Revising the Role of Defense and Predation in Cone Snail Venom Evolution

Abstract

Venoms are widely employed by numerous animals across disparate lineages for predation and defense. Among them, the deadly carnivorous cone snails are reputed for the potency of their venoms comprising small neurotoxic peptides known as conotoxins. Though a majority of cone snails prey on worms, some species prey on fish and other mollusks despite being slow movers. This remarkable prey diversification contributes to their evolutionary success. The origins of these dietary shifts have historically been explained based on the synergistic pharmacology of toxin classes. However, the recent discovery that some mollusk-and fish-hunting snails inject distinct defensive and predatory venoms has led to an alternative hypothesis where defense plays a pivotal role in the evolution of conotoxins and cone snails. This chapter provides an overview of cone snails and highlights recent advances in our understanding of conotoxin evolution.