Marine Biology

, Volume 38, Issue 4, pp 365–372 | Cite as

Incidence, reproduction and feeding of Stylochus zebra, a polyclad turbellarian symbiont of hermit crabs

  • M. W. Lytwyn
  • J. J. McDermott


The hermit crab Pagurus pollicaris is the common host for the polyclad turbellarian Stylochus zebra in the Atlantic coastal waters from Massachusetts to North Carolina, USA. S. zebra is reported for the first time from two other hermit crabs, Pagurus impressus and Petrochirus diogenes. It was not found with Clibanarius vittatus or Pagurus longicarpus, although the latter serves as a host along the Gulf coast of Florida. The incidence of the polyclad with P. pollicaris in Massachusetts is more than twice that in populations to the south. Multiple infestations (up to 7 worms/crab) occur in over 50% of the infested crabs from Massachusetts, but they are rare elsewhere. Worms living in clear plastic shells with crabs orient in the body whorl dorsal to the host. Egg masses of worms are cemented in the same position within gastropod shells harboring the crabs. In the laboratory, the worm feeds on the gastropod Crepidula plana, a common inhabitant of shells occupied by P. pollicaris. Its feeding behavior is described. The relationship between S. zebra and P. pollicaris appears to be generally commensalistic, but it could be more complicated if the predation of crab embryos observed in the laboratory is confirmed under natural conditions.


Natural Condition Coastal Water Feeding Behavior Gulf Coast Hermit Crab 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • M. W. Lytwyn
    • 1
  • J. J. McDermott
    • 2
  1. 1.Department of ZoologyUniversity of North CarolinaChapel HillUSA
  2. 2.Department of BiologyFranklin and Marshall CollegeLancasterUSA

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