A group of researchers carried out a very particular experiment on a cockroach in a study published in Nature Communications. The research team of Fan and Sato, from Nanyang Technological University of Singapore have built and made the cockroach “wear” a small one “mutt” which allows him to breathe even underwater, transforming him into what the authors define as a amphibian cyborg insect. This way the insect can stay in the water even for three hours without any problem, cross flooded tunnels and squeeze through cracks just two centimeters high. The goal, however, is not to create an aquatic cockroach. The idea is much more practical and is to make these small systems capable of also explore flooded environments. If the technology continues to develop, it could one day be employed during rescue operations after an earthquakea flood or the collapse of a building, entering too narrow spaces or too risky for rescuers and even for many robots designed for this type of intervention.
Why use a cockroach at all: resistant animals
If the goal is to enter the rubble or squeeze into a crack a few centimeters wide, it would be natural to think of a small robot. The problem is that, when robots become very small, the technical difficulties also increase. Batteries, motors and circuits take up space and, by reducing the size, the autonomy is inevitably also reduced. For this reason some researchers have chosen a different path. Instead of building a robot from scratch, they exploit an animal which already has everything it needs to move: the cockroach walks thanks to its muscles and obtains energy from metabolism. Added electronics don’t move it forward, but they only serve to guide its movements. In this way the energy consumption of the “robotic” system remains extremely low. Then there is another advantage: Cockroaches are extremely resistant animalsthey can squeeze into very narrow openings and move easily through debris, pipes and other complex environments where many small robots would have difficulty proceeding. In this study, lo was used in particular Madagascar hissing cockroach (Gromphadorhina portentosa), which is large and strong enough to support the weight of the intended device.
The water problem solved with a small underwater “wetsuit”.
To make the system work, however, the problem of breathing. A cockroach, in fact, it is unable to survive underwater for long. It does not have lungs, but breathes through small holes distributed along the thorax and abdomen, called spiracles, from where oxygen is transported into the body by a network of tiny channels, the tracheas. When these holes are covered by water, the airflow is interrupted and the animal quickly suffers from asphyxiation.
To make it operational even under water, the researchers therefore had to design a real one Miniature “diving suit”.. The device is made up of three main elements:
- flexible waterproof shell that envelops the abdomen of the cockroach preventing water from entering.
- a small one oxygen generator.
- very thin tubes which transport oxygen directly to the insect’s spiracles.
Credit: Fan, et al. Nat comm (2026)
To check how long the air reserve lasted the researchers monitored the oxygen present inside the suit during the experiments. One milliliter of hydrogen peroxide was enough to produce approximately 6.2 milliliters of oxygen. In the first few minutes the level rose rapidly, reaching an average concentration of 47.4% after approximately eight minutes. Then he started to decrease slowly.
Even after three hours, however, it was still equal to 14.8%, a quantity which, according to the authors, allows the cockroach to continue breathing without difficulty. When this value drops below 5%, insect activity drops dramatically and the risk of death increases. The authors also checked that the device had no negative effects on animals. Five cockroaches were observed for three days after the experiments, all of them are survivors and continued to behave normally. The generator temperature also remained stable, oscillating between 23.6 and 24 °C, without producing enough heat to disturb the insect.
Crossing spaces where nothing else can pass
Subsequently the researchers also changed the system eliminating the external backpack containing the electronics and placing these components insideinside of the cockroach body. In this way the insect managed to pass through a submerged crack just 2 centimeters higha size that represents an obstacle both for insects with external backpacks and for many small amphibious robots. Furthermore this configuration makes the system more stable and reduces the risk of some component getting stuck during exploration.
An immersion time of up to 2-3 hours
The most evident result concerns precisely the dive time. A normal cockroach, completely submerged, stops moving within about two minutes. With the diving suit, instead, the insects remained active and continued to respond to commands for two or three hours. Movement speed also remained quite high. On the ground the cockroach advanced on average at 87.5 millimeters per second, underwater the speed decreased slightly to 78.4 millimeters per seconda reduction of approximately 10%, mainly due to the greater resistance exerted by the water. As the hours passed, performance gradually decreased due to the effect of fatiguebut after three hours the insect still continued to move.
The test in the most difficult conditions
To test whether the system could be useful in situations similar to a real disaster, the researchers built a long tunnel 1.7 meters with two consecutive hurdles. There first section it was filled with carbon dioxide. This gas, at high concentrations, can quickly cause a state of immobility in insects. Instead, the second sectionwas completely submerged in water. The non-shedding cockroaches almost immediately stopped responding to stimuli in the carbon dioxide-rich zone or suffered asphyxiation within 45 seconds of being submerged. The animals were then recovered and they made a full recovery after being returned to the air. Those equipped with wetsuits, however, crossed both areas without problems while maintaining a normal ability to move. In all three tests carried out they managed to complete the route successfully!
