166 resultados para paternity success

em Deakin Research Online - Australia


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Background
A large number of studies in postcopulatory sexual selection use paternity success as a proxy for fertilization success. However, selective mortality during embryonic development can lead to skews in paternity in situations of polyandry and sperm competition. Thus, when assessment of paternity fails to incorporate mortality skews during early ontogeny, this may interfere with correct interpretation of results and subsequent evolutionary inference. In a previous series of in vitro sperm competition experiments with amphibians (Litoria peronii), we showed skewed paternity patterns towards males more genetically similar to the female.

Methodology/Principal Findings
Here we use in vitro fertilizations and sperm competition trials to test if this pattern of paternity of fully developed tadpoles reflects patterns of paternity at fertilization and if paternity skews changes during embryonic development. We show that there is no selective mortality through ontogeny and that patterns of paternity of hatched tadpoles reflects success of competing males in sperm competition at fertilization.

Conclusions/Significance
While this study shows that previous inferences of fertilization success from paternity data are valid for this species, rigorous testing of these assumptions is required to ensure that differential embryonic mortality does not confound estimations of true fertilization success.

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For dioecious animals, reproductive success typically involves an exchange between the sexes of signals that provide information about mate location and quality. Typically, the elaborate, secondary sexual ornaments of males signal their quality, while females may signal their location and receptivity. In theory, the receptor structures that receive the latter signals may also become elaborate or enlarged in a way that ultimately functions to enhance mating success through improved mate location. The large, elaborate antennae of many male moths are one such sensory structure, and eye size may also be important in diurnal moths. Investment in these traits may be costly, resulting in trade-offs among different traits associated with mate location. For polyandrous species, such trade-offs may also include traits associated with paternity success, such as larger testes. Conversely, we would not expect this to be the case for monandrous species, where sperm competition is unlikely. We investigated these ideas by evaluating the relationship between investment in sensory structures (antennae, eye), testis, and a putative warning signal (orange hindwing patch) in field-caught males of the monandrous diurnal painted apple moth Teia anartoides (Lepidoptera: Lymantriidae) in southeastern Australia. As predicted for a monandrous species, we found no evidence that male moths with larger sensory structures had reduced investment in testis size. However, contrary to expectation, investment in sensory structures was correlated: males with relatively larger antennae also had relatively larger eyes. Intriguingly, also, the size of male orange hindwing patches was positively correlated with testis size.

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In a recent paper, we demonstrated that male-female genetic relatedness determines male probability of paternity in experimental sperm competition in the Peron's tree frog (Litoria peronii), with a more closely related male out-competing his rival. Here, we test the hypothesis that a male-male difference in siring success with one female significantly predicts the corresponding difference in siring success with another female. With male sperm concentration held constant, and the proportion of viable sperm controlled statistically, the male-male difference in siring success with one female strongly predicted the corresponding difference in siring success with another female, and alone explained more than 62 per cent of the variance in male-male siring differences. This study demonstrates that male siring success is primarily dictated by among-male differences in innate siring success with less influence of male-female relatedness.

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Although the majority of passerine birds are socially monogamous, true genetic monogamy is rare, with extra-pair paternity (EPP) occurring in almost 90% of surveyed socially monogamous species. We present the first molecular data on the genetic breeding system of the long-tailed finch, Poephila acuticauda, a grass finch endemic to the tropical northern savannah of Australia. Although the species forms socially monogamous pair bonds during the breeding season, we found that extra-pair males sired 12.8% of 391 offspring, in 25.7% of 101 broods. Our findings provide only the second estimate of extra-pair paternity in the estrildid finch family.

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Small to medium-sized enterprises (SMEs) contribute significantly to national economies and employment levels and represent a viable source for inventions and innovations. The emergence of electronic commerce in the early 90's could provide different opportunities to the small business sector to overcome its inadequacies. However, in view of the electronic commerce/business (EC) literature in organizations in general and in SMEs specifically, EC research is scarce. Available research portrays a gloomy picture about EC uptake and use by SMEs. Therefore, this chapter attempts, by reviewing recent EC research, to depict an agenda for EC success in SMEs made up of ten influencing factors. Thus, an attempt is made to develop deeper understanding about the factors influencing EC success in SMEs. By following the suggested guidelines in this chapter, SMEs would be in a better position to assess the Viability o/the new EC perspective 10 their organizations. The same factors are highly important to researchers, SMEs, professionals (including educational institutions) and policymakers in driving SMEs and EC forward.

