Particle Selection in Suspension-Feeding Bivalves: Does One Model Fit All?

Area of Science:

• Marine Biology
• Animal Behavior
• Biochemistry

Background:

• Suspension-feeding bivalves exhibit selective particle ingestion, rejecting unwanted items as pseudofeces.
• The precise mechanisms of this selection, particularly the role of particle surface chemistry, remain incompletely understood.
• Previous research implicated carbohydrate-lectin interactions in mucus of oysters and mussels for particle selection.

Purpose of the Study:

• To investigate the role of carbohydrate-lectin interactions in food selection by bivalves with diverse gill architectures.
• To determine if cell surface carbohydrate profiles influence particle selection in clams (Mercenaria mercenaria) and scallops (Argopecten irradians).

Main Methods:

• Eight microalgae species with known surface carbohydrate profiles were cultured and harvested.
• Feeding experiments were conducted using pairs of microalgae presented to clams and scallops.
• Statistical decision tree models were developed to predict ingestion or rejection based on carbohydrate profiles.

Main Results:

• Microalgae abundant in mannose residues were preferentially ingested by both clams and scallops.
• N-acetylglucosamine residues influenced selection in scallops, while fucose residues played a role in clam selection.
• Carbohydrate profiles significantly predicted particle selection across different bivalve species.

Conclusions:

• Carbohydrate-lectin interactions are crucial for particle selection in suspension-feeding bivalves with varying gill structures.
• Mannose residues serve as a primary cue for ingested particle selection in these bivalves.
• This study elucidates conserved and divergent mechanisms of food selection in bivalves.