| My study was designed to determine how different thermal defense strategies and the intensity of high temperature challenges might affect demographic and physiological performance of limpets on rocky shores. Found together in the high intertidal zone, Lottia scabra employs a constitutive thermal defense strategy, whereas L. austrodigitalis has an inducible one. I measured loss and growth rates of both species as a function of average daily maximum temperature exposure in the field, and respiration rates for field-collected and lab-acclimated individuals under benign conditions in the lab before and after exposure to one of five peak temperatures (14, 24, 28, 32, or 36 °C) during a 4.5-hour simulated low tide. L. scabra was relatively unaffected by exposure to high temperatures, whereas L. austrodigitalis exhibited significant increases in loss rates from experimental plates, decreases in growth rates, and increases in oxygen consumption, consistent with activation of the heat shock response. |
