13, 2014. http://www.theses.fr/2014PA132013.
Full textAbstract:
L’existence de conflits est une caractéristique inhérente aux sociétés animales dont la structure génétique est non clonale. L’objectif principal de cette thèse était d’étudier les décisions reproductives individuelles des ouvrières en lien avec la dynamique coopération/conflit dans les sociétés annuelles du bourdon Bombus terrestris. Les colonies de B. terrestris présentent la particularité de se développer selon deux phases distinctes : une phase sociale caractérisée par une coopération altruiste des ouvrières et une phase de compétition durant laquelle les ouvrières entrent en conflit entre elles et avec la reine pour la production des mâles. L’analyse détaillée du comportement de dérive en conditions semi-naturelles a permis de démontrer l’existence d’une stratégie de reproduction supplémentaire pour les ouvrières ; quand le conflit s’exprime, certaines ouvrières fertiles quittent leur nid pour se reproduire dans les colonies voisines de la même espèce. Cette stratégie alternative de reproduction permet aux ouvrières d’éviter l’inhibition reproductive au sein de leur nid et d’optimiser ainsi leur inclusive fitness. Nos études ont de plus révélé que les ouvrières ajustent de façon adaptée leur comportement reproducteur à l’environnement social. La grande plasticité reproductive des ouvrières repose sur leur capacité à détecter et à traiter de multiples informations pertinentes de leur environnement social. Enfin, les résultats de cette thèse suggèrent l’existence d’une stratégie de défense coloniale contre le parasitisme reproductif des ouvrières. De part leur signature chimique spécifique, les parasites potentiels sont reconnus et discriminés comportementalement à l‘entrée du nid par les gardes. Cette pluralité de stratégie de reproduction à la disposition des ouvrières est marginale au sein des hyménoptères sociaux, et les résultats obtenus de ce travail nous conduisent à discuter les traits d’histoire de vie de B. terrestris qui ont pu favoriser leur évolutionConflicts are inherent characteristics of non-clonal animal societies. The main goal of this thesis was to study the individual reproductive decisions of workers in relation with the cooperation/conflict dynamics in the annual bumblebee Bombus terretris. Colonies of B. terretris have the particularity to go through two distinct phases : a social phase characterized by an altruistic cooperation from workers and a competition phase during which the queen and workers compete for the production of males. The study of worker's behaviour in semi-natural conditions allowed to demonstrate the existence of an additional reproductive strategy for workers ; when the conflict is expressed, some fertile workers leave their nest to reproduce in neighbouring colonies of the same species. This alternative reproductive strategy allows workers to avoid reproductive inhibition in their nest and thus to optimize their inclusive fitness. Workers also adjust their reproductive behaviour to their social environment, in line with their reproductive interests. This high reproductive plasticity of workers relies on their ability to detect and process the multiple relevant signals of their social environment. Finally, the results of this thesis suggest the existence of a colonial defence strategy against worker reproductive parasitism. By their specific chemical signature, potential parasites are recognized and behaviourlly discriminated by guards at the nest-entrance. The multiple reproductive strategies of bumble bee workers appear marginal in social Hymenoptera, and the life history traits of B. terretris which could have promoted this diversification are discussed
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Volkoff, Anne-Nathalie. "Recherches de base pour l'élaboration d'un milieu artificiel brut assurant le développement de Trissolcus basalis (Woll. ) (Hymenoptera, Scelionidae), parasitoi͏̈de oophage de Nezara viridula L. (Hemiptera, Pentatomidae)." Toulouse, INPT, 1990. http://www.theses.fr/1990INPT020A.
