Chronic Predation Risk Induces Sex‐Specific Effects in Behavior but Does Not Induce Long‐Term Oxidative Damage in the Threespined Stickleback

ABSTRACT Predation is a strong environmental and selective pressure that can favor rapid and plastic shifts in behavior and escape ability to increase an organism's immediate survival. However, maintaining antipredator responses under repeated predation stress can induce physiological costs to an organism from long‐term exposure to elevated cortisol. We know little about how individuals balance this trade‐off between short‐term survival and longevity, including whether males and females balance this trade‐off differently based on life history differences in reproduction, survival, and risk adversity. To assess sex differences in long‐term behavioral responses and physiological costs to predation risk, we exposed threespined stickleback ( Gasterosteus aculeatus ) to visual cues of a live rainbow trout ( Oncorhynchus mykiss ) predator twice a week for 14 weeks, then measured stickleback antipredator behavior and swimming performance 5 months later. To quantify potential long‐term costs of behavioral adjustments, we measured relative telomere length as a proxy for long‐term oxidative damage. We found strong sex specific effects in behavior and swim endurance: males, but not females, altered their hiding behavior and had shorter swim endurance in the first trial, suggesting overall lower activity. Surprisingly, we found no evidence for chronic predation shortening telomere length or hindering growth in body length. Overall, these results suggest that plastic responses can be dictated by the different life‐history strategies for males and females, and suggest that individuals can maintain long‐term changes in antipredator behavior without costs to their physiological state.