Intracapsular development and dispersal polymorphism in the predatory gastropod Ocenebra erinaceus (Linnaeus 1758)

Intraspecific polymorphism during development, such as poecilogony or dispersal polymorphism, has rarely been observed in the marine environment. The ecological advantages of this bet-hedging strategy, whereby the offspring from one species exhibit multiple developmental modes, include the potential for rapid colonization of new habitats whilst simultaneously achieving a degree of gene flow between populations. The muricid gastropod, Ocenebra erinaceus, is an active predator that is common in shallow-water marine environments, across England and France. Historically, O. erinaceus caused significant damage to shellfisheries but more recently it has been impacted by TBT induced imposex. Despite the previous attention given to this species, little is known about its encapsulated development. Studying O. erinaceus egg capsules from the Solent, UK, we describe intracapsular development at 15 °C, the in situ temperature at time of oviposition. Within each capsule all embryos developed; no nurse eggs were present. Development was categorised into eight ontogenetic stages, although not all individuals displayed every stage; embryos hatched as either swimming, late-pediveliger larvae or crawling juveniles after 59–69 days, indicating dispersal polymorphism to occur in this species. Swimming, late-pediveliger larvae completed metamorphosis within 72 h of hatching. As O. erinaceus continues to recover from TBT pollution, dispersal polymorphism may facilitate a rapid expansion in both population size and range. If this occurs, O. erinaceus has the potential to, once again, become a serious problem for shellfisheries around Europe