Full textAbstract:
La recherche d'un milieu artificiel brut pour le parasitoide oophage trissolcus basalis (woll. ) nous a conduit a etudier certains points de sa biologie in vivo. Il s'est avere qu'au cours du developpement embryonnaire, des granules puis des teratocytes sont liberes dans l'hote. Leur role sur le developpement larvaire, qui comprend trois stades, est encore a rechercher. En revanche, le suivi du comportement de ponte a permis de mettre en evidence l'injection par la femelle, avant le depot de l'uf, d'une substance qui agit indirectement sur le developpement preimaginal en modifiant l'organisation et la qualite trophique du vitellus hote. Les tests in vitro ont montre que la presence d'hemolymphe et/ou de vitellus hote est necessaire pour le developpement du parasitoide. Les meilleurs resultats (rendement et duree) ont ete obtenus avec un milieu contenant de l'hemolymphe de manduca sexta et un melange d'acides amines libres, ce qui indique un desequilibre en aminoacides de l'hemolymphe de lepidoptere utilisee. Les seules nymphes obtenues dans un milieu artificiel l'ont ete a partir de l2 agees dissequees de l'hote naturel; des adultes ont pu se former, mais seulement lorsque les l3 etaient a l'air libre. Ces resultats semblent indiquer qu'un facteur nutritionnel propre a l'hote ainsi que les echanges gazeux ont un role sur les processus de nymphose et de formation des adultes
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Mansir, Aïcha. "Le cytosquelette pendant la spermatogenèse des nématodes parasites : actine, protéine spermatique majeure (MSP) et tubuline chez Heligmosomoides polygyrus." Paris, Muséum national d'histoire naturelle, 1998. http://www.theses.fr/1998MNHN0010.
Full textAbstract:
Les spermatozoïdes des nématodes sont caractérisés par l'absence de flagelle et une motilité amiboïde. Selon des études précédentes chez caenorhabditis elegans et ascaris suum, leur motilité n'implique pas l'actine, mais la protéine spermatique majeure (MSP). Nous avons utilisé plusieurs techniques (immunocytochimie, microscopie électronique a transmission et balayage, immunotransfert) pour comprendre la distribution spatio-temporelle des protéines cytosquelettiques pendant la spermatogenèse, principalement l'actine, la MSP et la tubuline, chez heligmosomoides polygyrus. Cette espèce a des cellules germinales males de grande taille et les organites sont aisément identifiables. L'actine et la MSP ont une localisation similaire dans les corps fibreux des spermatides et, paradoxalement, au niveau du capuchon antérieur des spermatozoïdes, zone d'origine des pseudopodes. Nous avons confirmé ces résultats chez trois autres espèces de nématodes. La tubuline forme différentes structures transitoires pendant la spermatogenèse, en particulier un faisceau de microtubules dans les spermatides âgées. Dans ces structures, la présence/absence des modifications post-traductionnelles (tyrosination, detyrosination et polyglutamylation présentes, acétylation et polyglycylation absentes) semble être indépendante du stade de développement. Dans les spermatozoïdes, les seules structures contenant des microtubules sont les deux centrioles, d'une structure aberrante à 10 singulets. Nos résultats précisent le rôle de la tubuline dans la morphogenèse cellulaire et l'arrangement des organites durant la spermatogenèse. L'actine est probablement aussi impliquée dans ces processus. La présence de l'actine dans le capuchon antérieur, avec la MSP, est difficilement compatible avec l'hypothèse d'un fonctionnement indépendant de la MSP
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De, Bruyn Colin. "Modalités fonctionnelles et évolutives des parasitoses développées par les crabes Pinnotheridae aux dépens des échinides fouisseurs." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209978.
