"We designed a wireless controller that is only 10 mm wide, 10 mm long and 3 mm high – small enough to be implanted entirely into the cockroach's abdomen," explains Professor Sato. The board weighs just 0.5 g and runs on a 9‑mAh lithium‑polymer battery, also implanted. It uses sub‑1 GHz communication and outputs biphasic electrical pulses to stimulate the insect's antennae (for turning) and cerci (for forward walking). A silicone elastomer coating insulates the electronics, making them biocompatible.
The team built a track with a movable shutter that created an 8‑mm vertical gap – smaller than the cockroach's body height. Intact cockroaches naturally lowered their heads, lifted the shutter and pushed through, succeeding 95% of the time. When the same insects carried the controller as a backpack (glued to the thorax), the backpack hit the shutter, forcing the animal to lift it much higher; success rate plunged to 15%, and traversal time more than doubled. In striking contrast, cockroaches with the fully implanted controller performed almost identically to intact ones: 90% success and traversal times even slightly faster (8.1 s versus 9.6 s). "The implant does not alter the body's roundness or the natural tripod gait," says Professor Sato. "The insect keeps its streamlined shape, which is known to reduce mechanical resistance and assist body rotation when squeezing through gaps."
To demonstrate controllability, the team implemented an automatic navigation algorithm. When the cyborg's forward speed dropped below 5 mm/s, it received a forward stimulus to the cerci; if its heading deviated more than 45° from the target, it received antenna stimulation to turn back. Over 66 trials, 90.9% reached the virtual target successfully. The mean turning response was 16.7°/s for left stimuli and 26.3°/s for right stimuli, and forward stimulation reliably re‑started walking.
The real advantage of implantation was then tested in a three‑stage obstructed corridor: stacked bricks, randomly arranged cables and a narrow slit. Cyborgs with the backpack succeeded only 40% (bricks), 50% (cables) and 0% (slit). Those with the implant succeeded 95%, 89% and 63%, respectively, and traversed each obstacle significantly faster. "The backpack often got snagged on bricks or cables, forcing the insect to reroute or give up," notes Professor Sato. "The implant allows the cockroach to use its full behavioral repertoire – rolling, side‑stepping, pushing – just like a normal insect."
To make the procedure more reliable, the team also developed a robotic arm‑based implantation system. A parallel gripper with a custom fingertip pierces the intersegmental membrane and pushes the controller inside; the whole process takes 25 s and achieves 100% success in medium‑sized cockroaches. In addition, the researchers discovered that stimulating both antennae simultaneously for 1.2 s reliably induces backward walking – a useful escape maneuver when the insect meets a dead end.
Survivorship after implantation improved from 43% at 7 days to 86% after refining the surgical technique (using a spatula to detach internal tissues before insertion). With a practical operational window of several days, cyborg cockroaches are already suitable for missions such as post‑disaster structural inspection or pipeline monitoring. Future work will focus on even smaller flexible electronics, biofuel cells or solar films to reduce invasiveness further, and integration of sensors (IR, camera, IMU) for autonomous task execution.
"Our study shows that how you attach the electronics is not a minor detail – it directly determines whether the cyborg can actually navigate the terrain it was meant to explore," concludes Professor Sato. "Full implantation preserves the insect's evolved body intelligence, making cyborg insects truly capable of operating in the cluttered, unpredictable environments where they are most needed."
Authors of the paper include Kazuki Kai, Le Duc Long, Qifeng Lin, and Hirotaka Sato.
This work was supported by the Japan Science and Technology Agency (Moonshot R&D Program, grant numbers JPMJMS223A and JPMJMS2238) and the Singapore Ministry of Education (RG82/24).
The paper "Fully Implanted Miniature Radio Controller Boosts Cyborg Insect Mobility in Challenging Terrains" was published in the journal Cyborg and Bionic Systems on May. 25, 2026, at DOI: 10.34133/cbsystems.0589.
