Data from: Asynchronous hatching in a non-avian species: a test of the hurry-up hypothesis

The hurry-up hypothesis suggests that completing reproduction as soon as possible is favoured when the quantity or quality of resources used for breeding declines over time. However, completing reproduction sooner may incur a cost if it leads to an asynchronous hatching pattern that reduces overall growth and survival of offspring. Here, we present the first test of the hurry-up hypothesis in a non-avian system, the burying beetle Nicrophorus vespilloides, which breeds on small vertebrate carcasses. To this end, we conducted two experiments in which we provided females with an incentive to complete reproduction sooner by giving them carcasses that varied either with respect to decomposition (decomposed or fresh) or size. We recorded the delay until laying, and measures of the laying pattern and fitness consequences for the offspring. As predicted, we found that larvae dispersed from the carcass earlier when females commenced oviposition sooner and that laying spread was greater when females commenced egg laying earlier. However, we found no evidence that females commenced egg laying earlier on either decomposed or larger carcasses. Our results suggest that, although asynchronous hatching might emerge as a by-product of parents attempting to complete reproduction sooner, there is no evidence that females attempt to complete reproduction sooner under conditions where this would be favourable. Our results are therefore inconsistent with the hurry-up hypothesis.

加急繁殖假说（hurry-up hypothesis）指出，当繁殖可用资源的数量或质量随时间递减时，自然选择将青睐于尽快完成繁殖的个体。但若提前完成繁殖导致后代出现异步孵化模式，进而降低子代整体的生长速率与存活率，则需承担相应的适应性代价。本研究首次在非鸟类系统中对加急繁殖假说开展实验检验，实验对象为以小型脊椎动物尸体为繁殖基质的埋葬甲虫Nicrophorus vespilloides。为此，我们设计了两项实验：通过提供分解状态（腐解组与新鲜组）或体型大小存在差异的脊椎动物尸体，为雌性甲虫提供提前完成繁殖的选择诱因。我们记录了其产卵前的延迟时长、产卵模式相关指标，以及子代的适合度相关结果。正如实验预期，我们观察到雌性甲虫越早开始产卵，幼虫从繁殖尸体上分散的时间就越早；且雌性产卵起始越早，产卵跨度越大。但我们未发现雌性甲虫在腐解尸体或更大体型的尸体上会提前产卵的证据。我们的研究结果表明，尽管异步孵化可能是亲代试图提前完成繁殖过程的副产物，但并未发现雌性甲虫在适宜提前繁殖的条件下会主动提前完成繁殖。因此，本研究结果与加急繁殖假说并不相符。