Meeting Abstract

P3.93  Saturday, Jan. 5  Morphological and behavioral determinants of thermal stress in northeastern Pacific Littorina. MILLER, L.P.; Hopkins Marine Station, Stanford University millerlp@stanford.edu

Snails in the genus Littorina are found in the mid and upper intertidal zones along much of the coast of North America. They are often the highest living marine organisms on the shoreline, and as a result are subjected to thermal stresses which can approach their lethal limits. Using a heat budget model and field measurements of body temperatures, I have made comparisons of the effects of morphology and behavior on body temperatures within and among four species of Littorina. Variation in shell shape, size, and color can lead to differences of up to 2°C under extreme conditions. Behavioral choices can also produce temperature differences of the same magnitude, and some combinations of morphology and behavior can lead to predicted body temperature differences of up to 5°C under the same environmental conditions. For snails living at the upper limit of the marine realm, these mechanistic models demonstrate that phenotype and behavior can be major drivers of physiological stress.