La Flavescence dorée est une maladie à phytoplasme incurable qui affecte la vigne. Cette pathologie est uniquement transmise de plante à plante par la cicadelle vectrice Scaphoideus titanus. Malgré l'importance de cette maladie, peu d'études ont été menées sur le vecteur. Ce travail de thèse vise à apporter des connaissances sur la biologie et l'écologie de S. titanus mais aussi de manière plus générale sur l'écologie des insectes phytophages. Trois grands thèmes ont été abordés dans ce mémoire : i) les relations entre l'insecte et son environnement à travers l'influence des températures hivernales sur les œufs en diapause, ii) les relations de l'insecte avec sa plante hôte en examinant l'attractivité de cette dernière et le comportement alimentaire du vecteur, iii) les interactions entre congénères par l'étude du comportement d'agrégation des larves. Les résultats obtenus indiquent que 1) des températures froides ne sont pas indispensables à la levée de diapause mais affectent la protandrie en régulant le sex-ratio opérationnel, 2) l'attractivité de la plante hôte est en grande partie liée à sa couleur et il existe des différences de comportement en fonction du stade de développement, 3) les mâles et les femelles n'ont pas le même comportement alimentaire, ce qui pourrait expliquer leur différentes capacités de vection, 4) l'agrégation des larves ne semble pas due à un recrutement actif de leur part et pourrait contribuer à un transfert horizontal de phytoplasme d'insecte à insecte via la plante. A terme, ces connaissances pourront contribuer à l'élaboration de pistes alternatives à la lutte chimique actuelle contre cette cicadelle dans le cadre d'une réduction des intrants. / The Flavescence dorée is an incurable phytoplasma disease of grapevine. This pathology is exclusively transmitted from plant to plant by the leafhopper vector Scaphoideus titanus. Despite the importance of this disease, few studies have been conducted on the vector. This thesis aims to provide knowledge on the biology and ecology of S. titanus but also more broadly on the ecology of phytophagous insects. Three major themes were addressed in this thesis: i) the relationships between the insect and its environment through the influence of winter temperatures on diapausing eggs, ii) the relationships of the insect with its host plant by examining the attractiveness of the plant and the feeding behaviour of the vector, iii) interactions between congeners in the study of the aggregative behaviour of larvae. Our results indicate that 1) cold temperatures are not essential to break the diapause but contribute to protandry through operational sex ratio regulation, 2) the attractiveness of the host plant is largely due to its colour and different instars exhibit differences in behavioural choices, 3) males and females have different feeding behaviour which may explain their different efficiencies at vection, 4) the aggregation of larvae did not seem to result from active recruitment and could contribute to horizontal insect to insect transfer of phytoplasma through the plant. Such knowledge can contribute to the development of alternative S. titanus pest management techniques.

Chez les parasitoïdes, le succès reproducteur n’est pas seulement de permettre une perpétuation de l’espèce il est aussi très important pour la lutte biologique contre les insectes nuisibles. Donc, il est essentiel que la population se développe durablement et produise des descendants fertiles. Au cours de leur vie, à cause de leur petite taille, les parasitoides doivent faire face aux contraintes écologiques (biotiques et abiotiques) qui peuvent agir directement ou indirectement sur l’individu, impliquant des changements morphologiques, physiologiques ou comportementaux qui, à leur tour, affectent la survie et notamment le succès reproducteur d’individus. L’objectif général de cette thèse était de mieux comprendre les conséquences des contraintes écologiques sur la reproduction à partir d’un ectoparasitoide Anisopteromalus calandrae. Nos résultats montrent que la décision de ponte des femelles parasitoïdes est liée à la densité en hôtes qui affecte à la fois la taille des individus et leur fitness avec comme conséquence une augmentation du nombre de mâles dans la descendance. D’autre part, le stress thermique appliqué soit au stade nymphal ou adulte cause des effets négatifs sur la survie et une diminution du stock de spermatozoïdes est également observée. / In parasitoids wasps, reproductive success not only perpetuation of the species, it is also a very important factor for biological control against pests, since it is essential that the population grows and sustainably produce fertile offsprings. During their lives, because of their small size, parasitoids face ecological constraints (both biotic and abiotic) that may affect directly or indirectly the individuals, involving changes in their morphology, physiology or behavior, which in turn, affect the survival and reproductive success. The overall objective of this thesis was to better understand the consequences of the ecological constraints on reproduction in the ectoparasitoid wasp Anisopteromalus calandrae. Our results show that the parasitoid females’ decision to lay eggs is related to the host density that affects both the offspring’s size and fitness, consequently increasing the number of males in the offspring. On the other hand, the thermal stress applied to the pupae or adults had negative effects on survival and decreased the quantity of sperm. Moreover, stressed males are less successful competitors.

