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Tracking a Shape Shifter: Relating Host Association and Phenotypic Plasticity to Flow in an Epizoic Barnacle

John Zardus, The Citadel

8 September 2017

Phenotypic plasticity is the capability for one genotype to produce multiple phenotypes under different environmental conditions. Barnacles, living permanently fixed in place as adults, appear in many instances to compensate for their sessile lifestyle through plastic responses to dissimilar regimes of water flow, crowding, and predation. Species of barnacles that are epizoic commensals of mobile hosts, while in part escaping a completely sessile fate, face the challenge of variable environmental conditions, depending on the behavior of their host. In general, epizoic barnacles tend to have narrow host ranges, associating with one or only a few closely related host species. However, the barnacle Chelonibia testudinaria exhibits relatively low host fidelity, but, disguised by phenotypic plasticity. Initially considered a ‘turtle’ barnacle, it is now known to also occur on crabs and manatees in altered form. In this presentation Dr. Zardus will describe uncovering the deception in this species genetically along with innovations in laboratory studies using revolving pipes to investigate potential causes of its shape shifting abilities.