Does prolactin mediate parental and life-history decisions in response to environmental conditions in birds? A review

Abstract

This article is part of a Special Issue "Parental Care". In vertebrates, adjustments of physiology and behavior to environmental changes are often mediated by central physiological mechanisms, and more specifically by hormonal mechanisms. As a consequence, these mechanisms are thought to orchestrate life-history decisions in wild vertebrates. For instance, investigating the hormonal regulation of parental behavior is relevant to evaluate how parents modulate their effort according to specific environmental conditions. Surprisingly and despite being classically known as the 'parental hormone', prolactin has been overlooked in birds relative to this context. Our aim is to review evidence that changes in prolactin levels can mediate, at least to some extent, the response of breeding birds to environmental conditions. To do so, we first examine current evidence and limits for the role of prolactin in mediating parental behavior in birds. Second, we emphasize the influence of environmental conditions and stressors on circulating prolactin levels. In addition, we review to what extent prolactin levels are a reliable predictor of breeding success in wild birds. By linking environmental conditions, prolactin regulation, parental behavior, and breeding success, we highlight the potential role of this hormone in mediating parental decisions in birds. Finally, we also review the potential role of prolactin in mediating other life history decisions such as clutch size, re-nesting, and the timing of molt. By evaluating the influence of stressors on circulating prolactin levels during these other life-history decisions, we also raise new hypotheses regarding the potential of the prolactin stress response to regulate the orchestration of the annual cycle when environmental changes occur. To sum up, we show in this review that prolactin regulation has a strong potential to allow ecological physiologists to better understand how individuals adjust their life-history decisions (clutch size, parental behavior, re-nesting, and onset of molt) according to the environmental conditions they encounter and we encourage further research on that topic.

Canadian Arctic Contaminants and Their Effects on the Maternal Brain and Behaviour: A Scoping Review of the Animal Literature

“…Incubation behaviour is a critical component of offspring success in this species as optimal development of an embryo occurs within a small temperature range [108,109]. Incubation behaviour has been associated with increases in serum prolactin level [110], which may contribute to the molecular pathways underlying these behavioural differences [111]. Similarly, disruptions to endocrine signalling may contribute to the correlations observed between toxicant blood concentrations of Glaucous gulls and non-incubating time away from the nest, as suggested by the authors [94,95].…”

Effect of Sexual Deprivation Stress on Bone of Albino Female Rats

“…Also, [12] reported that, cold stress exposure in female mice terminated egg laying, induced ovarian regression, reduced plasma luteinizing hormone and ovarian steroids include estrogen and progesterone. Also, [13] reported that, estrogen production by granulose cells and the plasma concentration of estrogen in heat stressed goat was significantly lower within 36-54 hours than non stressed goats, while the concentration of follicle stimulating hormone (FSH) and progesterone showed no changes between stressed and non stressed goats.…”

Hormonal and neural correlates of care in active versus observing poison frog parents

“…A fundamental question left open by heavily female biased parental care research is how sex differences in offspring care arise and evolve. Despite marked sex differences in behavior, the neural circuits governing parental care appear largely conserved across sexes Pereira and Ferreira, 2016), as are the expression patterns of key neuromodulators, such as galanin Wu et al, 2014) and prolactin (Angelier et al, 2016;Angelier and Chastel, 2009;Hashemian et al, 2016). Some sex-typical care behaviors are linked to differences in circulating hormone levels (Adkins-Regan, 2005), expression of key signaling molecules (Albers, 2015), and variations in receptor distributions in the brain (Dumais and Veenema, 2016).…”