Meeting Abstract

P1.137  Friday, Jan. 4  Variation in thermal tolerance between life stages of the intertidal copepod Tigriopus californicus KIM, T.L.*; NEUFELD, C.; Northwestern University; University of Washington tk12@u.northwestern.edu

Predicting the impacts of climate change on species ranges is essential for global conservation efforts. Recent studies suggest thermal tolerance can vary considerably among geographically isolated populations within a single species. However, it is not clear whether similar variation in heat tolerance exists between life stages of organisms with complex life cycles. In this study, we test the thermal tolerance (LT₅₀) of each life stage in five populations of copepod Tigriopus californicus, spanning 18 degrees in latitude. Copepodites (juveniles) were able to tolerate 1-2°C higher temperatures than adult males or females within four of the five populations, on average. Furthermore, across all life stages, the southernmost population exhibited a 2°C higher heat tolerance than the least-tolerant population. The presence of biologically significant variation in thermal tolerance across some (but not all) populations and life stages suggests both factors should be included when forecasting climate change impacts on species ranges.