Resolving the life-history trade-off paradox: Measuring resource acquisition to reveal life-history trade-offs over different temporal scales

解决生活史权衡悖论：衡量资源获取以揭示不同时间尺度的生活史权衡

• 批准号: NE/X000680/1
• 负责人: Samantha Patrick
• 金额: $ 76.13万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX000680%2F1
• 关键词: Resolving; life; history; trade; off

For species and populations to persist, individuals must reproduce. However, there are constraints on reproductive output, because without these, individuals would have limitless young. As such, pivotal models in evolutionary ecology demonstrate a cost to reproduction which manifests as a reduction in survival probability, and hence future reproductive output. However, although studies have modelled individual life-history pathways, they have rarely detected these trade-offs in the wild. Although the trade-off between current and future reproduction is widely accepted to exist, it continues to evade detection. We suggest there are two main reasons why this is the case:First, the trade-off between current versus future reproduction is driven by resources. These are generally limited so they must be divided between current and future reproductive effort. Attempts to estimate how these resources are allocated are hampered by the inability of most studies to measure actual resource values for each individual. If we don't know how many resources an individual has we can not understand how these are divided between life-history traits.Second, it is known that individuals can show differences in whether they use their resources for current or future reproduction. But when is the future? To individual A the future may be the next breeding attempt but to individual B the future may be much later in life. However, surprisingly studies fail to model such differences between individuals. Simulations have shown that fixing the temporal scale of trade-offs will fail to detect trade-offs that occur at another temporal scale and hence could be a major driver in masking trade-offs.Our model system provides data on the reproductive and foraging behaviour of albatrosses at four sites throughout the Southern Ocean. We have evidence from our study system of substantial variation in individual foraging behaviour, and hence the resources available for reproduction. We know that some individuals show variation in reproductive success over short time frames, and others over very long periods of their life. Hence, individual level analyses are required to measure the effects of changes in resources and consequences for reproduction. We will use existing long-term data on breeding behaviour (>100,000 breeding attempts; 63-year time series) and foraging (1305 individuals; 25-year time series), coupled with newly collected data (150 individuals), to examine how individuals vary in the resources they have available, and how they use them. We expect resource acquisition to be crucial to how many resources are allocated to reproduction, so that by capturing these measures, we will be able to detect previously hidden trade-offs between current and future reproduction. We expect that individuals will pay the cost of reproduction at different time points in the future, and that by allowing these differences to be modelled, we will be able to accurately detect reproductive trade-offs. The environment will change the resources available over time and we predict that some life-history strategies will be under selection as they enable individuals to maximise fitness in a changing climate. By modelling how fitness varies under future climate conditions we can predict how natural selection will act on individual life-history strategies.

为了使物种和种群持续存在，个人必须繁殖。但是，对生殖产量有限制，因为没有这些，个人将拥有无限的年轻人。因此，进化生态学中的关键模型表明了生殖成本，这表现为降低生存概率，因此将来的生殖产量。但是，尽管研究已经建模了个体生活途径，但他们很少在野外检测到这些权衡。尽管当前和将来的繁殖之间的权衡已被广泛接受，但它继续逃避检测。我们建议这样的情况有两个主要原因：首先，当前的繁殖与未来繁殖之间的权衡是由资源驱动的。这些通常受到限制，因此必须将它们划分为当前和将来的生殖工作。大多数研究无法衡量每个人的实际资源价值，试图估计如何分配这些资源。如果我们不知道个人有多少资源，我们将无法理解它们如何在生活历史的特征之间分配。但是未来是什么时候？对于个人而言，未来可能是下一个繁殖尝试，但是对于个人而言，未来可能会在生活中更晚。但是，令人惊讶的是，研究无法模拟个人之间的这种差异。模拟表明，修复权衡的时间尺度将无法检测到在另一个时间尺度上发生的权衡，因此可能是掩盖折衷方案的主要驱动力。我们从研究系统中有证据表明，个人觅食行为的实质性差异，因此有可用于生殖的资源。我们知道，有些人在短时间内表现出生殖成功的差异，而另一些人则在他们的一生中表现出差异。因此，需要进行个体级别的分析来衡量资源变化和繁殖后果的影响。我们将使用现有的有关育种行为的长期数据（> 100,000种繁殖尝试； 63年的时间序列）和觅食（1305个个人； 25年的时间序列），再加上新收集的数据（150个人），以检查个人在可用资源中的变化以及如何使用它们。我们预计资源获取对于分配多少资源要复制至关重要，因此，通过捕获这些措施，我们将能够检测到当前和未来复制之间先前隐藏的权衡。我们预计个人将来将在不同时间点支付繁殖成本，并且通过允许对这些差异进行建模，我们将能够准确地检测生殖权衡。环境将随着时间的流逝而改变可用的资源，我们预计某些生活史策略将在选择中，使个人在不断变化的气候下最大化健身。通过对未来气候条件下的健身变化进行建模，我们可以预测自然选择将如何对单个生活寿命策略作用。