| Summary: | Predators exert powerful influences on community structure through direct consumption and indirect predation risk that cascade down to lower trophic levels. However, predator effects are shifting in marine ecosystems due to global warming and ocean acidification, so predicting community-wide responses to climate change requires examining the physiological and behavioral mechanisms that drive changes in predator-prey interactions. In this dissertation, I developed a framework for understanding how warming and acidification can alter predator-prey interactions in oyster reefs by investigating the physiological and sensory-mediated behavioral responses of blue crab predators (Callinectes sapidus) and mud crab prey (Panopeus herbstii). First, I compared the physiological responses of blue crabs and mud crabs to warming and acidification. While survival of both species was negatively affected by the combination of warming and acidification, differences in metabolic responses suggest that mud crabs and blue crabs are differentially adapted to local environments that influence their responses to climate change. Next, I focused on the effects of warming and acidification on the chemosensory foraging behaviors of blue crab predators to attractive food cues using a two-channel choice flume. I found that warming slightly affected path kinematics of blue crab tracking behavior, but blue crabs maintained high success rates in tracking food cues regardless of temperature or pH stress, suggesting that their chemosensory function is robust to climate change. Finally, I investigated the effects of warming and acidification on the transmission and detection of blue crab predator cues that consequently suppress foraging behavior in mud crab prey, using either predator cues stressed in acidified conditions or prey stressed in warmed and acidified conditions. Warming constrained overall foraging activity of mud crabs regardless of predator cue, but acidifying the cue or the mud crabs did not affect this antipredator response. Thus, ...
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