Exclusive male-female pairbonds (socially monogamous mating systems) are seen in only a few kinds of mammals and in some humans, but are a very common reproductive arrangement in birds. Yet almost nothing is known about the internal mechanisms (neurohormones, brain systems) for pairing in birds. Using a common laboratory species, the zebra finch, that forms long-lasting pair relationships, the project aims to discover these mechanisms as they operate at three different life stages to promote socially monogamous pairing: (1) early in life in nestlings when the strong tendency to form close affiliations with family members begins, (2) during juvenile life when the birds first become more interested in the opposite sex than in the parents, and (3) following adult loss of the mate (through death) when a new pair relationship with a new partner can occur. The project is aimed at determining the physiological mechanisms that promote these pair bonding behaviors. Experiments are designed to specifically test the potential involvement of neuropeptides, such as oxytocin, and the adrenal "stress" hormone, corticosterone, in facilitating pair bonding. The project will also investigate the role of corticosterone in the ability of the birds to remember and prefer their first partner even after a long period of separation. Overall, the project will solve a long-standing mystery "what makes birds like zebra finches form strong pair bonds?" It will suggest mechanisms that might apply to the thousands of other socially monogamous birds and more generally to other vertebrates. It will provide new information on mechanisms acting in birds that can be compared with mechanisms operating in socially monogamous mammals, and thus, has the potential to increase understanding of how brains and hormones produce close relationships in all animals, including humans. The project will provide training of students at all levels and will include specific activities to recruit and train women and underrepresented minorities for scientific research careers. The work will be disseminated to the public through general audience publications, a web site, and through outreach programs to middle school girls and local K-12 biology teachers.