Full textAbstract:
Ce travail s’est intéressé aux liens existant entre la stratégie d’exploitation développée par un crustacé ectoparasite et son comportement reproductif. Le crabe Pinnotheridae Dissodactylusprimitivus exploite deux espèces Spatangidae vivant dans la Mer des Caraïbes, Meoma
ventricosa et Plagiobrissus grandis. Des approches comportementales, démographiques et
génétiques ont été adoptées afin de mettre en lumière le fonctionnement et la biologie de cette
symbiose. Par son comportement alimentaire, le crabe occasionne des lésions tégumentaires
sur ses hôtes. Celles-ci affectent la fitness de M. ventricosa, au travers de son développement
gonadique. Dissodactylus primitivus exploite ses deux espèces hôtes de façon asymétrique. La
reproduction des parasites se déroule sur les deux hôtes, alors que le recrutement ne s’effectue
que sur M. ventricosa. Ce cycle vital asymétrique du crabe serait stabilisé par la qualité et la
rareté de P. grandis. En outre, Le comportement sexuel du crabe sur M. ventricosa répondrait
aux critères de la polygynandrie à femelles mobiles. Selon ce modèle, les mâles et les
femelles se déplacent entre les hôtes à la recherche de partenaires multiples. Lors de ces
déplacements, le crabe s’aiderait de son aptitude à localiser chimiquement ses hôtes.
Néanmoins, ce mécanisme s’avère plastique et pourrait refléter l’asymétrie du cycle vital. En
effet, cette différence n’a pas d’origine génétique, car les crabes vivant au sein du site d’étude constituent la même population quelle que soit l’espèce hôte considérée. Les marqueurs
moléculaires microsatellites mis au point dans ce travail permettront lors de futurs travaux
d’affiner les observations sur les modalités d’accouplement du crabe et d’estimer sa capacité
de dispersion.
This work aimed to highlight the relationships between the host exploitation strategy of an
ectoparasite crustacean and its mating system. The pea crab Dissodactylus primitivus exploits
two Spatangidae species living in the Caribbean Sea, Meoma ventricosa and Plagiobrissus
grandis. Behavioural, demographic and genetic approaches have been conducted to examine
the functioning and biology of this symbiosis. Owing to its feeding behaviour, the crab
wounds the host tegument. The wounds negatively affect M. ventricosa's fitness through its
gonadic development. Dissodactylus primitivus asymmetrically exploits its two host species.
The reproduction of the parasites happens on each host, but the recruitment only takes place
on M. ventricosa. The asymmetrical life cycle would be stabilised par the quality and the
scarcity of P. grandis. The mating system of crabs living on M. ventricosa would correspond
to the Pure-search polygynandry of mobile females criteria. According to this model, the
males and the females practice the host switching behaviour to find several sexual partners.
During these movements, the crab could use its chemodetection ability to locate its hosts.
However, this mechanism is plastic and presumably reflects the asymmetrical life cycle of the
crab. This difference has indeed not a genetic cause because the crabs living inside the
investigated region belong to the same population, whatever the regarded host species. In
future studies, the microsatellites markers developed for this work could be used to test the
mating system of D. primitivus and to estimate its dispersion ability.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Lacoume, Sandrine. "Développement et succès reproducteur des mâles parasitoïdes, Dinarmus basalis, suite à des contraintes environnementales." Tours, 2007. http://www.theses.fr/2007TOUR4009.
Full textAbstract:
Les mâles doivent préserver leur potentiel de fertilisation en dépit de contraintes environnementales. Le but de cette thèse est de déterminer l’influence de la ressource hôte et d’un choc froid sur la fitness d’un mâle hyménoptère parasitoïde Dinarmus basalis. Nos résultats ont montré qu’un choc froid appliqué sur un mâle adulte n’affecte pas son potentiel de reproduction. A l’inverse ce choc appliqué durant le développement entraîne une réduction du nombre d’individus émergents, sans altérer la durée de développement. Un résultat semblable est obtenu lors d’une contrainte alimentaire. Celle-ci affecte également le phénotype des mâles en réduisant leur taille corporelle et celle de leur tractus génital. Dans les deux cas, nous avons constaté une réduction de la quantité de spermatozoïdes. Les mâles ayant subi un stress durant leur développement sont capables de s’accoupler, mais sont désavantagés lors de compétitions entre mâles et lors d’accouplements répétésMales should protect their sperm stock and fertilization potential. The aim of this thesis is to investigate the effects of different environmental constraints on the reproductive success of males of the hymenoptera parasitoid, Dinarmus basalis. We have chosen a biotic factor (host resource) and an abiotic factor (a cold shock). Our results show that a cold choc on adult males does not affect their reproductive potential. However, a cold shock applied during development reduces males’ emergence but not developmental durations. Similar results are obtained with a dietary constraint applied during male development. This constraint affects also male phenotype by reducing both male and genital tract size. A stress applied during development reduces the quantity of sperm. In single mating, these constraints do not prevent male from mating. However, in repeated mating and male-male competition, constraints applied during development disadvantage males
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Platero, Idalia Ada. "The effects of parasite dose, host size and method of exposure on the reproductive capacity and survival of Biomphalaria glabrata infected with the incompatible digenean, Plagiorchis elegans /." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80350.
