Award: OCE-1948423

The goal of our project was to identify the specific molecules that prey utilize to assess predation risk and to explore whether these molecules differ among various predator species or guilds and prey taxa/trophic level. To date, we have demonstrated that urine from four predators: sheepshead, black drum, blue crabs, and stone crabs, induces mud crabs (intermediate predators) to reduce their foraging rates and prompts oysters (basal resources) to develop heavier, stronger shells.

Employing a metabolomics approach, we have successfully identified four key molecules that constitute a fear signal emitted by these predators, which in turn alters the behavior and morphology of their prey. These molecules are the products of general metabolism and therefore might be commonly produced by many predators.  These molecules often are present in high concentration in urine released by predators, and are sometimes, but not always, enhanced when predators eat oysters. We have invented new techniques for collecting urine from these predators and developed novel chemical methods for identifying the molecules present in chemically complex urine that influence prey traits.

Our findings hold significant implications for basic research, particularly in understanding how fear influences species interactions within food webs and how prey respond to the evolutionary pressures related to the detection of potential predatory threats. Our findings of relative commonness, high concentration and diet dependence may suggest general characteristics of water borne molecules of fear that are similar to those identified in the waste of terrestrial carnivores that also act as fear signals.

 Moreover, our results have practical applications in enhancing oyster aquaculture and restoration efforts. In both aquaculture and restoration facilities, caged predators are utilized to stimulate oysters to grow harder shells, thereby increasing their ability to deter predators and enhancing their overall survival. Hardened oysters survive better in the field in a variety of conditions suggesting their use in reef restoration and living shorelines may improve conservation efforts and erosion management. However, the chemicals identified here can be used to produce synthetic cocktails that could be applied easily to enhance the survival of oyster spat in the field and harden them against wave exposure.

 

Last Modified: 05/01/2026
Modified by: Marc J Weissburg