Global change is known to affect species distribution. Understanding the resulting physiological responses of organisms is critical for predicting community composition changes that may occur under current and future conditions. The porcelain crab, Petrolisthes cinctipes, resides in the upper to mid intertidal zone and is expected to respond to rising temperatures by shifting its distribution lower in the cooler intertidal zone, where they will experience higher densities. They will also interact more often with its congener, Petrolisthes manimaculus. In this study, I addressed how increased density, species interactions (inter- and intra-), and increased temperature impact reproduction on P. manimaculus and P. cinctipes. This was indexed by circulating levels of the yolk protein vitellogenin (Vg). To address the variables, female crabs were exposed to high density (1000 crabs/m2) and low-density (333 crabs/m2) treatments with and without the presence of its congeneric species for 7 days. We found that interspecies interactions in high densities and increased temperature caused a downregulation of vitellogenesis in both P. manimaculus and P. cinctipes. These results demonstrate the transduction of climate change. Thermal stress in one species is being transduced onto another via increased density and competition in the rocky intertidal ecosystem.