MCA: how do early competitive interactions affect the development of the stress response?

The National Science Foundation awarded The University of the South $273,024 in a Project Grant on November 1, 2025, under the Biological Sciences program (CFDA 47.074) to investigate how early competitive social interactions shape development of the stress response.

The research examines whether competitive interactions early in life alter how individuals cope with stressors later, both behaviorally and hormonally, using genetically identical sibling fish to manipulate early competitive rank and observe consequences on stress hormone levels and future stress reactivity. The work supports training and mentorship of a mid-career investigator at this primarily undergraduate institution in hormone extraction techniques and modernizes data collection methods through an automated behavioral software program. Undergraduate students will receive hands-on training in behavioral and hormonal research methods and participate in new course offerings. Performance occurs at Sewanee, Tennessee, with period of performance from November 1, 2025, through October 31, 2028.

Abstract

The social environment that individuals experience during early life can affect brain development with long-lasting effects on behavior. Early competitive interactions in particular can determine an individual?S early access to resources, their circulating stress hormone levels, and their eventual dominance rank. However, whether these early interactions alter development of the stress response and how individuals react to future stressors remains unknown. This study will examine whether competitive social interactions early in life carry over to affect how individuals cope with stressors later, both behaviorally and hormonally. IT will support training and mentorship of a mid-career investigator at a primarily undergraduate institution to learn techniques in hormone extraction and allow the modernization of data collection methods with an automated behavioral software program. This support will also positively impact many undergraduate students who will be able to train in these behavioral and hormonal methods through hands-on research and new course offerings. Understanding how early social experiences shape an individual?S stress response can shed light on why there is so much variation among individuals in their resilience to stress. One explanation for why early social experiences have such broad behavioral consequences is that they alter the development of the neuroendocrine stress response. Because the neuroendocrine stress response enables individuals to react appropriately and habituate to stressors throughout their lives, experiences that have organizational effects on the brain and neuroendocrine system will likely have multiple downstream behavioral effects. The proposed project will manipulate early competitive interactions resulting in the formation of dominant and subordinate individuals in genetically identical sibling fish, and will examine the consequences of this experience on hormonal and behavioral plasticity across the lifespan of these individuals. This proposal will support a mid-career PI in (1) establishing a synergistic partnership with an endocrinologist who will provide valuable training in measuring water-borne glucocorticoid hormones and guidance in establishing a set-up to measure hormones at the PI?S primarily undergraduate institution, and (2) incorporating a software program to automate and standardize how the PI measures behavior on individuals through time. This proposal would integrate behavioral measures with the underlying hormonal mechanisms, and help US understand why early social experiences can have life-long consequences for an individual?S behavior. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are planned for this award.