Depuis plusieurs années il est devenu essentiel de comprendre le déterminisme sexuel des espèces à fort intérêt économique afin d’optimiser leur production au sein d’écloseries émergentes.L’objectif principal de cette thèse était de mettre en évidence les mécanismes impliqués dans la détermination et la différenciation sexuelle, et notamment du sexe femelle, chez l’huître perlière P. margaritifera, espèce hermaphrodite protandre et espèce clé de la perliculture, la seconde ressource économique pour la Polynésie française. Pour atteindre cet objectif, deux approches ont été menées : une approche transcriptomique visant à étudier les mécanismes moléculaires du déterminisme et de la différenciation sexuelle, et une approche expérimentale visant à comprendre le phénomène de la sexualisation par des forçages environnementaux et hormonaux en s’intéressant plus particulièrement au déterminisme et à la différenciation sexuelle femelle.Dans l’approche transcriptomique, le transcriptome de la gonade de P. margaritifera a été séquencé à partir de plusieurs échantillons gonadiques d’huîtres de sexe mâle et femelle à différents stades de développement. Après le séquençage Illumina et l'assemblage du transcriptome, 70 147 contigs ont été obtenus. L’analyse fonctionnelle de ces 70 147contigs, a permis d’identifier des gènes d’intérêt et ainsi de constituer un catalogue de 87 ARNm codant pour 67 protéines impliquées dans la détermination, la différenciation sexuelle et/ou la gamétogenèse. Ensuite une analyse stricte des données de quantification RNAseq a révélé 1 937 contigs exprimés de manière différentielle entre les catégories histologiques des gonades. À partir de l’analyse de leurs profils d’expression au sein de chaque échantillon, un nouveau modèle de la reproduction de P. margaritifera, basé sur une double approche analytique, eg. histo-moléculaire, a été proposé. Ce modèle révèle notamment que le déterminisme sexuel de P. margaritifera chez l’adulte se produirait durant une phase de régression de la gonade. Considérant ainsi les nouveaux stades définis par ce modèle, 9 gènes biomarqueurs de la voie sexuelle femelle ont pu être identifiés révélant un modèle prédictif de la voie sexuelle basé sur 3 rapports d’expressions de gènes impliquant 2 gènes inconnus pmarg-c43476 et pmarg-c54338 et 2 gènes connus pmarg-foxl2 et pmarg-fem1-like. Ce deuxième modèle suggère fortement l'implication de pmarg-foxl2 et pmarg-fem1-like dans le déterminisme du sexe de P. margaritifera. Dans l’approche expérimentale, deux expérimentations séparées ont été réalisées pour mettre en évidence l’effet i) de plusieurs combinaisons de température et de niveau trophique, et ii) de l’œstradiol-17β administré par injection directe dans la gonade ; sur le sexe, la gamétogenèse et l’expression des neuf gènes biomarqueurs de la voie sexuelle femelle identifiés précédemment. Les résultats ont montré que la condition combinant la température de 28°C et la concentration en algues de 40 000 cellules mL-1 était la plus favorable non seulement à la maturation des gonades mâles et femelles mais aussi au maintien du sexe femelle. Ce serait dans cette condition environnementale qu’il serait possible d’induire un changement de sexe de mâle vers femelle. Dans la seconde expérimentation, il a été clairement démontré que la reproduction de P. margaritifera pouvait être régulée par les hormones œstrogènes. Les résultats montrent un effet négatif de l’œstradiol sur le développement et la différenciation mâle. Enfin les résultats du modèle prédictif de la voie sexuelle de P. margaritifera, suggèrent une programmation génétique du sexe femelle qui toutefois resterait soumise aux conditions environnementales validant ainsi l’hypothèse d’un mode de détermination mixte du sexe chez P. margaritifera. / For several years it has become essential to understand sex determination of species with high economic interest to maximize their production in emerging hatcheries.The main objective of this thesis was to identify the mechanisms involved in sex determination and sex differentiation, and particularly in female sex, in the pearl oyster P. margaritifera, a protandrous hermaphrodite species and the key species of the pearl farming, the second economic resource for French Polynesia. To achieve this goal, two approaches were undertaken: a transcriptomic approach to investigate the molecular mechanisms of sex determinism and sex differentiation, and an experimental approach to understand the phenomenon of sexualization by environmental and hormonal forcing focusing especially on female sex determinism and female sex differentiation.In the transcriptomic approach, the gonad transcriptome of P. margaritifera was sequenced from several samples of male and female oyster gonads at different stages of development. After Illumina sequencing and assembly of the transcriptome, 70,147 contigs were obtained. Functional analysis of these 70,147 contigs identified genes of interest and allowed the constitution of a catalog of 87 mRNAs encoding 67 proteins involved in sex determination, sex differentiation and/or gametogenesis. Then a strict analysis of RNAseq quantification