Charlotte Regula

Spiralzooid Form and Function within Hydractinia Spp. Colonies Encrusting Pagurus Hermit Crab Shells.

Charlotte's research interests involve issues of zooid polymorphism and hydroid colony structure.  Her thesis focuses on a mechanistic approach to understanding first why spiralzooids only form the apperayre of a hermit crab occupied shell, in order to next understand spiralzooids potential function as protective zooids within a colony.

Discarded gastropod shells act as essential resources in benthic marine communities, particularly in intertidal zones where sources of stable hard substrate are scarce and the potential for desiccation is high.  Competitive interactions in these systems tend to produce symbiotic relationships between those organisms that use shells as attachment substratum (eg. Hydrozoans) and those that use them as sources of refuge (eg. Hermit Crabs).  Specialization in zooid form and extensive colony plasticity has elevated hydrozoan colonies' dominance over other encrusting phyla, such as Ectopracta, Annelida, and Mollusca, by allowing them to adapt more rapidly to their turbulent environments.  Division of labor between zooid types, coupled with uneven zooid distribution, has resulted in zooids interacting differently within the shell communities.  Although spiralzooid interactions with hermit crabs and other epibionts have been studied, we still do not know how spiralzooids form or function and what effect they have on benthic marine community composition.

If you would like more information about the project, please email Charlotte at