Thesis

Effects of thermal stress on vitellogenin levels in the hemolymph of the anomuran crab petrolisthes cinctipes

Intertidal organisms, like the porcelain crab, regularly experience thermal stress. Petrolisthes cinctipes inhabits the upper-mid intertidal zone and is often exposed to aerial stressors at low tide. Increased abiotic stressors may interfere with many aspects of this organisms’ physiology, including reproduction. Reproductive activity can be measured through the quantification of the yolk protein vitellogenin (Vg), found in hemolymph. ELISA for P. cinctipes allowed for quantification of Vg in hemolymph. Vg sampling of P. cinctipes revealed decreased reproduction around the summer solstice. Reproduction may be dependent on environmental variables such as temperature or day length. To examine this, P. cinctipes were collected monthly for one year. After a pre-treatment hemolymph draw, crabs underwent treatment to test effects of long day lengths and daily exposure to thermal stress. After two weeks of treatment, a second hemolymph sample was drawn. Hemolymph samples were analyzed for Vg levels using an ELISA. Crabs collected near the summer solstice sustained low levels of Vg after exposure to thermal stress. Long day thermal stress conditions caused Vg production to decline in crabs collected during the winter solstice. These data suggest that P. cinctipes relies on multiple environmental cues in regulating reproduction, and changes in environmental conditions could interfere with this physiological process.

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