data revealed 1,937 contigs differentially expressed between the histological categories of gonad. From the analysis of their expression profiles in each sample, a new model of reproduction of P. margaritifera, based on dual analytical approach, i.e. histo-molecular, has been proposed. This model shows that sex determination of adult P. margaritifera pearl oysters occur during a regression phase of the gonad. And considering the new stages defined on this model, 9 biomarkers genes of the female sexual pathway have been identified revealing a 3-gene-pair expression ratio based model, which makes it possible to predict the sexual pathway in this hermaphrodite species. This predictive model involves two unknown genes pmarg-c43476 and pmarg-c54338 and 2 known genes pmarg-foxl2 and pmarg-fem1-like, and strongly suggests the involvement of pmarg-foxl2 and pmarg-fem1-like in sex determinism in P. margaritifera.In the experimental approach, two separated experiments were conducted to demonstrate the effect of i) various combinations of temperature and trophic level, and ii) 17β-estradiol administered by direct injection into the gonad; on sex, gametogenesis and expression of the nine biomarkers genes of the female sexual pathway previously identified. The results showed that the condition combining a temperature of 28 °C and a concentration of 40 000 cells of algae mL-1 was the most favorable not only for the maturation of the male and female gonads but also for the maintenance of the female sex. It would be in this environmental condition that it would be possible to induce a sex change from male to female. In the second experiment, it was clearly demonstrated that the reproduction of P. margaritifera could be regulated by estrogen hormones. The results show a negative effect of estradiol on male development and differentiation. Finally the results of the predictive model of the sexual pathway of P. margaritifera, suggest a genetic programming of the female sex, which however remain subject to environmental conditions, thus validating the hypothesis of a mixed sex determinism mode in P. margaritifera.

L’accroissement de la population humaine mondiale a des répercussions majeures, ce n’est donc pas surprenant, compte tenu de la nécessité de nourrir une population grandissante au niveau planétaire, que la production en conchyliculture ait augmenté au cours des dernières décennies. Or, les connaissances acquises concernant les divers facteurs du déterminisme du sexe et du rapport des sexes chez les bivalves sont très limitées et cela pourrait ralentir grandement le taux de production des éleveurs et leur capacité à intervenir si les stocks venaient à diminuer de façon inquiétante. Certains travaux mentionnent que certains facteurs environnementaux, comme la température, auraient un effet sur le rapport des sexes chez une variété de bivalves, incluant la moule bleue commerciale Mytilus edulis, quoiqu’aucune étude n’ait validé cette dernière possibilité. Cela dit, il est possible que l’environnement des adultes puisse aussi affecter le phénotype de la progéniture. En effet, une transmission intergénérationnelle a déjà été identifiée chez Mytilus, mais la possibilité que les conditions des parents affectent le rapport des sexes spécifiquement n’a jamais été abordée. Il est toutefois connu qu’un facteur maternel présent dans l’œuf affecte le sexe de la progéniture et que cette espèce de bivalve a un mode de transmission des mitochondries particulier. Ce mode de transmission appelé « transmission doublement uniparentale » a rendu possible l’identification du sexe chez les embryons. De cette façon, 1938 embryons provenant de 25 croisements artificiels réalisés à trois températures et effectués lors de trois différentes années ont été analysés. Nos analyses mettent en évidence une variation significative dans la proportion de larves femelles entre les années passant de 64 % à 98 %. Dans certains cas, la proportion de femelle varie de 0 à 100 % entre les différents traitements. Même si un effet général sur le rapport des sexes n’était pas significatif, chaque croisement s’est avéré avoir une norme de réaction qui lui est propre face aux 3 différentes températures. Cette étude met en valeur l’effet important de l’environnement sur le déterminisme du sexe chez M. edulis, autant chez les parents que lors du développement des embryons. / The factors affecting sex determination still remain unknown for most bivalve species. Some studies reported that environmental factors, such as temperature, influence sex determination in certain species, and this has been hypothesized also for the blue mussel Mytilus edulis, but not experimentally validated yet. Adult exposure to different environmental conditions during gametogenesis, which occurs seasonally, may also affect offspring phenotype, including sex determination. Intergenerational carryover effects have been reported in bivalves, but the impact of parental exposures on offspring sex determination has not been examined so far. To address these questions, artificial fertilizations were performed on individuals collected in three different years and their