DOI: 10.5061/dryad.30hg1
title: Data from: Thermal sensitivity and the role of behavior in driving an intertidal predator-prey interaction

description: Environmental stress models (ESM) provide a useful framework to study the
 direct and indirect ecological drivers of community diversity and
 resilience. ESMs make predictions about the relative importance of
 structuring processes (e.g., predation) based on the relative stress
 suffered by consumers and prey. Their practical application, i.e.,
 determining the conditions under which consumers and prey performance is
 more negatively affected, has been limited because the roles of behavior
 and physiology are not usually considered. We examined the role of thermal
 sensitivity and behavior on the thermal performance of the rocky
 intertidal predator Pisaster ochraceus and its main prey Mytilus
 californianus. We propose a novel framework that merges thermal
 performance curves (TPC) with observations of microhabitat use to provide
 a realistic perspective of the relative physiological conditions of
 predator and prey. First, by deriving aquatic and aerial TPCs for both
 species and from two sites, we found differences in parameter values that
 in some cases correspond to the individuals’ origins. Second, we
 calculated realized thermal performance in the field by combining TPCs
 with body temperatures recorded with biomimetic sensors. Notably, thermal
 performance of Pisaster was higher than that for Mytilus (i.e.,
 prey-stress model), contrary to previous expectations based on caging
 experiments. Third, these estimates of thermal performance corresponded
 loosely with a measured indicator of overall physiological condition (body
 mass index, BMI) and a marker for extreme thermal stress (heat-shock
 proteins 70 kDa), suggesting that environmental drivers other than
 temperature, such as food supply, must be considered. We found no evidence
 that Pisaster movement significantly influences thermal performance under
 typical conditions, suggesting instead that its preference for sheltered
 microhabitats provides a mechanism for avoiding exposure to extreme
 environmental conditions. Through the application of TPCs and ESMs, this
 study provides a unique perspective on the importance of physiology and
 behavior in driving the sensitivity of species interactions to
 environmental change. Crucially, this framework allowed clarifying that
 this system behaves as a prey- instead of consumer-stress model, which may
 also apply to many other ectotherm species interactions.
description: Biomimetics_Temperatures_Fig1Pisaster ochraceus and Mytilus californianus biomimetic temperatures recorded in the mid intertidal zone at Bodega (California) and Strawberry Hill (Oregon) during summer months of 2012 (June 22nd through August 10th). Data were collected every 30 min.Pisaster_Mytilus_SMR_Fig2Standard metabolic rate (SMR) of the sea star Pisaster ochraceus and mussel Mytilus californianus collected from Bodega (California) and Strawberry Hill (Oregon).Estimated_relative_performance_Fig3Aquatic and aerial thermal performance curves described for Pisaster ochraceus and Mytilus californianus from Bodega (California) and Strawberry Hill (Oregon). We estimated the aquatic curves’ parameters using empirical SMR measurements (Pisaster_Mytilus_SMR_Fig2), and the aerial curves’ parameters using information from the literature.Calculated_relative_performance_Fig4Thermal performance calculated for Mytilus californianus (prey) and Pisaster ochraceus (predator) using species- and site-specific thermal performance curves and body temperatures recorded in situ by biomimetic sensors. The static scenarios represent individuals that remain immobile. The mobile predator considers movements between microhabitats, as informed by regular surveys of microhabitat use. The optimal scenario represents the hypothetical situation where Pisaster occupies the microhabitat that reports the highest performance.Body_mass_index_Fig.5Body mass indices (BMI) of Pisaster ochraceus and Mytilus californianus individuals collected at Bodega (California) and Strawberry Hill (Oregon) during the summer of 2012.Hsp_temperature_Lab_Fig.6Total heat shock protein 70kDa (Hsp70) expression (i.e. constitutive and inducible isoforms are not differentiated) measured from Pisaster ochraceus tube feet and Mytilus californianus gill tissues. Tissues were sampled after individuals had been kept at one of six seawater temperature treatments (10, 13, 18, 21, 24, and 27˚C) for 4d.Hsp_date_Field_Fig.6Total heat shock protein 70kDa (Hsp70) expression (i.e. constitutive and inducible isoforms are not differentiated) measured from Pisaster ochraceus tube feet and Mytilus californianus gill tissues. Tissues were collected in the field at low tide and immediately frozen in dry ice.