PHYSIOLOGICAL STRESS AND COLOR POLYMORPHISM IN THE INTERTIDAL SNAIL NUCELLA LAPILLUS

Area of Science:

• Marine biology
• Ecology
• Evolutionary biology

Background:

• Intertidal snail Nucella lapillus shows shell color variation linked to wave action.
• Populations on high-energy shores are polymorphic with pigmented morphs, while sheltered shores have white morphs.

Purpose of the Study:

• Investigate the roles of physiological stress and predation in maintaining Nucella lapillus shell color morph distribution.
• Determine if environmental factors or predation pressure drive observed color patterns.

Main Methods:

• Conducted field and laboratory experiments to assess physiological stress and predation.
• Tethered brown and white morphs in different microhabitats on exposed and protected shores.
• Monitored mortality rates under varying temperature and desiccation conditions.

Main Results:

• Physiological stress (heat, desiccation) is greater on protected shores.
• Brown morphs experienced higher mortality due to faster heating and desiccation than white morphs.
• Brown morphs had significantly higher mortality in sunny microhabitats on protected shores.

Conclusions:

• Interpopulation variation in Nucella lapillus shell color is partly driven by selective physiological stress.
• Predation by visual hunters did not appear to be a major factor for adults in this study.
• Further research on predation effects, especially on juveniles, is needed.