embryos and larvae were reared at three different temperatures to specifically test if the environment influence offspring sex ratio through effects on parental developing gametes and/or on developing embryos. We took advantage of the doubly uniparental inheritance of mitochondria in bivalves to determine the sex of the larvae. The analysis of 1938 larvae from 25 crosses revealed that the overall proportion of female larvae was significantly different among years, varying from 64 % to 98 %. While the proportion of female larvae across temperature ranged from 0 to 100 % in some cases, the reaction norms were cross-specific and there were no significant effects of rearing temperature on sex ratio. Taken together, our results suggested that sex determination in M. edulis occur during the gametogenesis according to the genotype of the parents, but could also be changed during the development. More importantly, both processes are strongly affected by environmental conditions.

Amphibian populations are declining world-wide and one of the suggested reasons is environmental pollutants. Studies of long-term effects on the reproductive system in frogs following larval exposure to environmental pollutants are scarce. It is therefore important to develop methods to study developmental reproductive toxicity in amphibians. In this thesis the usefulness of Xenopus tropicalis (the West African clawed frog) as a model species for a test system was investigated. Effects on the reproductive system after larval exposure to the pharmaceuticals ethynylestradiol (EE2) and clotrimazole were evaluated. The susceptibility to EE2 exposure was compared between the model species and a wild species, the European common frog (Rana temporaria). Larval exposure to EE2 caused female-biased sex ratios in both examined frog species, indicating male-to-female sex-reversal. In adult Xenopus tropicalis, male frogs that were not sex-reversed had reduced fertility and decreased amount of mature spermatozoa in the seminiferous tubules. The proportion of frogs with ovaries but lacking oviducts increased with increasing EE2-concentrations. A female frog without oviducts is sterile. The development of ovaries in sex-reversed male frogs was implied to be similar to control females. The combination of a reduced number of males, due to sex-reversal, and impaired fertility could have severe effects on frog populations. Larval exposure to clotrimazole modulated aromatase activity in gonads and brain in Xenopus tropicalis. Brain aromatase activity was decreased at the time for gonadal differentiation and gonadal aromatase activity was increased at metamorphosis. The findings in this thesis indicate that reproduction in wild frogs might be impaired by estrogenic compounds in the environment. The results combined with the short generation time supports the use of Xenopus tropicalis as a model species when evaluating long term effects of endocrine disruptors on the reproductive system in amphibians.

Gaining a good understanding of marine turtle mating systems is fundamental for their effective conservation, yet there are distinct gaps in our knowledge of their breeding ecology and life history, owing largely to the difficulty in observing these highly mobile animals at sea. Whilst multiple mating by females, or polyandry, has been documented in all marine turtle species, the fitness consequences of this behaviour have not been fully investigated. Furthermore, male mating patterns, operational sex ratios and the number of males contributing to breeding populations are poorly understood, impeding accurate assessments of population viability. In this thesis, I use molecular-based parentage analysis to study, in detail, the genetic mating system of two green turtle (Chelonia mydas) populations. In the focal population in northern Cyprus, I show that, despite exhibiting a strongly female-biased hatchling sex ratio and contrary to our expectations, there are at least 1.3 breeding males to every nesting female. I go on to assess the breeding frequency of male turtles in the population and determine that males do not breed annually at this site, demonstrating that the observed relatively equal sex ratio of breeders is not the result of a few males mating every year, but that the number of breeding males in the population is greater than expected. I show that 24% of nesting females in the population produce clutches with multiple paternity, but do not detect any fitness benefits to polyandrous females, and discuss the potential role of sexual conflict in influencing female mating decisions. Finally, I reveal a high frequency of multiple paternity in green turtle clutches on Ascension Island, one of the largest green turtle rookeries in the world, and discuss possible causes of variation in the level of polyandry among marine turtle populations. The results presented here shed new light on aspects of marine turtle mating systems that are challenging to study, and illustrate the value of molecular data, not only in describing mating patterns, but in elucidating aspects of life history and behaviour that would otherwise be very difficult to ascertain.

