The objectives of the study were to determine whether or not behaviour could be used to predict spawning in Amphiprion akallopisos, and to document the behaviour of this species under various environmental conditions in captivity. The spawning behaviour of A. akallopisos was studied and quantified. Three behaviour patterns - belly touching, nest cleaning by the female and mutual nest cleaning (by the male and the female) were identified as predictors for spawning. The reproductive behaviour of A.akallopisos under three photoperiods was investigated. The photoperiods were: 14L:10D, 10hr15minL:13hr45minD and a natural photoperiod cycle condensed into three months. A. akallopisos maintained under 14 L:10D exhibited a significantly higher frequency and duration of chasing, nest cleaning and total interaction compared to fish kept under 10hr15minL:13hr45minD. A photoperiod of 14L:10D was selected for further studies. As manipulation of photoperiod did not induce spawning, GnRHa was administered to the fish in the diet at levels of 10, 20, 40 and 80 μg/kg BW. Control groups were fed untreated food. None of the dosages were successful in inducing spawning, or spawning behaviour in A. akallopisos. It is possible that the method of hormone application was not suitable for this species. It is also possible that behaviour may regulate blood hormone levels as opposed to endocrine status influencing behaviour. In the third trial, A. akallopisos was maintained with, and without sea anemones in order to determine whether or not anemone hosts are necessary for spawning. The presence of anemones did not induce spawning and A. akallopisos kept without anemones exhibited significantly more interactive behaviour than fish kept with hosts. Spawning of A. akallopisos at a later date without anemones suggests that anemones are not necessary for spawning in A. akallopisos. Light intensity was investigated as a cue for spawning. The reproductive behaviour of A. akallopisos was then studied under light intensities of 4.16 x 10¹⁵ quanta.sec⁻¹.cm⁻², 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻² and this intensity plus natural light. Spawning occurred mainly under 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻². Fish maintained under this light intensity exhibited significantly more of nest cleaning behaviour in terms of frequency and duration than fish maintained under low light intensity. A minimum light intensity of 8.85 x 10¹⁵ quanta. sec⁻¹.cm⁻² is recommended for conditioning of this species. This study can be of practical relevance to hatchery managers who can use the methods developed and record predictors for spawning in A. akallopisos and other Amphiprion species. In this way imminence of spawning may be estimated. Most importantly, the study also has academic merit as little work has been undertaken in this field. Although the observational method used in this study was adequate for the purposes of the investigation, future work of this nature should incorporate other methods of documenting gonadal development such as gonadal staging and GSI in order to obtain more conclusive results.

Dans son Historia Animalium en 343 av. J.C., Aristote proposait déjà deux critères qui continuent d’être les bases fondamentales de notre compréhension de la diversité des modes de reproduction : l’origine des nutriments des embryons (lécitotrophie vs. matrotrophie) et le mode de parition (oviparité vs. viviparité). Depuis plusieurs décennies la compréhension de la transition évolutive vers la viviparité a attiré un intérêt scientifique considérable. En effet les analyses phylogénétiques récentes reconnaissent une évolution indépendante de la viviparité dans plus de 150 lignées de vertébrés dont au moins 115 concernent uniquement le taxon des reptiles squamates actuels (lézards, serpents et amphisbènes). Les lignées présentant une transition évolutive de l’oviparité à la viviparité chez les squamates se retrouvent généralement associées aux climats froids, mais pas uniquement. Les explications proposées pour ce patron reposent sur le contrôle comportemental de la température de développement chez les femelles gestantes, offrant ainsi des températures plus favorables que celles des sites de ponte situés sous la surface du sol. Durant cette thèse doctorale nous avons étudié une espèce à reproduction bimodale (Zootoca vivipara) chez qui coexistent des populations ovipares et vivipares disjointes. Ce contexte nous a permis de comparer les modes reproducteurs en minimisant les biais phylogénétiques. Nous avons pu mettre en évidence et quantifier différents coûts « potentiels » de la reproduction (énergétique, contrainte volumique, phénotype des nouveau-nés) et certains bénéfices (phénologie et performance des nouveau-nés) associés à la régulation maternelle du développement. Nos résultats nous amènent à discuter des différentes pressions de sélection s’exerçant sur la durée de rétention des embryons, dont les directions seraient opposées et/ou dont l’intensité serait variable au cours du développement embryonnaire. Dans ce schéma, la viviparité ne devrait être favorisée que dans des contextes plus contraignants et où les bénéfices thermiques compensent les coûts de prolongation de la rétention. Ce contexte sélectif aurait abouti chez les squamates à l’existence de deux modalités reproductives avec entre elles une instabilité évolutive des états intermédiaires. / In his Historia Animalium in 343 B.C., Aristotle proposed two fundamental distinguishing criteria for reproductive diversity: the source of nutrients for embryonic development (lecitotrophy vs. matrotrophy) and partuition mode (oviparity vs. viviparity). Understanding the evolutionary transition to viviparity attracted considerable scientific interest over the past few decades. Phylogenetic analyses indicate that viviparity has originated independently in more than 150 vertebrate lineages, including in a minimum of 115 clades of extant squamate reptiles (lizards, snakes and amphisbaenians). Transitions from oviparity to viviparity in squamate reptiles seem closely related to cold climates, but not exclusively. Explanations for this pattern are based on the fact that pregnant females can behaviouraly thermoregulate and thus offer more suitable developmental temperatures than those available in nests under the soil surface. During this PhD thesis we studied a reproductively bi-modal species (Zootoca vivipara) in which non-overlapping oviparous and viviparous populations exist. This context allowed us to compare oviparous and viviparous reproductive modes while minimizing phylogenetic biases. We identified and quantified potential reproductive costs (energy, volume constraints, offspring phenotype) and also benefits (phenology and offspring performances) associated with maternal thermoregulation. Our results provide support for multiple selective pressures on embryo retention, with variable intensities and opposite directions depending on embryonic developmental stage. In this scheme, viviparity should be selected in constraining environments where thermal advantages exceed the costs of increased retention. This context may explain the dichotomy observed in squamate reproductive modes and the evolutionary instability of intermediate stages.

