Heterophil/Lymphocyte Alterations as a Measure of Stress in American Alligators in Relation to Anthropogenic Disturbance in a Louisiana Intermediate Marsh

Abstract

Numerous anthropogenic factors represent environmental threats to Gulf Coast wetland ecosystems and associated fauna. American alligators (Alligator mississippiensis) have been subject to long-term management and used as ecological and physiological indicators of habitat quality in response to anthropogenic events and stochastic natural disasters. The present study monitored heterophil to lymphocyte ratios (an indicator of stress), in American alligators in a Louisiana intermediate marsh from 2009 to 2011, a time period that coincides with an oil inundation event that occurred in 2011. Sixteen alligators were observed and processed morphometrically (total length, snout-vent length and body mass). Heterophil to lymphocyte ratios were negatively correlated with size, suggesting larger American alligators were physiologically more resilient to the disturbance, more able to actively avoid these poor conditions, or are less affected by localized disturbance.

Testing androgen‐induced immunosuppression: Environmental androgens as a model system for steroid‐immune interaction

“…Stressful conditions elevate levels of circulating glucocorticoids which are known to alter physiology such as shifting the profiles of circulating heterophils and lymphocytes (Sapolsky et al, 2000). Thus, we may consider the low H:L present in our alligators to indicate that these animals did not experience chronically stressful conditions (Lance et al, 2010; Murray et al, 2015), which may alter immune function (Sapolsky et al, 2000).…”