The boy-to-girl ratio at birth (secondary sex ratio) is around 1.06 in most populations. The sex ratio may be influenced by many factors, such as stress and immunosuppression, age of parents, parity and sex of preceding siblings. The most common human protozoan parasite in developed countries, Toxoplasma gondii (prevalence 20% - 80%), is known to change the behaviour of its intermediate hosts, thereby increasing the probability of transmission to its definitive host (the cat) by predation. The results of our retrospective cohort study suggest that the presence of Toxoplasma gondii, can influence the secondary sex ratio in humans. Depending on the antibody concentration, the probability of the birth of a boy can increase up to a value of 0.72, which means that for every 260 boys born, 100 girls are born to women with the highest concentration of anti-Toxoplasma antibodies. In accordance with results on human subjects, laboratory mice with toxoplasmosis produced a higher sex ratio than controls, in the early phase of latent infection. Our further results showed that mice in the early phase of latent infection exhibited temporarily increased production of interleukin (IL)-12 and decreased production of IL-10. The mice showed decreased production of IL-2 and nitric oxide and decreased proliferation...

Made available in DSpace on 2017-07-21T19:59:59Z (GMT). No. of bitstreams: 1 Diana Cornelio.pdf: 3420425 bytes, checksum: ff1f9eef75ccbe98d2e754cd2215c5c5 (MD5) Previous issue date: 2013-02-08 / Fundação de Amparo a Pesquisa do Estado de São Paulo / Astyanax scabripinnis is a species found in the neotropics, this species forms demes isolated populations in headwater streams. It is taxonomically unresolved, but is presented as an interesting model to study the presence of chromosomal B. The occurrence of these chromosomes in A. scabripinnis may be associated with various environmental factors and population, although little savvy about maintaining parasitic or possible heterotic effects of these chromosomes. The reproductive biology related to the presence of B chromosomes in A. scabripinnis never been addressed. Thus, the object of this study was to investigate whether aspects of the reproductive process, fundamental to the adaptive value may be related to the presence of B chromosomes in A. scabripinnis. Samples were collected quarterly between the years 2012 and 2013 in Campos do Jordao, Sao Paulo, Brazil (22 ° 40 '49.5 "S, 45 ° 23` 31.9 "W) at Stream Farm Lavrinha basin of the Paraíba do Sul. The gonads were classified macroscopically and microscopically second stages of development. Settled seasonally sex ratio of the population in the different samples. We calculated the gonadosomatic ratio (GSR) and the relationship hepatossomática (RHS) separately for females with and without chromosome B. The presence of B chromosomes was confirmed by classical cytogenetic and molecular with the use of chromosome specific probe B constructed by chromosome microdissection and amplification Degenerated Oligonucleotids Primers (DOP-PCR) and subsequent in situ hybridization (FISH). Geometric morphometric analysis were performed separately for males and females with and without the presence of chromosomes B. The results indicate that the sex ratio varied seasonally having an increased number of males compared to females. Hermaphrodite individuals were found at a frequency of 7.7%. The reproductive period is characterized by an atypical reproductive peak during the winter period, beyond the period observed pattern from the spring in September. The presence of B chromosomes has been linked to possible reproductive strategies in different populations studied, especially in relation to energy intake and stages of gonadal development. There morphometric differences both between individuals female and male subjects with and without chromosome B. / Astyanax scabripinnis é uma espécie encontrada na Região Neotropical, essa espécie forma demes populacionais isolados em cabeceiras de riachos. Ela é taxonomicamente mal resolvida, mas se apresenta como interessante modelo para o estudo da presença de cromossomos B. A ocorrência desses cromossomos em A. scabripinnis pode estar associada a diversos fatores ambientais e populacionais, embora seja pouco esclarecido sobre a manutenção parasítica ou possíveis efeitos heteróticos desses cromossomos. A biologia reprodutiva relacionada à presença de cromossomo B em A. scabripinnis nunca foi abordada. Assim, foi objeto deste trabalho investigar se aspectos do processo