Brightly coloured tissues in limid bivalves chemically deter predators

Area of Science:

• Marine Biology
• Chemical Ecology
• Bivalve Research

Background:

• Marine bivalves, particularly the Limidae family, exhibit vibrant coloration.
• The adaptive significance of these bright colors in bivalves remains largely unexplored.
• Predator-prey interactions are key drivers of evolutionary adaptations in marine ecosystems.

Purpose of the Study:

• To investigate the defensive role of colorful tissues in the 'disco' clam, *Ctenoides ales*.
• To determine if the bright coloration serves as a chemical defense mechanism against predators.
• To compare the chemical composition of colorful and non-colorful tissues.

Main Methods:

• Behavioral assays involving the peacock mantis shrimp (*Odontodactylus scyllarus*) and *Ctenoides ales*.
• Predator preference tests to assess consumption of different clam tissues.
• Mass spectrometry-based metabolomic analysis to compare tissue chemical profiles.

Main Results:

• *Ctenoides ales* exposed brightly colored tissues when attacked by the peacock mantis shrimp.
• Predators significantly preferred to consume non-colorful internal tissues over colorful external tissues.
• Metabolomic analysis revealed distinct chemical compositions between colorful and non-colorful tissues, with peptide-like compounds identified in colorful tissues.

Conclusions:

• Colorful bivalve tissues function as a chemical defense against predators.
• The distinct metabolomic profiles suggest a specialized defensive role for colorful tissues.
• This study provides the first evidence of colorful tissues being utilized for chemical defense in bivalves.