HUANG, H.-D.; RITTSCHOF, D.; JENG, M.-S.; Duke Univ.; Duke Univ.; Academia Sinica, Taiwan: Crinoid host selection by the symbiotic snapping shrimp Synalpheus demani

The crinoid Comanthina schlegelii occurs in patchy multispecies crinoid communities. In Taiwanese waters, snapping shrimp Synalpheus demani is an obligate symbiont of C. schlegelii. We hypothesized that S. demani use chemical and tactile cues to locate and recognized its host. In laboratory studies, we tested S. demani�s responses to olfactory and tactile chemical cues from the host Comanthina schlegelii, non-host crinoids, an urchin, and a branch coral. Shrimp responded only to host odor. In tests with host cues, male shrimp showed two levels of responses. Females responded only to higher concentrations. At least one attractive cue is volatile. Gas chromatography / mass spectrometry indicated the volatile cue may be long chain alcohol. Shrimp also respond to structure and contact chemicals. In the dark, shrimp grasped living crinoid arms and arm mimics soaked in host odor. We conclude that S. demani move toward host chemicals and confirm the host via tactile and contact chemical cues.