Mw. Grove et Sa. Woodin, CONSPECIFIC RECOGNITION AND HOST CHOICE IN A PEA CRAB, PINNIXA-CHAETOPTERANA (BRACHYURA, PINNOTHERIDAE), The Biological bulletin, 190(3), 1996, pp. 359-366
The pea crab Pinnixa chaetopterana (Brachyura: Pinnotheridae) lives in
the tubes of the host polychaetes Chaetopterus variopedatus and Amphi
trite ornata. While attraction to host odor cues is common in symbiote
s, P. chaetopterana resident in Chaetopterus tubes apparently show no
attraction to water-borne cues from either host. Because crabs residen
t in Amphitrite tubes are significantly reduced in their maximum body
size and thus clutch size, switching between hosts should occur. We th
erefore tested the hypothesis that the crabs use odor cues from conspe
cifics or from the competing crab Polyonyx gibbesi (Anomura: Porcellan
idae) when locating a new host. Crabs collected from Amphitrite are si
gnificantly attracted to Chaetopterus hosts which contain a mixed sex
pair of conspecifics. Females show a strong tendency to avoid hosts co
ntaining Polyonyx, but males do not. Neither sex is attracted to unocc
upied Chaetopterus or Amphitrite hosts, but both are significantly att
racted to isolated conspecifics. This attraction could serve as a reli
able means of locating suitable new hosts when switching hosts in the
field. Attraction to conspecific odors would also increase the chances
of finding a suitable mate already present in a new host.