27.2 Wednesday, Jan. 4 Color-polymorphism in the Green Crab, Carcinus maenas: Are green morphs really more stress tolerant than red morphs? FREDERICH, M.*; TOOMBS, C.; PENNOYER, K.; Univ. of New England, Biddeford; Univ. of New England, Biddeford; Univ. of New England, Biddeford email@example.com
Despite the name green crab, this species shows carapace coloration from bright green to dark red. Crabs are green after molting, delayed molting leads to darker red shades. Earlier work investigating organismic parameters suggests that the color-polymorphism is mirrored by physiological polymorphism, with green morphs more anoxia, hypoxia, and salinity tolerant. We tested the hypothesis that differential organismic stress tolerance is reflected in cellular stress parameters and ion transporters. Red and greens were exposed to 2h anoxia, 24h hypoxia or 72h low salinity (10ppt) stress. We analyzed at the organismic level treadmill running endurance, O 2 consumption, and heart rate, on the cellular level lactate accumulation, AMPK and HSP70 activity and mRNA expression in heart tissue, as well as ion transporters (mRNA and protein levels) in gills. At the organismic level under normoxic conditions no differences were found between red and greens. During anoxia red and greens did not differ in their organismic response, but greens showed elevated lactate, AMPK activity and HSP70 protein. During hypoxia, reds had reduced running endurance and increased HSP70 protein, but greens had higher lactate and AMPK activity. No differences were found in AMPK or HSP70 mRNA expression. During low salinity stress mRNA levels of NaK-ATPase, NaK2Cl-cotransporter, NaH-exchanger, carbonic anhydrase, AMPK and HSP70 showed differential expression, matching organismic parameters, and indicating that greens are more salinity tolerant. The data show color morph-specific stress tolerance, but greens are not generally more stress tolerant than red morphs. Funded by NSF-IOB0640478 and an APS summer research award.