Parental responses to variation in egg odour during incubation

亲本通过决定孵化开始时间、孵化温度、巢小气候和转卵率，直接影响胚胎发育的速度和成功率。然而，与胎生动物不同的是，在胎生动物中，发育中的胚胎可能会将它们的发育需求传达给父母(例如通过激素)，导致它们的发育环境发生有益的变化，但对于卵子结合的胚胎来说，这并不容易。事实上，在胚胎发声系统发育到孵化期接近尾声之前，胚胎似乎几乎没有机会将它们的发育要求传达给孵化的父母，因此胚胎几乎没有机会通过操纵父母的行为来影响它们的微环境(例如，使它变暖或变冷)。基于试点数据显示，(A)蛋在整个孵化过程中释放足以提供关于它们的生存和热需求的信息的气味，以及(B)鸟类可以检测到这些气味，这一建议旨在检验新的假设，即孵化期间的胚胎需求可以通过鸡蛋产生的嗅觉线索来确定，并且父母不仅检测到这些线索，但也会相应地改变他们的行为。具体地说，使用可以释放出与真鸡蛋产生的气味相匹配的人造鸡蛋，我将测试(I)父母是否不太关注没有嗅觉发育迹象的鸡蛋(即，不育)(实验1)，以及(Ii)父母是否对嗅觉线索做出反应，这些线索与低温鸡蛋的行为一致，旨在提高鸡蛋温度(实验2)。这项工作不仅对鸟类嗅觉的研究做出了极其新颖的贡献，而且将是理解早期孵化期间胚胎与父母之间相互作用的第一步。鸟类嗅觉仍处于非常早期的阶段。拟议的实验结果将直接导致进一步的国家环境研究中心的资金申请，以探索这些相互作用对胚胎和它们的父母(S)的适合性后果，以及这些过程如何在自然巢中和跨物种运行。从长远来看，这也可能导致基于气味的系统的开发，以在商业上和圈养繁殖计划期间监测鸡蛋的发育。

Avian parents directly affect the rate and success of embryonic development by determining the onset of incubation, temperature during incubation, nest microclimate and the rate of egg turning. However, unlike in viviparous animals, where developing embryos can potentially communicate their developmental requirements to their parent (e.g. via hormones), resulting in beneficial changes to their developmental environment, this is not so easy for egg-bound embryos. Indeed, until the embryonic vocalisation system develops towards the end of the incubation period, there would appear little opportunity for embryos to convey their developmental requirements to incubating parents and therefore little opportunity for embryos to influence their microenvironment (e.g. to make it warmer or cooler) by manipulating parental behaviour.Based on pilot data showing that (a) eggs release odour throughout incubation that is sufficient to provide information on their viability and thermal requirements, and (b) that birds can detect these odours, this proposal aims to test the novel hypothesis that embryo requirements during incubation can be determined via olfactory cues produced by eggs, and that parents not only detect these cues, but alter their behaviour accordingly. Specifically, using artificial eggs that can release synthetic odours that match those produced by real eggs, I will test whether (i) parents pay less attention to eggs that show no olfactory signs of development (i.e., 'smell' infertile) compared to 'fertile' controls (Experiment 1), and (ii) parents respond to olfactory cues consistent with hypothermic eggs with behaviours intended to increase egg temperature (Experiment 2).This work will not only be an extremely novel contribution to the work on avian olfaction, which is still very much in its infancy, but will be the first step in understanding embryo-parent interactions during early incubation. The results of the proposed experiments will lead directly to further NERC funding applications to explore the fitness consequences of these interactions for embryos and their parent(s) and how these processes operate in natural nests and across species. In the longer term, it may also lead to the development of odour-based systems to monitor egg development both commercially and during captive breeding programmes.