reprodutivo, fundamental para o valor adaptativo, podem estar relacionados à presença de cromossomos B em A. scabripinnis. As coletas foram realizadas trimestralmente entre os anos de 2012 e 2013 na região de Campos do Jordão, São Paulo, Brasil (22°40`49,5”S, 45°23`31,9” W), no Córrego da Fazenda Lavrinha, bacia do rio Paraíba do Sul. As gônadas foram classificadas macro e microscopicamente segundo estádios de desenvolvimento. Estabeleceu-se sazonalmente a proporção sexual da população nas diferentes amostragens. Foi calculada a relação gonadossomática (RGS) e a relação hepatossomática (RHS) separadamente para fêmeas com e sem cromossomo B. A presença de cromossomos B foi confirmada por meio da citogenética clássica e molecular com o emprego de sonda específica do cromossomo B construída por microdissecção cromossômica e amplificação por Degenerated Oligonucleotids Primers (DOP-PCR) e posterior hibridação fluorescente in situ (FISH). Análises de morfometria geométrica foram realizadas separadamente para fêmeas e machos com e sem a presença de cromossomos B. Os resultados indicam que a proporção sexual variou sazonalmente havendo um aumento do número dos machos em relação às fêmeas. Foram encontrados indivíduos hermafroditas na frequência de 7,7%. O período reprodutivo é caracterizado por um pico de reprodução atípico no período do inverno, além do período padrão observado a partir da primavera no mês de setembro. A presença de cromossomos B foi relacionada a possíveis estratégias reprodutivas distintas na população estudada, especialmente em relação ao aporte energético e estádios de desenvolvimento gonadal. Há diferenças morfométrica tanto entre indivíduos fêmeas e machos como entre indivíduos com e sem cromossomo B.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-07T16:15:43Z No. of bitstreams: 1 Andrea Carla Lira dos Santos.pdf: 1934014 bytes, checksum: e310b95a7aeab6a66aacfa421b42a846 (MD5) / Made available in DSpace on 2017-02-07T16:15:43Z (GMT). No. of bitstreams: 1 Andrea Carla Lira dos Santos.pdf: 1934014 bytes, checksum: e310b95a7aeab6a66aacfa421b42a846 (MD5) Previous issue date: 2012-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The dolphinfish, Coryphaena hippurus, an oceanic pelagic species with circumtropical distribution, is an important fishery resource around the world. The Archipelago of St Peter and St Paul plays an important role in the migratory route of several species of high commercial value, including the dolphinfish. In this context, studies of reproductive biology may help conservation and management of these stocks by providing essential information, such as the size at first sexual maturity and spawning season. In this study, a total of 861 individuals were examined, 811 of which were sexed (279 female and 532 male). Of these, the stage of sexual maturity was identified in 565 specimens. The fork length (FL) of specimens ranged between 27 and 150 cm, with a sex ratio of 1 male to 1.9 females. The distribution of average monthly Gonadal Index of adults ranged between 0.58 and 3.73 for males and between 3.22 and 34.90 for females. Size at first sexual maturity (L50) was estimated at 68.8 cm FL, for males, and 67.7 cm FL, for females. The results suggest that the period of greatest reproductive activity occurs between April and June. / O dourado, Coryphaena hippurus, é uma espécie pelágica e oceânica com distribuição circumtropical, que representa um importante recurso pesqueiro em todo o mundo. O Arquipélago de São Pedro e São Paulo se encontra na rota migratória de várias espécies de elevado valor comercial, entre elas o dourado. Diante desse contexto os estudos de biologia reprodutiva representam uma ferramenta útil para o auxílio da conservação e gestão desses estoques através do aporte de informações, como, por exemplo, tamanho de primeira maturação sexual e época de desova. Nesse trabalho, 861 indivíduos de dourado foram examinados, dos quais 811 foram sexados (279 machos e 532 fêmeas), tendo sido identificados os estágios de maturação gonadal de 565. O comprimento zoológico dos exemplares variou entre 27 e 150 cm, com proporção sexual de 1 macho para 1,9 fêmeas. A distribuição da média mensal do Índice Gonadal dos indivíduos adultos variou entre 0,58 e 3,73 para os machos e entre 3,22 e 34,90 para as fêmeas. O comprimento de primeira maturação sexual (L50) foi estimado em 68,8 cm de Comprimento Zoológico (CZ), para os machos, e 67,7cm de CZ, para as fêmeas. Os resultados sugerem que o período de maior atividade reprodutiva ocorre entre abril e junho.

