Abstract
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.
United Kingdom