23 research outputs found

    Superior sperm competitors sire higher-quality young

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    The evolution of polyandry remains controversial. This is because, unlike males, in many cases multiple mating by females does not increase fecundity and inevitably involves some costs. As a result, a large number of indirect benefit models have been proposed to explain polyandry. One of these, the good sperm hypothesis, posits that high-quality males are better sperm competitors and sire higher-quality offspring. Hence, by mating multiply, females produce offspring of superior quality. Despite being potentially widely applicable across species, this idea has received little attention. In a laboratory experiment with yellow dung flies ( Scathophaga stercoraria ) we found that males that were more successful in sperm competition also had offspring that developed faster. There was no relationship between paternal success in sperm competition and the ability of offspring to survive post-emergence starvation. Since faster development times are likely to be advantageous in this species, our data provide some support for polyandry evolving as a means of producing higher-quality offspring via sperm competition

    Polygyny, census and effective population size in the threatened frog, Rana latastei

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    Effective population size (Ne) is a key determinant of genetic diversity of populations. In amphibians, the ratio effective population size/census size (Ne/N) is often very low, raising concerns for the long-term persistence of genetic diversity in isolated populations. It has been proposed that the phenomenon of 'genetic compensation' increases the ratio Ne/N in small populations, but the underlying mechanisms are poorly understood. Polygyny can decrease Ne/N because of the negative relationship between polygyny and Ne. We used genetic information (microsatellites) to evaluate the relationship between census size, polygyny and Ne in populations of the threatened Italian agile frog Rana latastei. We reconstructed parentage in tadpoles from nine populations with eight to 32 breeding females, using a likelihood-based method; we analysed simulated datasets with known properties to confirm the reliability of this approach in reconstructing polygyny. Furthermore, we estimated Ne using approximate Bayesian computation. The level of polygyny differed strongly among populations (average number of mates per breeding male: 2-6.4). Polygyny was greater in populations with larger census sizes. Moreover, variance in male mating success was larger in large populations. Effective population size increased with population size, but was negatively related to polygyny; as polygyny increased in large populations, this was associated with reduced Ne/N. In polygynous species, increasing levels of polygyny in large populations may explain the low Ne/N values, with important implications for the conservation of genetic diversity and for long-term population persistence

    The Pandemic pathogen of amphibians, <i>Batrachochytrium dendrobatidis</i> (Phylum Chytridiomycota), in Italy

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    Worldwide amphibian declines and species losses are global problems and emerging infectious diseases have been identified as one of the major threats. The worst of these is chytridiomycosis, an amphibian disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Here we review what is known of the distribution of Bd and chytridiomycosis in Italy. We critically summarize the evidence in support of the hypothesis that Bd is an invasive pathogen in Italy. Last we provide recommendations for immediate research needs, both for basic science and applied conservation

    Biodiversity offsetting: what are the challenges, opportunities and research priorities for animal conservation?

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    [Extract] Governments, businesses, financial institutions and local communities are increasingly using biodiversity offsets, also known as compensatory mitigation, as a putative mechanism to achieve 'no net loss' (NNL) of biodiversity as a result of specific development projects (McKenney & Kiesecker, 2010; Quetier & Lavorel, 2011; Gardner et al., 2013). The Business and Biodiversity Offsets Programme (BBOP), an international collaboration for the development of offset methodologies, defines biodiversity offsets as 'the measurable conservation outcomes resulting from actions designed to compensate for significant residual adverse biodiversity impacts arising from project development after appropriate prevention and mitigation measures have been taken. The goal of biodiversity offsets is to achieve no net loss and preferably a net gain of biodiversity on the ground with respect to species composition, habitat structure, ecosystem function and people's use and cultural values associated with biodiversity' (BBOP, 2009). Proposals are already proceeding in the European Union (EU) for a NNL initiative as part of the 'EU Biodiversity Strategy to 2020' – with possible operational principles that include offsetting schemes (see http://ec.europa.eu/environment/nature/biodiversity/nnl/index_en.htm). Madsen et al. (2011) identified legislation mandating compensatory biodiversity conservation mechanisms (including offsets) in 45 countries, with a further 27 under development and this number is likely to have grown since

    Challenges and opportunities for animal conservation from renewable energy development

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    [Extract] Global climate change is among the greatest threats confronting both human and natural systems (IPCC, 2007). A substantial component of greenhouse gas (GHG) emissions is from energy production, generated via the burning of fossil fuels, especially coal, natural gas and refined petroleum. Given that reduction in global energy consumption is unlikely over the next century or so, renewable energy generation has been proposed as a low-carbon alternative to limit GHG emissions. Consequently, many national and regional governments have set targets for renewable energy manufacture and use (e.g. '20% Wind Energy by 2030' – DoE, 2008; EU, 2009). Nevertheless, despite the benefits associated with reducing carbon emissions, renewable energy development itself has important, sometimes severe, implications for the conservation of biodiversity that should not be ignored. A central challenge and opportunity for animal conservation is to understand and manage environmental problems associated with the rapid growth in renewable energy production, while simultaneously maintaining progress toward reducing dependence on fossil fuels

    What the 'food security' agenda means for animal conservation in terrestrial ecosystems

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    [Extract] The goal of the 'food security' agenda – to provide the world's population with a sustainable and secure supply of safe, nutritious, affordable and high-quality food (Research Councils United Kingdom, 2011) – comes with considerable challenges. To feed the expanding human population, numbered over 7 billion and growing (United Nations, Department of Economic and Social Affairs, Population Division, 2011), it is anticipated that by 2030, crop production must increase by 43% and meat production by 124% (Food and Agriculture Organisation, 2009). Growing demand is expected to result in escalating food prices as transport and storage costs increase, potentially reducing access to food among the world's poor. Given the past relationship between lack of access to affordable food and political instability (Brinkman & Hendrix, 2011), food security is given a high priority on global and national political agendas
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