A Possible Feeding Control Mechanism in Dungeness Crabs During Hyposaline Exposure

The Dungeness crab, Cancer magister, is classed as a weak osmoregulator. Nevertheless, this species will enter into low salinity regimes of estuaries during times of high food abundance. The present study investigated the possible regulatory role of neurohormones on feeding behaviour during acute low salinity exposure. When the crab's eyestalks were ablated, removing the terminal medulla and the associated X-organ/sinus gland complex, they consumed more food and fed for a longer period of time compared with intact animals. Eyestalk ablated animals would even attempt to feed in freshwater, whereas intact animals would only consume food in salinities above 40% SW. The results suggest that feeding behaviour during low salinity exposure in C. magister is regulated by an inhibitory neurohormonal mechanism. This mechanism may help animals balance the demands of competing physiological processes.