Local adaptation in trait-mediated trophic cascades.

Area of Science:

• Marine ecology
• Trophic dynamics
• Eco-evolutionary processes

Background:

• Predator-induced prey behavior influences community structure through trait-mediated trophic cascades.
• The role of basal resource availability in shaping these cascades is understudied.
• Eco-evolutionary dynamics between predators and prey can modify cascade strength.

Purpose of the Study:

• To investigate how basal resource availability influences predator-prey interactions and trait-mediated trophic cascades.
• To test if prey adaptation to resource scarcity affects their response to predation risk.
• To examine geographical variation in snail (Nucella lapillus) foraging behavior.

Main Methods:

• Field and laboratory experiments using Nucella lapillus from two Gulf of Maine regions with differing mussel abundance.
• Assessing snail foraging behavior on mussels in the presence and absence of predator (Carcinus maenas) risk cues.
• Measuring snail foraging and growth rates under varying predation risk and environmental conditions.

Main Results:

• Northern Gulf of Maine snails, with scarce mussels, showed reduced response to predator cues and increased response to temperature in field studies.
• In laboratory settings, northern snails exhibited higher foraging and growth rates when exposed to predator risk compared to southern snails.
• Foraging and growth rates were similar between northern and southern snails when predator risk was absent.

Conclusions:

• Geographical variation in basal resource availability may drive adaptive differences in prey behavior.
• Adaptation to resource scarcity can alter the strength and nature of trait-mediated trophic cascades.
• Understanding prey-resource dynamics is crucial for predicting marine community responses to environmental change.