Talk at the First Poecilid Fishes Virtual Forum Samantha M. West (California Polytechnic State University, San Luis Obispo) With Hunter S Wortmann, William Johnson, and Gita R Kolluru
Girardinus metallicus is a Cuban poeciliid with male-specific color polymorphism that extends to behavior. Rare, melanistic (black morph) males display during mating, whereas common plain morph males do not. The role of the display is debated because it is not clearly preferred by females. We tested whether audience identity influences black morph male mating effort, which could also clarify the functional significance of the display. We observed the behavior of focal pairs under the following audience treatments: plain morph male, black morph male, female, empty control. We found audience effects: (1) display duration increased as focal male size increased relative to the audience male, regardless of audience male morph; and (2) males increased mating effort as focal female size increased relative to the audience female. Our results are consistent with the idea that the black morph display has a signaling function to potential rivals as well as to potential mates.
