Investigating relationships among stress, reproduction, and immunity in three species of watersnake

• Published in: General and comparative endocrinology Vol. 343; p. 114350
• Main Authors: Field, Emily K., Terry, Jennifer, Hartzheim, Alyssa M., Krajcir, Kevin, Mullin, Stephen J., Neuman-Lee, Lorin A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-11-2023
• Subjects: Bacterial killing ability; Corticosterone; Energy; Squamata; Tradeoffs; Vitellogenesis; Squamata; Vitellogenesis; Energy; Corticosterone; Tradeoffs; Bacterial killing ability
• ISSN: 0016-6480; 1095-6840
• DOI: 10.1016/j.ygcen.2023.114350

•Energy is a finite resource and must be allocated among important physiological processes such as reproduction, the stress response, and immunity.•Snakes exhibit a wide variety of reproductive strategies and provide a unique study organism.•Timing of the acute stress response shifts throughout the breeding season.•Snakes appear to prioritize reproduction over immunity during energetically expensive processes such as vitellogenesis.
Energy is a finite resource required for all physiological processes and must be allocated efficiently among essential activities to ensure fitness and survival. During the active season, adult organisms are expected to prioritize investment in reproduction over other energetically expensive processes, such as responding to immunological challenges. Furthermore, when encountering a stressor, the balance between reproduction and immunity might be disrupted in order to fuel the stress response. Because of the distinct differences in life histories across species, watersnakes provide a unique group of study in which to examine these tradeoffs. Over a two-year period, we captured three watersnake species throughout Northeast Arkansas. Animals were subjected to restraint stress and blood samples were collected throughout the acute stress response. Blood samples were used to assess innate immunity and steroid hormone concentrations. We found the peak in corticosterone concentration is season-specific, potentially because energetic reserves fluctuate with reproductive activities. We also found body condition was positively related to acute stress and negatively related to immunity. Watersnakes evidently prioritize reproduction over immunity, especially during the energetically intensive process of vitellogenesis. Energetic tradeoffs between reproduction, immunity, and the stress response are complex, and this study contributes to our understanding of energetic shifts in free-living organisms in the context of stress.