Full textAbstract:
The digenean parasite, Plagiorchis elegans can establish infections in the incompatible snail, Biomphalaria glabrata , a vector of human schistosomiasis. Although embryonic development is arrested at the sporocyst stage, infection with a single parasite egg reduced reproductive success of this incompatible host to 64%. Heavier doses reduced this to 45%. Biomphalaria glabrata quickly acquired large numbers of parasites by ad libitum browsing on egg-contaminated substrates. Age of the host at exposure affected subsequent reproductive success and survival. Snails exposed as young (3mm), produced 54% fewer eggs, and suffered relatively high mortality. Adults (9mm) were affected only marginally. Plagiorchis elegans shares its ability to establish truncated infections in incompatible hosts with at least one other plagiorchiid. Haematoloechus medioplexus castrated the snail Stagnicola elodes, but not B. glabrata. Findings are discussed in the context of using incompatible digenean parasites as agents in the biological control of snails and snail-borne diseases, and ecological consequences of these infections.
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Matos, Dilânia Lopes de. "Reação de genótipos de arroz de terras altas a Meloidogyne javanica." Universidade Federal de Mato Grosso, 2014. http://ri.ufmt.br/handle/1/622.
Full textAbstract:
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CAPES
Nematoides do gênero Meloidogyne, constituem-se em importante grupo de fitoparasitas causadores de danos em culturas de grande importância econômica. Este trabalho teve como objetivo avaliar a reação de genótipos de arroz de altas a M. javanica, realizado em condições de casa de vegetação. Foram utilizados genótipos de arroz de terras altas, oriundos do programa de melhoramento genético da Embrapa Arroz e Feijão. O delineamento experimental utilizado foi o inteiramente casualizado com 37 tratamentos, sendo 36 genótipos de arroz e uma cultivar de soja (BRSMG 760RR) utilizada como testemunha suscetível, em quatro repetições cada. A população de nematoide das galhas foi mantida em plantas de tomateiro. As plantas de arroz foram inoculadas com 1000 ovos + juvenil segundo estádio (J2), 30 dias após semeadura. Aos 60 dias após inoculação, foram avaliadas as seguintes variáveis: Massa Fresca da Raiz (MFR), massa fresca e seca da parte aérea, número de massa de ovos, número de ovos + J2 por sistema radicular, para determinação do índice de massa de ovos (IMO) e fator de reprodução (FR). Foi verificado os coeficientes de correlação linear entre as variáveis IMO x FR, IMO x MFR e MFR x Pf. Os resultados obtidos indicaram que 72% dos genótipos de arroz destacaram-se positivamente, com comportamento de resistência a M. javanica. Verificou-se que nem sempre uma maior população de nematoides no sistema radicular, indica menor massa de raiz e área foliar. Além disso, a avaliação somente do índice de massa de ovos não é suficiente para determinação de resistência ou suscetibilidade a M. javanica de genótipos de arroz, sendo necessário avaliar o fator reprodução. Todas as correlações foram significativas e positivas, indicando que o comportamento dos parâmetros avaliados foi sempre no mesmo sentido.
