Running title: Hurry-up hypothesis 10 2 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 15 burying beetle Nicrophorus

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... es, 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 20 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 25 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.