University of Western Australia
Research into how a small mangrove-dwelling crab spots and avoids predators could have applications in robot development, according to a study from The University of Western Australia.
Dr Callum Donohue, from UWA’s School of Biological Sciences, looked at the fiddler crabs’ reaction to perceived threats in research that involved recording the arthropods’ behaviour on treadmills.
“We placed the animals on a rotating Styrofoam ball, floating on an air cushion, surrounded by four computer monitors,” Dr Donohue said.
“We then exposed the crabs to a range of virtual stimuli of different sizes and speeds to mimic approaching predators. The results showed that the crabs time their escape responses according to the speed at which the image of the predator grows on the crabs’ retina.”
Dr Donohue said in the wild, using the speed at which the predator’s image grows, allowed the small crabs to respond early and differently to flying and running bird predators.
“The crabs are the only arthropods we know of that use a speed-based decision criterion to time escape behaviours,” he said.
The research, Fiddler crabs are unique in timing their escape responses based on speed-dependent visual cues, was published in Current Biology.
Associate Professor Jan Hemmi, from the UWA Oceans Institute and head of the Neuroecology Group at UWA’s School of Biological Sciences, said understanding how animals with small eyes and brains made complex decisions provided insight for robot development.
“As technology gets more complex, finding ways to simplify decision routines is becoming more important than ever before,” Associate Professor Hemmi said.
“There is still a lot we can learn from studying the solutions the small creatures of the natural world have evolved to use so that they stay safe.”