To date, models of sexual size dimorphism do not explain selection for small females, and they are also limited in their ability to explain intraspecific variation in sexual size dimorphism. I propose that small females, in species which produce multiple clutches in a breeding season, could have a selective advantage if the interval between clutches is shorter for small clutches of eggs. When the breeding season is long, small females may produce more eggs in total than large females by producing more clutches, and thus small size could be selected for. Two populations of threespine stickleback (Gasterosteus aculeatus) showing divergence in the sexual bias of size dimorphism were used to determine if large or small females had a seasonal fecundity advantage in these multiple spawning fish, and whether the two populations had diverged in life-history characteristics (age at first reproduction, number of clutches, length of breeding season). In addition, the mechanisms by which the differences in size were achieved was investigated. Size-frequency diagrams obtained from field samples indicated that the Lewis Slough population was an annual one, while fish at the Angus Campbell site apparently survived for more than one breeding season. The larger size of females at the Angus Campbell site resulted primarily from continued growth with age, while males stopped growing in about one years time. In an environment chamber female fish from Lewis Slough grew more slowly, as they approached maturity, than males and were therefore were smaller than males. Data from field collections, fry raised to maturity in an environment chamber, and females individually monitored in captivity over the course of a breeding season indicated that the populations have diverged in life-history characters. Females from the Angus Campbell ditch site produced fewer clutches and eggs over the breeding season (a measure of reproductive effort), delayed maturity and matured at a greater size, and had a longer life-span than Lewis Slough females. These observations are more in accordance with the predictions from bet-hedging theory than r & K selection theory. Data from individually monitored females held in a common environment indicated that clutch size and interclutch interval increased with increasing body size but small females still did not attain the seasonal fecundity advantage predicted by the model. However, these results suggest that small females are capable of achieving a greater seasonal fecundity relative to large females than would be predicted by the difference in average clutch size alone. Actual counts of the total numbers of eggs produced by individuals in a breeding season showed seasonal fecundity to be independent of body size. Female body size and fecundity are more weakly linked than previously realized and this confers an increased flexibilty for responding to diverse selective pressures. / Science, Faculty of / Zoology, Department of / Graduate