Made available in DSpace on 2014-07-29T16:24:22Z (GMT). No. of bitstreams: 1 DISSERTACAO FERNANDO G DE ARAUJO.pdf: 269926 bytes, checksum: e1a81ca1614ac2d8e004f83f9641d998 (MD5) Previous issue date: 2009-11-17 / Soybean cyst nematode, Heterodera glycines Ichinohe, is one of the major phytopathological problems affecting the soybean, in the major producing countries of this legume. Eradication of H. glycines from contaminated areas is practically impossible. Thus, the soybean growers have to adapt control measures in order to maintain low population levels. The main control measures are crop rotation, soil management and use of resistant cultivars. With the purpose to evaluate the development of H. glycines and male/female ratio on soybean resistant and susceptible cultivars two trials were conducted during the years 2007 and 2008. Susceptible cultivars BRS Aracu, BRSGO Jatai, BRSGO Luziania, BRS Favorita RR, BRS Valiosa RR, BRS Silvania RR and resistant cultivars BRSGO Ipameri e BRSGO Chapadoes were evaluated. Soybean seedlings were transplanted to pots containing naturally infested soil with H. glycines, race 14, and, 10 days later, part of the plants remained in the pots to evaluate the females, while the other part was removed for hydroponic growth to evaluate the males. In the trial of 2008 the plants were divided in three lots, with the last one having the roots stained to count the juveniles and to evaluate survival rate. Resistant cultivars always maintained a small number of females and males, except for cultivar BRSGO Ipameri that had high countings of males. Only cultivars BRS Favorita RR and BRS Silvania RR had the expected sex ratio 1:1. All other susceptible cultivars had greater number of males than females, with ratios varying from 5:1 to 11:1. Survival rate was nil for both resistant cultivars, and varied from 6.75% to 35.00% for the susceptible cultivars. Regarding the number of cysts in 100 cc of soil the only cultivar that differed significantly from the others was the BRSGO Jatai on experiment conducted in 2007. The number of eggs per cyst varied, in both experiments, and the resistance did not influence the averages found / nematóide de cisto da soja, Heterodera glycines, é um dos principais problemas fitossanitários que afeta a cultura da soja nos principais países produtores desta oleaginosa. A erradicação do H. glycines nas áreas contaminadas é praticamente impossível. Dessa forma, o produtor deve adotar práticas culturais com o intuito de manter baixos os níveis populacionais. As principais medidas de controle são a rotação de culturas, o manejo de solo e a utilização de cultivares resistentes. Com o objetivo de avaliar o desenvolvimento de H. glycines e a proporção macho:fêmea em cultivares de soja resistentes e suscetíveis foram realizados dois experimentos, sendo um em 2007 e outro em 2008. Avaliou-se as cultivares suscetíveis BRSGO Araçu, BRSGO Jataí, BRSGO Luziânia, BRS Favorita RR, BRS Valiosa RR, BRS Silvânia RR e as cultivares resistentes BRSGO Ipameri e BRSGO Chapadões. Plântulas pré-germinadas de soja foram transferidas para vasos com solo naturalmente infestado com H. glycines, raça 14, e, após dez dias, parte das plantas permaneceram nos vasos para avaliação de fêmeas e cistos no solo, e outra parte foi utilizada para instalação do sistema hidropônico para avaliação de machos. No ensaio conduzido em 2008, as plantas foram divididas em três partes sendo a última destinada à coloração de raízes para contagem de juvenis e avaliação da taxa de sobrevivência. As cultivares resistentes sempre mantiveram baixo número de fêmeas e machos com exceção da cultivar BRSGO Ipameri que obteve altos índices de machos. Somente as cultivares BRS Favorita RR e BRS Silvânia RR produziram uma relação macho/fêmea de aproximadamente 1:1. As demais cultivares suscetíveis apresentaram número de machos maior que o de fêmeas com proporções variando de 5:1 a 11:1. A taxa de sobrevivência foi nula para ambas as cultivares resistentes e variou de 6,75% a 35,00% para as cultivares suscetíveis. Com relação ao número de cistos em 100 cm³ de solo, a única cultivar que diferiu significativamente das demais foi a BRSGO Jataí no experimento realizado em 2007. O número de ovos por cisto variou bastante, em ambos os experimentos, sendo que a resistência não influenciou as médias encontradas