Nematodes of the genus Meloidogyne, constitute an important group of plant parasites that cause damage to crops of economic importance. This study aimed to evaluate the resistance of upland rice genotypes to M. javanica, conducted in a greenhouse. Were used genotypic materials upland rice, originating from the breeding program of Embrapa Arroz e Feijão. The experimental design was completely randomized with 37 treatments and 36 genotypes of rice and cultivar soybean (BRSMG 760RR) as susceptible, and four replications each. The root-knot nematode populations were maintained on tomato plants, tobacco and soybeans. The rice plants were inoculated with 1000 eggs + second-stage juvenile (J2), 30 days after sowing. After 60 days inoculation the following variables were evaluated: fresh root mass (MFR), fresh and dry weight of shoots, number of egg mass, number of eggs + J2 per root system, for determining mass index eggs (IMO) and reproduction factor (FR), obtained by dividing the final population (Pf) and initial (Pi) of the nematode (FR = Pf / Pi). Was found the coefficient of linear correlation between the variables IMO x FR, IMO x MFR e MFR x Pf. The results indicated that 72% of the xiii genotypes of rice stood out positively with resistance the M. javanica, it was found that a larger population of nematodes in root, does not indicate lower root mass and leaf area. Furthermore, only mass index egg is not sufficient to determine the resistance or susceptibility of rice genotypes the M. javanica, being necessary to evaluate the reproduction factor. All correlations were significant and positive, indicating that the behavior of the evaluated parameters was always in the same direction.
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Ndiaye, Papa Ibnou. "Systématique et Phylogénie de Plathelminthes parasites ("Trematoda et Cestoda"): apport des études ultrastructurales de la reproduction." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/2417.
Full textAbstract:
El presente estudio constituye una importante contribución al conocimiento de la ultraestructura de la espermiogénesis y del espermatozoide de los Platelmintos parásitos. Los caracteres ultraestructurales de la reproducción, particularmente los del espermatozoide, son de gran utilidad para la Sistemática, la Taxonomía y la Filogenia de diversos grupos zoológicos, entre ellos el de los Platelmintos. Por ello, se ha estudiado ultraestructuralmente la espermiogénesis y el espermatozoide de siete especies de Platelmintos parásitos de distintas familias: cuatro Digénidos [Scaphiostomum palaearcticum Mas-Coma, Esteban et Valero, 1986 (Brachylaimidae), Fasciola hepatica, Linnaeus, 1758 y Fasiola gigantica Cobbold, 1856 (Fasciolidae) y Notocotylus neyrai González Castro, 1945 (Notocotylidae)] y tres Cestodos Cyclophyllidea [Joyeuxiella pasqualei (Diamare, 1893) y Joyeuxiella echinorhynchoides (Sonsino, 1899) (Dipylidiidae) y Taenia parva Baer, 1926 (Taeniidae)].Los helmintos, aislados tras disección de los hospedadores, han sido procesados según la metodología pertinente para los estudios ultraestructurales a que van encaminados. En el caso de F. gigantica se ha aplicado la técnica citoquímica de Thiéry para evidenciar la presencia de glucógeno en el gameto masculino. En el estudio de F. hepatica, dada la procedencia del material de la rata negra (Rattus rattus), hemos podido diseccionar el hospedador en el laboratorio y aplicar más fácilmente otras técnicas como son: 1) las técnicas inmunocitoquímicas para evidenciar la tubulina en el citoesqueleto del espermatozoide y 2) las de "whole mount" y de microscopía electrónica de barrido destinadas a la observación de espermatozoides enteros. Las técnicas inmunocitoquímicas de inmunomarcaje ultraestructural nos han permitido de detectar la presencia de las tubulinas contenidas en el citoesqueleto del espermatozoide mediante la utilización de anticuerpos monoclonales (anti-alfa-tubulina, anti-beta-tubulina, anti-tubulina acetilada y anti-tubulina tirosinada).