Orientador: Wilma De Grava Kempinas / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Campinas / Made available in DSpace on 2018-08-31T09:26:34Z (GMT). No. of bitstreams: 1 Fernandes_GlauraScantamburloAlves_M.pdf: 2208578 bytes, checksum: d3b7d19f0c07858ed0bc399fa4af2b7d (MD5) Previous issue date: 2005 / Resumo: O diuron (3-(3,4-diclorofenil)-1,1-dimetilurea) é um herbicida uréico cuja DL50 oral aguda em raios é igual a 3400 mg/Kg. É muito utilizado na agricultura e seus efeitos no organismo animal ainda são pouco conhecidos, principalmente no sistema reprodutor. O objetivo deste trabalho foi avaliar o possível efeito tóxico do diuron no sistema reprodutor masculino. Para tanto, ratos machos adultos (9 ou 10 animais por grupo) receberam durante trinta dias consecutivos, por gavage (via oral). 125 ou 250 mg/Kg/dia de diuron (grau técnico) dissolvido em óleo de milho. O grupo controle recebeu apenas o veículo, segundo o mesmo protocolo experimental. Ao final do tratamento, os órgãos reprodutores, fígado e rins foram coletados e pesados. Alguns dos testículos e epídídimos foram utilizados para a contagem de espermatozóides e amostras de fígado e rins para quantificar resíduos de diuron por cromatografia gasosa. Um outro grupo de animais foi avaliado quanto ao comportamento sexual e fertilidade, sendo acasalados com fêmeas em estro natural. Ao final do tratamento, resíduos de diuron foram encontrados no fígado de todos os ratos tratados e houve aumento do peso desse órgão nas duas doses. A exposição ao diuron não provocou diferenças estatisticamente significativas nas concentrações de testosterona. produção espermática diária, reservas espermáticas no epidídimo e morfologia dos espermatozóides. O comportamento sexual não se alterou devido ao tratamento, porém houve diminuição estatisticamente significativa do número de fetos produzidos por ratas que acasalaram com machos tratados com a menor dose. Concluiu-se que a dose de 125 mg/Kg de diuron administrada nessas condições experimentais, foi tóxica do ponto de vista reprodutivo. / Abstract: Diuron (3,4-dichlorophenyl)-1,1-dimethylurea) is a ureic herbicide whose acute oral LD50 in rats is 3400 mg/Kg. It is widely utilized in agriculture and its effects in the animal organism are still poorlv known, especially in the reproductive system. The aim of this work was to evaluate a possible toxic effect of diuron on the male reproductive system. For this, adult male rats (9 or 10 animals per group) received, for 30 consecutive days, by oral gavage. 125 or 250 mg/Kg/day of diuron (technical grade) dissolved in corn oil. The control group received only the vehicle, following the same experimental protocol. At the end of the treatment, male reproductive organs, liver and kidneys were collected and weighed. Some of the testis and epididymis were utilized for sperm counts, and samples of liver and kidneys to quantify diuron residues, by gas chromatography, Another group of animals was evaluated with respect to sexual behavior and fertility, being mated with females in natural estrous. At the end of the treatment, residues of diuron were found in the liver of all treated rats and there was an increase of the weight of this organ in both doses. The exposure to diuron did not provoke statistically significant differences in testosterone concentration, daily sperm production, sperm reserves in the epididymis or sperm morphology. Sexual behavior was not altered due to the treatment, however there was statistically significant diminution in the number of fetuses produced by rats that mated with males treated with the lower dose. It was concluded that the dose of 125 mg/Kg of diuron. administered in these experimental conditions, was toxic from the reproductive point of view. / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

Chez les animaux, l’hermaphrodisme et le gonochorisme sont tous deux apparus plusieurs fois de manière indépendante. Cependant, les voies évolutives impliquées dans la transition entre les systèmes sexuels sont en grande partie inconnues. L’objectif de cette thèse était donc d’étudier la transition évolutive de l’hermaphroditisme vers des sexes séparés chez les vers du genre Ophryotrocha, en s'intéressant en particulier à la manière dont la coopération et la compétition entre individus peuvent déterminer l’allocation de ressources reproductives chez les hermaphrodites, soit en favorisant l'évolution de sexes séparés ou en stabilisant l'hermaphrodisme. Nos résultats ont révélé que les vers hermaphrodites échangent réciproquement des œufs, une forme de coopération qui favorise une allocation des ressources sexuelles biaisée en faveur de la fonction femelle et qui stabilise ainsi l'hermaphrodisme. Toutefois, lorsque les hermaphrodites sont exposés à une forte compétition pour l'accouplement, ils transfèrent les ressources de la fonction femelle vers la fonction mâle, ce qui diminue la production d’œufs et les soins parentaux, mais augmente la motilité et l'agressivité. À des niveaux élevés de compétition pour l'accouplement, motilité et agression peuvent améliorer la recherche et la monopolisation du partenaire, favorisant ainsi la propagation des hermaphrodites biaisés en faveur de la fonction mâle, promouvant ainsi l'évolution de mâles purs et, ensuite, de femelles pures. Enfin, nous avons montré que les hermaphrodites prêts à s'accoupler en tant que mâles uniquement (sans œufs matures) préfèrent des partenaires hermaphrodites prêts à s'accoupler en tant que femelles, qui, en revanche, n'expriment aucune préférence. Globalement, ce travail montre que la coopération et la compétition sont tous deux des facteurs importants dans la répartition des sexes chez les hermaphrodites et suggère que des changements dans l’environnement social ont pu jouer un rôle central dans l’évolution des systèmes sexuels chez les vers du genre Ophryotrocha. / In animals, both simultaneous hermaphroditism and gonochorism originated independently several times. Yet the evolutionary pathways involved in the transition between sexual systems are largely unknown. The aim of this thesis is therefore to investigate the evolutionary transition from hermaphroditism to separate sexes in Ophryotrocha worms, focusing on how cooperation and competition between individuals shape hermaphrodite sex allocation, either promoting the evolution of separate sexes or stabilizing hermaphroditism. Our results revealed that hermaphroditic worms reciprocally exchange egg-clutches, a form of cooperation that favor a female-biased sex allocation and stabilizes hermaphroditism. However, when hermaphrodites are exposed to high level of mate competition, they reallocate resources from the female to the male function, decreasing egg production and parental care and increasing motility and aggression. Under high mate competition level, motility and aggression may improve mate searching and partner monopolization and may favor the spread of male-biased hermaphrodites, promoting the evolution of pure males and, later, pure females. Finally, we showed that hermaphrodites ready to mate as males only (without ripe eggs) prefer hermaphrodites ready to mate as females as partners, which, in contrast, do not express any preference. Overall, this work shows that both cooperation and competition are important factors in hermaphrodite sex allocation, and suggests that changes in the social environment may have played a central role in the evolution of sexual systems in Ophryotrocha worms.

