Field studies on chemically mediated behavior in land hermit crabs: Volatile and nonvolatile odors.

Land hermit crabs,Coenobita rugosis, were tested in the field in Costa Rica for behavioral responses to odors. Volatile odors associated with horse feces, fruit, and honey attracted crabs within minutes. Odors from dead gastropod flesh were not immediately attractive, but after aging, odors from a variety of flesh sources attracted crabs. Crabs fed actively upon the materials that attracted them. Feeding behavior was stimulated by components of fruit juice and fresh gastropod flesh juices of less than 10,000 daltons, honey, a 0.5 M sucrose solution, and a saturated solution of tyrosine. Twenty additional amino acid solutions tested at 0.1 M concentration were weak feeding stimulants at best. Chemical cues controlled feeding behavior, but not shell acquisition;C. rugosis were not differentially attracted to flesh odors or to living gastropods whose shells they occupied.