Amphipods on Sea Gooseberry (Comb Jelly)

A large number of crustaceans known as amphipods (mainly those in the Family Hyperiidae) are associated with gelatinous animals.  Hyperiid amphipods often have species-specific relationships, such that a particular species of amphipod may be found only on one or perhaps several related species of gelatinous zooplankton.  Medusae, siphonophores, ctenophores, pteropods and salps all serve as homes for these crustaceans.  The unfortunate comb jelly in the photo here (Hormiphora) is burdened by over a dozen of the pesky hitchhikers.  Often an amphipod will excavate a protective pit in the tissue of the host, or may be embedded deeper inside the animal.  Some living amphipods can even be found inside the stomachs of hydromedusae.  It's not clear if these amphipods typically consume host tissue and what other harm they may present.  With a load like the comb jelly pictured here, it would appear that there must be some disadvantage to hosting a throng of amphipods.  If disturbed excessively, hyperiid amphipods will swim away from the host and seek another gelatinous home.    

 All photographs in the JelliesZone © David Wrobel and may not be used or copied without permission!