Los resultados obtenidos en relación las especies estudiadas forman parte de las seis publicaciones expuestas en la Memoria.
El estudio de S. palaearcticum es el cuarto trabajo realizado sobre la ultraestructura del gameto masculino en la familia Brachylaimidae y el primero de la subfamilia Ityogoniminae. En el caso de N. neyrai, el presente estudio constituye la primera aportación ultraestructural para la familia Notocotylidae. En la familia Fasciolidae se ha realizado un estudio comparado de la ultraestructura de la espermiogénesis y del espermatozoide de F. hepatica (parásito de Bos taurus en España y de Rattus rattus en Córcega) con la de F. gigantica (parásito de Bos indicus en Senegal). Para el género Joyeuxiella y, por extensión, para la familia Dipylidiidae, se establece el modelo general de la espermiogénesis y del espermatozoide dada la existencia de datos en dos de los tres géneros incluidos en esta familia. En el caso de T. parva, los resultados aportados contribuyen a la determinación de las características ultraestructurales del espermatozoide para las especies de la familia Taeniidae.
Se efectua una completa revisión y discusión al respecto de diversos caracteres ultraestructurales del espermatozoide de los Digénidos, como son las ornamentaciones externas de la membrana y los cuerpos espinosos. Por otra parte, se describe la formación de una expansión citoplasmática dorso-lateral en el transcurso de la espermiogénesis en F. gigantica y F. hepatica. En el caso de los Cestodos, se describe por primera vez la formación de la vaina periaxonemal durante la espermiogénesis de Joyeuxiella spp. Además, ciertos caracteres de la espermiogénesis de los Digénidos y de los Cestodos primitivos como son la presencia de raíces estriadas y de rotación flagelar son igualmente observados respectivamente en los Cyclophyllidea Joyeuxiella spp. y T. parva.
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Trouvé, Sandrine. "Evolution des stratégies de la reproduction et des traits d'histoire de vie chez les plathelminthes parasites." Perpignan, 1997. http://www.theses.fr/1997PERP0284.
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Les strategies de la reproduction et les echanges genetiques d'un plathelminthe, trematode parasite hermaphrodite, ont ete etudies. L'approche experimentale a ete developpee sur 3 isolats geographiques de l'echinostome echinostoma caproni. Nous montrons que cette espece presente un mode de reproduction mixte associant a la fois de l'autofecondation et de l'allofecondation. Toutes les possibilites de fecondation entre individus d'origines geographiques differentes sont possibles allant jusqu'a des fecondations multiples ; cependant une tendance marquee vers des croisements preferentiels intra-isolats a ete mise en evidence. Cet isolement reproducteur prezygotique etant potentiellement lie a une communication chimique entre individus, nous avons analyse les produits excretes-secretes par les individus de chaque isolat. Nous mettons en evidence que ces produits excretes-secretes presentent, effectivement, des differences caracteristiques de chaque isolat. Une depression hybride a egalement ete observee entre les isolats, ce qui revele l'existence de mecanismes d'isolement reproducteurs postzygotiques. L'utilisation de differentes strategies de reproduction par cet echinostome nous a conduits a tester la prediction de charnov concernant l'allocation des ressources a la reproduction. Conformement a cette hypothese, nous montrons une augmentation de l'investissement energetique dans la fonction male et une diminution de l'investissement dans la fonction femelle lorsque la quantite de partenaire augmente. Enfin, une reflexion generale sur les strategies reproductives nous a conduits a tester l'hypothese selon laquelle l'evolution des traits d'histoire de vie des organismes dependrait de leur mode de vie, libre ou parasite. Une recherche bibliographique nous a permis d'elaborer une base de donnees pour les plathelminthes libres et parasites. En contradiction avec l'hypothese les correlations obtenues apparaissent similaires pour les organismes libres et parasites.
