NEPHROPORE ROSETTE GLANDS OF THE LOBSTER HOMARUS AMERICANUS: POSSIBLE SOURCES OF URINE PHEROMONES

Abstract

ABSTRACT This study examined the nephropore area of sexually mature lobsters for the presence of structures capable of producing chemical signals in conjunction with urine release. Urine signals are used for chemical communication in the lobster Homarus americanus. Male urine plays a role in the determination of dominance and female choice of dominant males, while female urine reduces the incidence of male aggressive behavior and induces male mating behavior. Masses of rosette glands were found, lateral and medial to the ureter of all animals examined. Staining properties and gland morphology suggest that nephropore rosettes are active in males and females, in all molt stages and at all times of the year. Rosette glands stained positively for protein and mucopolysaccharides. Gland complexes did not show histochemical evidence of phenoloxidase, a product of some crustacean rosette glands. Nephropore rosette glands were packaged into clusters, which in turn were organized into lateral and medial gland complexes lying alongside each ureter. Complexes were joined by a common duct terminating at the bladder, while rosettes in some anterior clusters were served by individual ducts passing through the nephropore sphincter and terminating outside the animal adjacent to the site of urine release. These two duct systems could allow gland complexes to release their products into the environment with or without concomitant urine release, and as such these glands are good candidates for sources of chemical signals.