Meeting Abstract
In Massachusetts, surface temperature and precipitation are both expected to increase in the coming years. For intertidal organisms, these changes will be felt most strongly in tide pools at low tide. A hot, sunny day will see rising temperatures and increasing salinity in a tide pool, while a rainy day will lower salinities. The hermit crab Pagurus longicarpus is found both intertidally and subtidally along the east coast of the U.S., and requires access to empty gastropod shells for protection. Studies have shown the limits of hermit crabs’ abilities to survive at temperature and salinity extremes, but how might rapid, non-lethal shifts in temperature and salinity affect their shell-selection behavior? We tested the effects of such changes (temperatures ranging from 14°C to 33°C and salinities ranging from 20 ppt to 40 ppt) on their ability to select high quality shells that would be most likely to protect them from predators and desiccation. Each crab was given a choice between an intact shell of ideal size, a shell of ideal size with a drill hole, and a shell ¾ of the ideal size. Trials were run in which the crabs began without shells, and also in which the crabs began in either drilled or small shells. Increasing the temperature from 21°C to 30°C had little effect on shell selection behavior, but increasing the temperature to 33°C had a noticeable effect: those crabs that managed to occupy the best shell took much longer to do so. Lowering the temperature had a noticeable effect when the crabs started off in the small shells, and raising and lowering the salinity had the strongest effect when crabs started off in drilled shells.
