Meeting Abstract
One of the driving forces of marine biodiversity is predation pressure. The marine bivalve family Limidae is an ideal study system to address this topic. Members of this family have evolved numerous means of predator defenses, including aposematism (warning coloration), flashing displays, tentacle autotomy, and escape swimming. To further characterize defense mechanisms in this family, chemical defenses in the genus Ctenoides were examined through behavioral studies and metabolomics. Potential predators of Ctenoides were exposed to external (tentacles, mantle) and internal (adductor muscles) bivalve tissues to conduct food choice trials. Predators actively avoided external tissues, including removing them from burrows. Comparative metabolomics analysis was conducted using reverse phase ultra-high pressure liquid chromatography (UHPLC) coupled to time of flight (TOF) mass spectrometry (MS) to evaluate chemical compounds present in potentially distasteful tissues versus edible tissues. The analysis revealed that distasteful and edible tissues have significantly different chemical compositions. Over 1400 chemical compounds were detected in the two types of bivalve tissues, among which nearly 600 have significantly higher concentrations in distasteful tissues. These compounds included many peptides, which may potentially be responsible for the chemical defenses in Ctenoides. Future work also aims to utilize comparative phylogenetics to develop a complete understanding of the evolution of defenses within Limidae.
