Local selection and latitudinal variation in a marine predator-prey interaction

Area of Science:

• Marine Ecology
• Population Genetics
• Behavioral Ecology

Background:

• Species interactions are fundamental to community structure, but how they vary across large geographic scales remains understudied.
• The Pacific coast of North America hosts extensive intertidal communities with potential for large-scale ecological processes.

Purpose of the Study:

• To investigate spatial variation in predation rates between the snail Nucella canaliculata and the mussel Mytilus californianus along the Pacific coast.
• To determine the role of genetic factors and gene flow in shaping these interspecific interactions across large distances.

Main Methods:

• Conducted field surveys along 1500 km of the Pacific coast to quantify predation frequencies.
• Performed laboratory rearing experiments to assess the genetic basis of snail drilling behavior.
• Analyzed mitochondrial DNA sequences to evaluate gene flow among Nucella canaliculata populations.

Main Results:

• Significant regional variation was observed in the frequency of Nucella canaliculata preying on Mytilus californianus.
• Laboratory experiments indicated a genetic component to regional differences in snail drilling behavior.
• Mitochondrial sequence data revealed low gene flow between geographically separated snail populations.

Conclusions:

• Marine communities separated by hundreds of kilometers can exhibit intrinsically different ecological dynamics.
• Restricted gene flow and spatially varying selection are key factors shaping predator-prey interactions in marine ecosystems.
• Understanding large-scale spatial variation is crucial for predicting marine community responses to environmental change.