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Hallmark sporting events often are commercially driven entertainment entities which represent an economically important part of the overall sport industry. Because of the high popularity of international sporting contests, hallmark sporting events attract significant commercial, media, and consumer attention. Cities around the world are beginning to understand the potential of using these events to draw attention to the host city, which is why the market for hallmark sporting events is becoming increasingly competitive. In order to award the hosting of the event to the most suitable organizer, event owners often require potential hosts to bid. The most important elements in this process have been largely based on logical assumptions rather than empirical data. This study focused on the bid process in order to ascertain the important elements essential in achieving a successful bid.

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Experience has shown that development NGOs typically do not succeed in transforming themselves into financially sustainable providers of financial intermediation services. The reasons for this failure are complex (see Dichter 1999). Nonetheless, the role that NGOs play as microfinance providers is important and the contribution they could make to poverty reduction would be greatly enhanced if they adhered to some simple but essential parameters of success.

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The paper examines the contributing factors to new product success within the Australian grocery market. A review of the literature on new product success factors and reasons for failure is presented. The research identifies reasons for failure of new products as well as reasons for success. The main reasons for new product failure are incorrect pricing, poor marketing, wrong product launch timing, poor distribution and lack of marketing funds. For new product success it is critical to have strong leadership, competent staff and an on-going new product development process.

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Objective: To examine perceptions of success in weight control and future weight-control intentions in a community sample. Design: Cross-sectional postal survey. Subjects: There were 1500 adults randomly selected from the Electoral Roll of Victoria (47% response). Setting: Community. Main outcome measures: Retrospective weight change over previous 12 months; perceived weight-control success; future weight-control intentions. Statistical analyses: Pearson's χ² tests were used to compare perceived weight-control success by sex, and by age, education level, initial BMI, amount of weight change and weight-loss behaviour within sex. ANOVA was used to compare mean weight change associated with perceived weight control success within sex, and within age, education, body mass index and weight-loss behaviour by sex. The distribution (frequency) of weight-control intentions are reported within perceived weight-control success and amount of weight change. Results: One in two (53%) reported maintaining their weight within 1kg in the preceding 12 months, 26% of men and 21% of women reported weight gain and 20% of men and 26% of women reported weight loss. Almost one-third (30%) of those who maintained their weight considered themselves unsuccessful. A majority of those who lost weight considered themselves successful at controlling their weight. However, more than 45% of men who gained weight also considered themselves successful. Those who considered themselves unsuccessful experienced less weight loss (1.1 ± 3.9kg) than those who considered themselves quite successful (-1.4 ± 4.5 kg, P < 0.001) or very successful (-1.3 ± 7.8 kg, P < 0.001). Conclusion: Public views of what constitutes successful weight control may need to be reoriented to be consistent with public health goals.

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The world of telecommunications, especially mobile communications, continues to evolve with innovative technologies and high-speed data services. In many economies, mobile phones have overtaken fixed lines. In this dynamic context, we have envisaged to study mobile communication diffusion in Germany and India, from a historical comparative perspective. The basic standard for comparison has been Global Systems for Mobile Communications (GSM) and its data services, which was adopted by both economies. Subsequently, critical success factors in each economy is drawn and compared with the other, to elicit future directions.

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The implementation of various management systems and standards has become an important activity for organisations irrespective of their size, sector or nature of the business. Even with a history of implementing change across the organisation, managers continue to experience resistance and challenges when implementing and maintaining the systems/standards, whether they be in quality, occupational health and safety, environmental or any other area. Based on a major research project recently completed, this paper presents the critical success factors for successful implementation of an environmental management system. The project involved three phases of fieldwork: preliminary interviews, a questionnaire survey and in-depth interviews. A brief summary of the findings from each of these phases of research is presented. Based on the findings, the paper discusses the critical success factors for the successful implementation and maintenance of EMS.

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Small to medium-sized enterprises (SMEs) contribute significantly to the national economies and to the employment levels of different countries and represent a viable source for inventions and innovations. The recent emergence of electronic commerce in the early nineties could provide different opportunities to the small business sector to overcome its inadequacies. However, in view of the electronic commerce/business (EC) literature in organisations in general and in SMEs specifically, it was observed that EC research is scarce. Therefore, this research attempts, by reviewing relevant EC literature, to develop deeper understanding about the factors influencing EC success in SMEs. The researcher found the following issues significantly influence EC success in SMEs: e-Value, e-Cost, e-Transformation, e-Product, e-Nvolvement, e-Nnovativeness, e-Competition, external e-Support, and e-Pressure. These factors are of importance to researchers, SMEs, professionals including educational institutions and policymakers in driving SMEs and EC forward.

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