Meeting Abstract
To maximize fitness, parents must tradeoff time and energy between parental care and self-maintenance. Factors such as hormones, clutch size, acute stressors and the external environment can influence parental care, which can then affect offspring development. In vertebrates, prolactin (PRL) and corticosterone (CORT) are two important hormones for parental investment because they stimulate parental care and mobilize energy, respectively, and can mediate the response to stressors. One of the most important parental care behaviors in birds is incubation, since small changes in egg temperature have large effects on offspring. To investigate how hormones may mediate incubation behavior, we collected baseline and stress-induced (30 min after capture) blood samples from female wood ducks (Aix sponsa) at the start and end of egg incubation. We also measured incubation behavior and temperature using artificial egg loggers. As expected, PRL decreased and CORT increased after 30 min of capture and restraint. Interestingly, PRL levels were higher at the end than the start of incubation and stress-induced PRL levels were positively related to the daily percentage of time spent incubating eggs. Further, the percentage of time spent incubating predicted the average and variability in egg temperature, after accounting for clutch size and ambient temperature. These results suggest that PRL increases as parental investment increases, that a dampened PRL stress response may be associated with the decision to stay on the nest despite stressors, and how parental behaviors may ultimately influence offspring fitness by modifying the early developmental environment.
