96.2 Saturday, Jan. 7 Prolactin as a mediator of the stress response in parent birds: an underappreciated mechanism ANGELIER, F*; CHASTEL, O; CEBC, CNRS, France; CEBC, CNRS, France email@example.com
In birds, an emergency life-history stage (ELS) is expressed when the immediate survival is threatened by stressful events. This ELS redirects the individual away from the breeding stage so that it can cope with the perturbation and survive in the best condition possible. At the proximate level, this ELS is promoted by an increased secretion of corticosterone and, during the last two decades, most studies have been focusing on this stress hormone. However, other underappreciated endocrine mechanisms may be involved in the activation of ELS. Thus, prolactin probably deserves attention when focusing on the parental phase because this hormone is involved in the regulation of parental cares in vertebrates. Despite this potential, almost no study had examined how stressful events can affect prolactin levels in birds. Over the past 6 years, we investigated the inter-relationships between stress, prolactin, parental cares and fitness in bird species. We reported that stress-related decreases of prolactin levels are a general pattern during the parental phase. In addition, we showed that stress-related decreases of prolactin levels are rapid (within 30 min), and associated with a reduction of parental cares and with a low reproductive success. This demonstrates therefore that prolactin can be involved in the activation of an ELS during the parental phase. Interestingly, we also reported a large inter-individual variability in the prolactin stress-response, suggesting that all parents are not similarly sensitive to stress. Indeed, we found that several factors can affect prolactin levels and explain this inter-individual variability (age, experience, condition, etc.). Finally, we illustrated that the modulation of the prolactin stress response is appropriate to study life-history trade-offs and parental strategies in an evolutionary context.