Lamellose Axial Shell Sculpture Reduces Gastropod Vulnerability to Sea Star Predation.

Area of Science:

• Marine Biology
• Evolutionary Ecology
• Zoology

Background:

• Marine gastropod shell sculpture diversity is high, but its adaptive significance is often unclear.
• Experimental studies are confounded by interspecific morphological differences, necessitating intraspecific variation studies.
• Axial lamellae are common shell sculptures in marine gastropods, but their function is poorly understood.

Purpose of the Study:

• To investigate the adaptive significance of axial lamellae in the marine gastropod Nucella lamellosa.
• To determine if shell lamellae provide protection against predation by the sea star Pisaster ochraceus.

Main Methods:

• Utilized intraspecific variation in Nucella lamellosa shell forms (lamellose, artificially smooth, naturally smooth).
• Conducted controlled laboratory experiments offering three snail forms to predatory sea stars (Pisaster ochraceus).
• Quantified snail consumption rates by the sea stars.

Main Results:

• Pisaster ochraceus consumed significantly fewer lamellose Nucella lamellosa snails compared to artificially or naturally smooth snails.
• Lamellose shell sculpture significantly reduced predation rates by sea stars.

Conclusions:

• Shell lamellae likely deter sea star predation by hindering prey capture or manipulation, or by increasing effective prey size.
• Axial lamellae represent a key adaptation for predator defense in marine gastropods.
• These findings contribute to understanding adaptive phenotypic plasticity in Nucella lamellosa shell morphology.