Release of Spawning Pheromone(s) by Naturally-Ovulated and Prostaglandin-Injected, Nonovulated Female Goldfish

Abstract

Although several studies have demonstrated the importance of smell in goldfish spawning behavior, they have not substantiated the release of a discrete odor signal, or pheromone, by recently ovulated females. Partridge et al. (1976) found male goldfish tested in a Y-maze preferred water in which ovulated females had been held. However, a preference was also exhibited toward food odor. When placed with ovulated and nonovulated females intact males interacted selectively with ovulated females, but olfactory-ablated males exhibited the same preference although to a lesser degree. Similarly, Stacey and Kyle (1983) found that while olfactory tract sectioning reduces male courtship behavior it does not eliminate it. Goldfish are attracted to conspecific odor (Le Martret and Saglio, 1982); the possibility remains that ovulated females merely release increased quantities of conspecific odor and that visual and tactile signals play preeminent roles in spawning. To study the effects of odor alone, this experiment monitored the behavior of solitary males in an open-field maze into which control, food, nonovulated female, and ovulated female odors were introduced. To determine the social relevance of behaviors in the maze, male response to the odors was also observed in an aquarium containing nonovulated mature females with whom the males were familiar.