Courtship Role Reversal in Sevenspine Goby, Gymnogobius heptacanthus (Gobiidae)

Abstract

Females of the sevenspine goby Gymnogobius heptacanthus are more colorful and active in courtship display than males. Females tend to exhibit agonistic behavior in female-female competition reaching its highest level in their completed readiness to spawn. In addition, females are sex-role reversed, performing courtship displays. Fish behavioral patterns are rather simple. Thus, the level of male aggression is very low. They do not initiate any courtship display. The spawning ground is not a strictly-guarded site of importance. A small number of male spawners can be a key factor for the sex-role reversal occurrence.