Sperm Competition
Mostrando 1-12 de 41 artigos, teses e dissertações.
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1. Influência da recópula de fêmeas selvagens de Ceratitis capitata (Wied., 1824) (Diptera: Tephritidae) na eficiência da técnica do inseto estéril / Influence of wild Ceratitis capitata (Wied., 1824) (Diptera: Tephritidae) females remating on the efficiency of the sterile insect technique
The sterile insect technique (SIT) aim at the induction of sterility in wild females by mating with sterile males released in great amounts in the field. These released males must compete with wild ones being able to attract and mate wild females, fertilize their eggs and avoid remating with a wild male that would lead to fertile eggs and consequently reduce
Publicado em: 2009
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2. Caracteres morfológicos do sistema reprodutor masculino e dos espermatozóides de Hymenoptera e Hemiptera (Insecta) e suas possíveis contribuições para a sistemática / Morphological characters of the male reproductive system and spermatozoa of the Hymenoptera and Hemiptera (Insecta) and their possible contributions to the systematics
Os insetos constituem os organismos mais diversos na Terra, sendo seu sucesso adaptativo atribuído a longevidade de suas linhagens, ao número de espécies, à diversidade de suas adaptações, sua biomassa e seu impacto ecológico. Devido à grande variedade de histórias de vida e padrões ecológicos, os insetos apresentam grande diversidade no comportam
Publicado em: 2009
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3. Reproductive biology of the harvestman Acutisoma proximum (Arachnida: Opiliones) : alternatives mating strategies among males and maternal care / Biologia reprodutiva do opilião Acutisoma proximum (Arachnida: Opiliones) : estrategias alternativas de acasalamento em machos e cuidado parental em femeas
Not informed
Publicado em: 2008
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4. Socialidade em sagüis do cerrado (Callithrix Penicillata): estratégias comportamentais nas relações intra e intergrupo
The present work investigated the social relationships in the Cerrados marmoset (Callithrix penicillata). Behavioural data from a wild group helped to understand both within and between group social patterns. The analyses of the within-group agonistic interactions showed a hierarchic structure with the reproductive female as the dominant. There were no clear
Publicado em: 2006
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5. Individual adjustment of sperm expenditure accords with sperm competition theory
Sperm competition theory predicts that males should strategically allocate their sperm reserves according to the level of sperm competition, defined as the probability that the sperm of two males compete for fertilizing a given set of ova. Substantial evidence from numerous animal taxa suggests that, at the individual level, sperm expenditure increases when
The National Academy of Sciences.
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6. Sperm competition experiments between lines of crickets producing different sperm lengths.
Sperm numbers can be important determinants of fertilization success in sperm competition. However, the importance of variation in sperm size is less well understood. Sperm size varies significantly both between and within species and comparative studies have suggested that some of this variance can be explained by sperm competition. In this study we examine
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7. Patterns of sperm precedence and predictors of paternity in the Trinidadian guppy.
Despite its widespread occurrence in animals, sperm competition has been studied in a limited range of taxa. Among the most neglected groups in this respect are internally fertilizing fish in which virtually nothing is known about the dynamics of sperm competition. In this study, we examined the outcome of sperm competition when virgin female guppies mated w
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8. Tactic-specific success in sperm competition.
Sperm competition is a major force in sexual selection, but its implications for mating-system and life-history evolution are only beginning to be understood. The well-known sneak-guard model predicts that sneaks will win in sperm competition. We now provide empirical confirmation of this prediction. Bluegill sunfish (Lepomis macrochirus) have both sneak (cu
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9. Topping off: A mechanism of first-male sperm precedence in a vertebrate
Competition among the sperm of rival males is an important evolutionary phenomenon in many organisms. Yet, despite extensive research on sperm competition in some vertebrate taxa, very little progress has been made on this topic in amphibians. Urodele amphibians (newts and salamanders) are of particular interest to theories of sperm competition because most
The National Academy of Sciences.
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10. Experimental analysis of sperm competition mechanisms in a wild bird population
Recent work on wild birds has revealed the importance of sperm competition as a source of sexual selection, but behavioral and paternity studies have previously provided only indirect evidence for mechanisms of sperm competition in wild birds. In a field study of collared flycatchers Ficedula albicollis we used a previously uncharacterized method to determin
National Academy of Sciences.
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11. Sperm Competition and Sperm Loss in DROSOPHILA MELANOGASTER Females Fertilized by YSX·YL/0 Males
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12. Sperm quality in the alternative reproductive tactics of Atlantic salmon: the importance of the loaded raffle mechanism.
The outcome of sperm competition in species with alternative male reproductive strategies may be determined by fair or loaded raffle mechanisms. The sperm production and quality of male Atlantic salmon using alternative reproductive tactics were investigated in order to determine the relative importance of sperm quality for male reproductive success. Sexuall