Meeting Abstract
19.6 Friday, Jan. 4 Cardiac thermal tolerance and acclimatory plasticity in diverse populations of the invasive green crab, Carcinus maenas TEPOLT, CK*; SOMERO, GN; Stanford University; Stanford University carolyn.tepolt@gmail.com
Widespread invasive species successfully enter a broad range of novel habitats, often over short time scales, and exhibit remarkable abilities to thrive under new conditions, e.g., of temperature. These qualities make them ideal systems for examining traits underlying success in novel environments. Carcinus maenas, the green crab, ranges from Morocco to Norway in its native range and is globally invasive. Thus, this eurythermal species offers an opportunity to examine the thermal traits that facilitate success across a wide range of temperatures, and how those traits vary among populations of a widespread species. We characterized thermal tolerance and acclimatory plasticity for seven populations of C. maenas across 22 degrees of latitude in the native and invasive ranges. Using non-invasive cardiac physiology, we measured high and low temperature tolerance of cardiac activity (critical thermal maxima and heart rates at 0°C, respectively) for field-acclimatized crabs and for crabs given 3 – 4 weeks of laboratory acclimation at 5°C or 25°C. We show that the species has a high heat tolerance compared to other temperate species, with critical maxima of 30.8 – 37.0°C depending on source and acclimation. Both heat and cold tolerance were plastic; cold-acclimated crabs had heart rates at 0°C 3 – 5 times higher than their warm-acclimated counterparts. High and low temperature tolerances appear to be coupled, with higher heat tolerance accompanied by lower cold tolerance and vice-versa. We discovered some inter-population differences in thermal tolerance, potentially due to genetically different stocks. However, across all populations sampled, C. maenas maintains high thermal tolerance and acclimatory plasticity, even in populations with low genetic diversity due to sequential founding bottlenecks.
