Linking Inferred Laboratory-Derived Temperature Stress to the Immunocompetence of Wild Octopus maya (Mayan Octopus)...

The "oxygen capacity-dependent thermal tolerance" (OCLTT) hypothesis suggests that the ability of ectotherms to tolerate heat is limited by their ability to supply oxygen to their tissues at various temperatures set by the capacity of the cardiovascular and respiratory systems. Optimal temperatures and oxygen can supply enough energy through adenosine triphosphate (ATP) via the electron transport chain to support fitness-related processes. Conversely, stressful temperatures indicate an energetic limitation that could describe physiological parameters and biogeographical patterns. Our study aimed to determine if stressful temperatures could be related to immunological performance under a macroecological approach. To prove this hypothesis, we recapitulated key immune parameters, including total hemocyte count, hemagglutination, phenoloxidase system, and lysozyme activity, of wild mayan octopus (Octopus maya), an endemic species in Mexico's Yucatan Peninsula, with physiological data via thermal metabolic scope (a proxy of the aerobic scope) from its fishing regions. Our results indicate that stressful temperatures (> 27°C) are associated with depression in the immunocompetence of the mayan octopus. Specifically, we found that favorable temperatures (< 27°C) are positively correlated with a better immunocompetence of wild octopus. This study provides evidence that temperature stress inferred from laboratory studies presents a potential tool to determine wild populations' health. However, predictions and modeling should consider additional factors such as demographic distribution, seasonality, biotic/abiotic interactions, and ontogenetic development.