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Vaitilingon, Devarajen. "The biology and ecology of the echinoid Tripneustes gratilla (Linneaus, 1758) off Toliara (Madagascar) :feeding, reproduction, larval development, population dynamics and parasitism." Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211163.
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SILVA, Arinaldo Pereira. "Comportamento de variedades de cana-de-açúcar ao parasitismo de Meloidogyne incognita e M. enterolobii." Universidade Federal Rural de Pernambuco, 2012. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6424.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
The development of resistant varieties is one of the most important alternative for rot-knot management on sugarcane fields. The present work had as objective to evaluate the development of the sugarcane varieties RB92579, RB93509, RB867515 and SP81–3250 under different densities of M. incognita and M. enterolobii, as well the genotypes effect on nematode reproduction, under greenhouse. One month old plants had the soil infested with increasing inoculum densities (0, 5000, 10000 and 20000eggs and juveniles per plant), in a completely randomized design, with evaluations 90 days after. The RB varieties presented higher fresh shoots biomass weight than SP813250 when parasited by M. enterolobii. Meloidogyne enterolobii had the life cycle completed in RB863129, SP813250 and RB867515, in contrast to RB92579. In relation to M. incognita, RB92579 stood out presenting the highest height, stalk number, stalk diameter and fresh root biomass weight. RB863129 presented lower gall index than the other varieties and lower number of eggs per root than RB867515 and SP813250. SP813250 showed the lowest stalk diameter and number, the lowest number of shoot and fresh root biomass and the highest number of eggs per plant. Plant growth was not affect by inoculum density of M. incognita or M. enterolobii. Inversely to M. enterolobii, plants parasited by M. incognita presented gall index higher than 3 and high reproduction factors. No models fitted either M. incognita or M. enterolobii population density to evaluated variables.
O desenvolvimento de variedades resistentes constitui uma das principais alternativas para o manejo dos nematoides formadores de galhas em cana-de-açúcar. O presente trabalho teve como objetivo avaliar o desenvolvimento das variedades, RB92-579, RB93-509, RB86-7515 e SP81–3250 sob diferentes densidades de M. incognita e M. enterolobii, e o efeito dos genótipos sobre a reprodução dos nematoides, em condições de casa de vegetação. Plantas com um mês de cultivo, tiveram o solo infestado com crescentes densidades de inoculo (0, 5000, 10000 e 20000 ovos e juvenis por planta) e foram avaliados ao 90 dias em delineamento inteiramente casualizado. As variedades RB apresentaram maior peso da biomassa fresca da parte aérea do que SP81-3250 quando parasitadas por M. enterolobii. RB86-3129, SP81-3250 e RB86-7515 garantiram o ciclo de vida de M. enterolobbi, enquanto que RB92579, não permitiu o seu completo desenvolvimento. Em relação a M. incognita, a variedade RB92-579 destacou-se das demais por apresentar significativamente maior altura do que RB86-3129 e RB86-7515, maior diâmetro do colmo que RB86-7515, maior número de colmos, número de perfilho e peso da biomassa fresca da parte aérea do que RB86-7515. RB86-3129 apresentou menor número e índice de galhas que as demais variedades e menor número de ovos por sistema radicular do que RB86-7515 e SP81-3250. SP81-3250 apresentou menor diâmetro e número de colmo, menor número de perfilho, menor biomassa fresca da raiz e maior número de ovos por planta. O desenvolvimento das plantas parasitadas por M. incognita ou M. enterolobii não foi afetado pela densidade de inoculo. No entanto, ao contrário de M. enterolobii, as plantas parasitadas por M. incognita apresentaram índices de galhas superiores a três e altos fatores de reprodução. Nenhum dos modelos testados descreveu significativamente as relações entre as variáveis analisadas e as densidades populacionais de M. incognita ou M. enterolobii.
