Vocal matching and intensity of begging calls are associated with a forebrain song circuit in a generalist brood parasite

• Published in: Developmental neurobiology (Hoboken, N.J.) N.J.), 2016-06, Vol.76 (6), p.615-625
• Main Authors: Liu, Wan‐Chun, Rivers, James W., White, David J.
• Format: Article
• Language: English
• Subjects: Age Factors; Analysis of Variance; Animals; Animals, Newborn; brood parasitism; brown‐headed cowbird; Feeding Behavior; food begging call; Foster Home Care; Gene Expression Regulation, Developmental - physiology; Immediate-Early Proteins - genetics; Immediate-Early Proteins - metabolism; Molothrus; Molothrus ater; Neural Pathways - physiology; Neurons - physiology; parental care; Prosencephalon - cytology; RNA, Messenger; Songbirds; vocal learning; Vocalization, Animal - physiology
• ISSN: 1932-8451; 1932-846X
• DOI: 10.1002/dneu.22348

ABSTRACT Vocalizations produced by developing young early in life have simple acoustic features and are thought to be innate. Complex forms of early vocal learning are less likely to evolve in young altricial songbirds because the forebrain vocal‐learning circuit is underdeveloped during the period when early vocalizations are produced. However, selective pressure experienced in early postnatal life may lead to early vocal learning that is likely controlled by a simpler brain circuit. We found the food begging calls produced by fledglings of the brown‐headed cowbird (Molothrus ater), a generalist avian brood parasite, induced the expression of several immediate early genes and early circuit innervation in a forebrain vocal‐motor pathway that is later used for vocal imitation. The forebrain neural activity was correlated with vocal intensity and variability of begging calls that appears to allow cowbirds to vocally match host nestmates. The begging‐induced forebrain circuits we observed in fledgling cowbirds were not detected in nonparasitic passerines, including species that are close relatives to the cowbird. The involvement of forebrain vocal circuits during fledgling begging and its association with vocal learning plasticity may be an adaptation that provides young generalist brood parasites with a flexible signaling strategy to procure food from a wide range of heterospecific host parents. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 615–625, 2016