A bioinspired robot has provided the first experimental evidence that live zebrafish can be influenced by engineered robots.
Results published today, 8 June, in IOP Publishing's journal Bioinspiration and Biomimetics, provide a stepping stone on the path to using autonomous robots in an open environment to monitor and control fish behaviour.
In the future, water-based robots could potentially contribute to the protection of endangered animals and the control of pest species.
The robot, created by researchers from Polytechnic Institute of New York University and Instituto Superiore di Sanitá, Italy, was 15 centimetres long and spray-painted with the characteristic blue stripes of the zebrafish. The tail of the robot was mechanically controlled by the researchers to mimic the action of the zebrafish itself.
When placed in a 65 litre fish tank, the movements of the robot's tail attracted both individual and shoals of zebrafish; the researchers believe that such capability was influenced by its bioinspired features which were optimised to increase attraction.
For example, the robot was given a rounder shape to mimic a fertile female, which is preferred by both male and female zebrafish, and its colour pattern – a magnified stripe width and saturated yellow pigment – emphasized distinctive biologically relevant features.
The robot was in a fixed position in the tank so that the tail movements could be controlled, recorded and, most importantly, associated with the behaviour of the zebrafish.
The fish tank where the experiments took place was divided into one large middle section and two smaller sections at either end, separated by transparent Plexiglas. A total of 16 experiments were performed in which individual, and then shoals of, zebrafish were placed in the middle compartment of the tank and two stimuli were placed at either end behind the Plexiglass.
The combinations of stimuli were: one fish versus an empty space; ten fish versus an empty space; ten fish versus one fish; the robot versus an empty space, and the robot versus one fish.
A camera was placed above the tank to monitor the movements of the zebrafish, and statistical tests were performed to calculate whether the robot acted as an attractive, neutral or aversive stimulus and whether this relationship depends on the fish being isolated or in a shoal.
Although the live zebrafish tended to prefer each other to the robot, when given the choice to spend time next to the robotic fish or an empty space, both the individual fish and shoal of fish preferred the robot. While the noise of the robot's motor was shown to decrease its attraction, the actual beating of the tail emphasized its attractiveness.
The corresponding author, Dr Maurizio Porfiri, said: "These findings provide practical evidence that a species' preference for conspecifics may be used to inspire the design of robots which can actively engage their source of inspiration.
"New studies are currently underway in our lab investigating the interactions between fish and robotic fish when they are free to swim together under controlled and ecologically complex conditions."
Notes to Editors
1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Publishing Press Assistant, Michael Bishop:
Tel: 0117 930 1032
Zebrafish response to robotic fish: preference experiments on isolated individuals and small shoals
2. The published version of the paper "Zebrafish response to robotic fish: preference experiments on isolated individuals and small shoals" (Bioinspir. Biomim. 7 036019) will be freely available online from 8 June.
Bioinspiration & Biomimetics
3. Bioinspiration & Biomimetics publishes research which applies principles abstracted from natural systems to engineering and technological design and applications.
4. IOP Publishing provides publications through which leading-edge scientific research is distributed worldwide.
IOP Publishing is part of the Institute of Physics, a leading scientific society promoting physics and bringing physicists together for the benefit of all. Any financial surplus earned by IOP Publishing goes to support science through the activities of the Institute.
Beyond the company's core journals programme, high-value scientific information is made easily accessible through an ever-evolving portfolio of community websites, magazines, conference proceedings and a multitude of electronic services. IOP is focused on making the most of new technologies and continually improving electronic interfaces to make it easier for researchers to find exactly what they need, when they need it, in the format that suits them best. Go to http://publishing.iop.org/.
The Institute of Physics
5. The Institute of Physics is a leading scientific society promoting physics and bringing physicists together for the benefit of all.
It has a worldwide membership of around 40 000 comprising physicists from all sectors, as well as those with an interest in physics. It works to advance physics research, application and education; and engages with policy makers and the public to develop awareness and understanding of physics. Its publishing company, IOP Publishing, is a world leader in professional scientific communications. Go to www.iop.org
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.