Do the ecological and social environments impair or improve phenotype?
Early experiences can shape adult social phenotype
The identification of appropriate companions and mates is essential to survival and reproduction. In many birds, social assortment is mediated by vocalizations learned through imitation. When imitative vocal learning occurs throughout life, emergent shared signals reflect current social associations. However, when vocal and genetic variation arises among populations, shared learned signal variants have potential to reflect cultural or genetic origin and to limit social and reproductive intermixing, provided that signal learning occurs prior to dispersal.
Developmental stress, behavior and the brain
Environmental conditions early in development are known to impact learning through organizational effects on the brain. In the extreme case, developmental challenges such malnutrition and exposure to pathogens or toxins can impair learning throughout life. On-going work in the Sewall lab is examining how environmental contaminants such as lead and mercury, postnatal nutrition, and early life infection may impair learning by interfering with postnatal brain development. Song learning in birds provides an excellent opportunity to pursue these questions because this form of learning occurs during a critical period early in life and is underpinned by neuronal growth within a specific neural circuit.