HUANG, H.-D.*; RITTSCHOF, D.; JENG, M.-S.: Chemical and visual cues used in crionoid host selection by symbiotic snapping shrimp

We hypothesized that obligate symbiotic snapping shrimp Synalpheus demani are able to locate and recognize crinoid hosts in a patched multi-species crinoid community. The present study tested S. demani’s responses to olfactory, visual and tactile cues from the host crinoid Comaster nobilis and non-host crinoids. Shrimp recognize hosts from non-hosts by odor in flow. In tests with visual targets, shrimp are attracted to large targets and move away from small ones. Host odor increases shrimp movement toward targets. Shrimp also respond to structure. They grasp mimics of the comb-like arms of C. nobilis. It appears S. demani first grasp objects with host arm structure and then confirm if it is the host by chemical cues. We conclude that large targets accompanied with host odor attract S. demani; the symbionts further discriminate the host via tactile and contact chemical cues.