Catching a ride snail-style symbiotic interactions between the snails Crepidula convexa with their hermit crab and snail hosts


Meeting Abstract

P2.147  Wednesday, Jan. 5  Catching a ride snail-style: symbiotic interactions between the snails Crepidula convexa with their hermit crab and snail hosts IYENGAR, E.V.*; KONICKI, W.S.; VOLTZOW, J.; Muhlenberg College; Muhlenberg College; University of Scranton iyengar@muhlenberg.edu

Symbiotic associations are likely to drive the evolution of one, if not both, partners. Marine snails in the genus Crepidula are suspension feeders and many form long-term interactions with hosts. Individuals of the epibiotic slipper limpet Crepidula adunca in Washington State prefer to live on the shells of top snails (Calliostoma ligatum) in the intertidal (>95% of the population), are rarely located on shells occupied by hermit crabs, and are never found living independently. Large infestations of Crepidula adunca (representing >10% of the host’s mass) negatively impact the running and righting speeds of the snail host. In a parallel system in Sandy Hook, New Jersey, members of the epibiotic species Crepidula convexa (>95% of the population) utilize hermit crabs (Pagurus longicarpus) residing in the shells of the gastropod Ilyanassa obsoleta as hosts and rarely live independently on rocks or snails, even though living snail hosts are abundant. Large infestations of epibiotic Crepidula convexa do not affect righting time for their host hermit crab. In choice experiments, individuals of Crepidula adunca choose Calliostoma ligatum snails more often than any other potential host, including hermit crabs in shells of Calliostoma ligatum. In contrast, in similar experiments, individuals of Crepidula convexa utilize hermit crabs and empty I. obsoleta shells as hosts more often than living snails. Adults of both species of Crepidula typically reside in the same sector on the host’s shell in a similar orientation, regardless of the species of host used. Juveniles of Crepidula adunca, on the other hand, tend to utilize the underside of the entire body whorl. Comparisons between these two systems may provide insights into the evolution of symbiotic interactions.

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