"The only trials in which the female spent long time periods swimming near the replica was when the mate was yellow," Porfiri said. "In the presence of a yellow male, the females were actively engaged, swimming parallel to the replica and darting back and forth between the mate and the nest," he said, referring to a sheltered section of the tank.
Porfiri and his team noted that, unlike previous studies in which killifish females showed a slight preference for blue or red fins, the yellow pigment used in these trials may be perceived as a "superstimulus," resulting in the females' preference for yellow mates. Other species, notably mosquitofish, have also shown a preference for yellow pigmentation in males, an indication of a higher hierarchic position.
The team plans to deploy a similar robotic platform for future studies of mating behavior in this species, including explorations on how locomotory patterns and visual feedback impact killifish mating preferences.
NYU Polytechnic School of Engineering researchers and their collaborators at University of Illinois at Urbana-Champaign found that fertile killifish females preferred swimming near a male replica that moved through the water via a robotic arm with motions inspired by living killifish.
(Photo Credit: NYU Polytechnic School of Engineering)
While male blue killifish exhibit in red, blue and yellow, fertile females preferred yellow replicas, which mimicked the size, aspect ratio and colors of live fish. A research team led by New York University Polytechnic School of Engineering discovered the surprising affinity for yellow by building a robotic arm that moved the male replicas consistently throughout experiments -- something that scientists cannot do with famously erratic live male killifish.
(Photo Credit: NYU Polytechnic School of Engineering/Giovanni Polverino)
Source: New York University Polytechnic School of Engineering