Fitting solar panels to an insect is not an easy task, and scientists first scanned the cockroaches before 3D printing the electronic devices using a special bendy material that fit snugly around the thorax, allowing the creature to still move easily.
Early attempts where the solar cells were too thick, or too rigidly attached, saw the cockroaches having difficulty righting themselves when on their backs, and running far more slowly.
Many labs are trying to mimic swarms by creating miniature robots, but the Riken team believes it is simpler to use actual animals, and hope to move to flying insects in the future.
They said it was important to use flexible electronics to allow the insects to move easily.
Dr Kenjiro Fukuda, lead scientist, said: “Considering the deformation of the thorax and abdomen during basic locomotion, a hybrid electronic system of rigid and flexible elements in the thorax and ultrasoft devices in the abdomen appears to be an effective design for cyborg cockroaches.
“Moreover, since abdominal deformation is not unique to cockroaches, our strategy can be adapted to other insects like beetles, or perhaps even flying insects like cicadas in the future.”
Commenting on why cockroaches were chosen, Dr Fukuda added: “First, they are one of the biggest roaches in the world, the body length reaches 5-7 cm.
“The size is very important to generate larger power using solar cells because area determines the power output. Second, they have a long lifespan of up to 5 years and are relatively resistant to the environment.
“Third, they do not fly, which makes it easy to control their motion using stimulation wires.”
The research was published in the journal Flexible Electronics.