Predator Non-consumptive Effects on Prey Recruitment


  • Julius A. Ellrich,

  • Ricardo A. Scrosati,

  • Markus Molis

All photographs by R. A. Scrosati

Predators may have nonconsumptive effects (NCEs) on prey populations mediated by chemical cues detected by prey. We experimentally investigated dogwhelk (Nucella lapillus) NCEs on intertidal barnacle (Semibalanus balanoides) recruit density in Nova Scotia, Canada. Under a moderate abundance of coastal phytoplankton (food for barnacle larvae and recruits), barnacle recruitment was moderate and the nearby presence of dogwhelks limited barnacle recruit density at the end of the recruitment season. Under a high phytoplankton abundance, barnacle recruitment was high and neutralized dogwhelk NCEs on barnacle recruit density, likely through the chemical attraction that recruits exert on larvae seeking settlement.

Figure Photo 1.

Barnacle recruits and predatory dogwhelks on the Atlantic coast of Nova Scotia, Canada. Photograph by R. A. Scrosati.

Figure Photo 2.

Julius Ellrich and experimental cages used to study the nonconsumptive effects of predatory dogwhelks on barnacle recruitment.

These photographs illustrate the article “Predator nonconsumptive effects on prey recruitment weaken with recruit density” by Julius A. Ellrich, Ricardo A. Scrosati, and Markus Molis, published in Ecology 96(3):611–616.