L’objectif de cette thèse est d’étudier le rôle de neuropeptides cérébraux, telle que la Neurokinin B codée par le gène tac3, dans le contrôle de la reproduction d’une espèce en danger, l’anguille Européenne, Anguilla anguilla. La maturation sexuelle de l’anguille est bloquée à un stade prépubertaire avant la migration océanique. Etant donnée sa position phylogénétique basale parmi les téléostéens, l’anguille est un modèle pertinent pour étudier l’évolution moléculaire et fonctionnelle de neuropeptides d’intérêt. Deux gènes paralogues tachykinine 3 (tac3) ont été identifiés dans le génome de l’anguille, chacun codant pour deux peptides. Ces gènes paralogues résultent de la duplication complète du génome spécifique aux téléostéens, comme le montrent les analyses phylogénétiques et synténiques. Les analyses de qPCR montrent que les deux gènes sont exprimés dans le cerveau. Les quatre peptides d’anguille ont été synthétisés et testés sur des cultures primaires de cellules hypophysaires d’anguille. Les quatre peptides inhibent l’expression de l’hormone lutéinisante et d’un récepteur à la gonadolibérine, révélant un double rôle inhibiteur dans le contrôle de la reproduction. / The aim of this PhD is to investigate the role of brain neuropeptides, such as neurokinin B, encoded by tac3 gene, in the control of reproduction of an endangered species, the European eel, Anguilla anguilla. The sexual maturation of the eel is blocked at a prepubertal stage before the oceanic migration. Due to its basal phylogenetic position among teleosts, the eel is also a relevant model for studying molecular and functional evolution of key neuropeptides. Two tachykinin 3 (tac3) paralogous genes were identified in the eel genome, each encoding two peptides. These paralogs result from the teleost-specific whole genome duplication, as shown by phylogeny and synteny analyses. Both genes are expressed in the brain as shown by qPCR. The four eel peptides were synthesized and tested on primary cultures of eel pituitary cells. The four peptides inhibited the expression of luteinizing hormone and gonadotropin-releasing hormone receptor, revealing a dual inhibitory role in the control of reproduction.

Philosophiae Doctor - PhD / This thesis investigates socio-spatial trajectories of class formation and processes of accumulation from below and above on redistributed farmland, the ‘New Qwaqwa Farms’ in the Eastern Free State province of South Africa, from the mid-1980s to 2016. Class formation trajectories of the studied land beneficiaries are traced across localised historical geographies and political contexts, from apartheid to the current democratic dispensation, that is, from the land beneficiaries’ recent ancestral history as labour tenants on white-owned farmland, and subsequent systematic expulsions from farmland, to their Bantustan labour reserve resuscitations as mainly nonagricultural petty commodity producers, and later targeting for land reform, as one measure of redistribution.

A highly specific steroid regulated transcription system system in Saccharomyces cerevisae was used to screen for phytoestrogens indioecious plants. Yeast cells were co-transformed with a human estrogen receptor expression plasmid and a reporter plasmid containing the E. coli β-galactosidase gene.

No description available.

No description available.