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Doli, Valentin. "Phénomènes de propagation de champignons parasites de plantes par couplage de diffusion spatiale et de reproduction sexuée." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S139/document.
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On considère des organismes qui mixent reproduction sexuée et asexuée, dans une situation où la reproduction sexuée fait intervenir à la fois de la dispersion spatiale et de la limitation d'appariement. Nous proposons un modèle qui implique deux équations couplées, la première étant une équation différentielle ordinaire de type logistique, la seconde étant une équation de réaction-diffusion. Grâce à des valeurs réalistes des différents coefficients, il s'avère que la deuxième équation fait intervenir une échelle de temps rapide, alors que la première fait intervenir une échelle de temps lente. Dans un premier temps, on montre l'existence et l'unicité de solutions au système original. Dans un second temps, dans la limite où l'échelle de temps rapide est considérée infiniment rapide, on montre la convergence vers une dynamique réduite d'état d'équilibre, dont les termes correctifs peuvent être calculés à tout ordre. Troisièmement, en utilisant des propriétés de monotonie de notre système coopératif, on montre l'existence d'ondes progressives dans une région particulière de l'espace des paramètres (cas monostable)We consider organisms that mix sexual and asexual reproduction, in a situation where sexual reproduction involves both spatial dispersion and mate finding limitation. We propose a model that involves two coupled equations, the first one being an ordinary differential equation of logistic type, the second one being a reaction diffusion equation. According to realistic values of the various coefficients, the second equation turns out to involve a fast time scale, while the first one involves a separated slow time scale. First we show existence and uniqueness of solutions to the original system. Second, in the limit where the fast time scale is considered infinitely fast, we show the convergence towards a reduced quasi steady state dynamics, whose correctors can be computed at any order. Third, using monotonicity properties of our cooperative system, we show the existence of traveling wave solutions in a particular region of the parameter space (monostable case)
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Duron, Olivier. "Évolution des parasites de la reproduction : étude des "Wolbachia" responsables des incompatibilités cytoplasmiques chez le moustique "Culex pipiens"." Montpellier 2, 2005. http://www.theses.fr/2005MON20149.
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Rossanigo, Carlos Esteban. "Rôle de l'eau et de la température sur les taux de développement des nématodes parasites du tractus digestif des ruminants." Montpellier 2, 1992. http://www.theses.fr/1992MON20293.
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Les conditions climatiques ont un role preponderant sur la repartition geographique et temporelle des differentes especes de nematodes parasites des ruminants. Sur un exemple tire du parasitisme des bovins du centre-ouest d'argentine, temperature et pluviometrie contribuent a expliquer les niveaux d'infestation par les principaux genres. Un travail plus experimental est developpe en vue d'estimer le role de l'eau a proximite immediate des ufs et jeunes larves des nematodes (dans les feces), avec ou sans celui de la temperature, sur la partie du cycle de developpement allant de l'uf a la larve infestante. Par des depots de feces d'animaux parasites dans des situations climatiques diversifiees, il est montre que la temperature au sein des bouses etait le premier facteur conditionnant le taux de developpement des especes parasitant les bovins et que c'etait l'humidite ponderale des feces dans le cas des parasites d'ovin. Les exigences thermique et surtout hydriques sont definies au laboratoire pour huit especes parasites de bovins, ovins et cervides multipliees sur ovin. L'adaptation aux faibles humidites etait le principal caractere specifique. La taille des larves infestantes s'est averee dependre des conditions de developpement. Par des tests de laboratoire, il est montre que les petites larves developpees a des humidites faibles migraient et se degainaient plus lentement que les normales et semblaient avoir plus de mal a s'etablir chez l'hote. L'adaptation genetique aux conditions seches d'une lignee a ete tentee par une selection pendant 5 generations mais n'a pas revele d'evolution du taux de developpement dans ces conditions