Scientists demonstrate wall-climbing behavior in cyborg beetles through controlled stimulation, enabling navigation in complex environments.
(Nanowerk Spotlight) In complex, unpredictable environments such as earthquake rubble, collapsed buildings, or narrow industrial ducts, conventional robots often fail to reach where they’re needed most. These settings demand machines that can navigate confined spaces, adapt to unstable terrain, and function without human intervention. Size becomes a critical factor: larger robots can carry advanced sensors and computing hardware but struggle in tight quarters. By contrast, smaller devices can access spaces that are inaccessible to humans or heavy machines—but miniaturization imposes severe design constraints.
Efforts to create small robots that can move autonomously across broken or irregular surfaces have advanced steadily. Yet one persistent challenge remains: enabling these machines to climb. Vertical transitions, such as scaling walls or navigating sudden elevation changes, are particularly demanding. Climbing requires stable adhesion, precise coordination, and energy-efficient actuation—capabilities that are difficult to engineer at small scales. Attempts to mimic the adhesive pads or climbing gaits of insects have yielded partial solutions but often involve mechanical complexity or limited surface compatibility.
This has prompted a shift in strategy. Instead of replicating insect performance synthetically, researchers are increasingly turning to insect-machine hybrids. These biohybrid systems use living insects—whose bodies are already optimized for mobility, sensing, and grip—as platforms for robotic control. By implanting lightweight electronic components and delivering targeted electrical signals, researchers can influence an insect’s movement without overriding its natural locomotion. Cyborg insects, as these systems are known, offer a way to combine the strengths of biology with the precision of programmed control.
The physical constraints of artificial microscale robots—limited joint flexibility, reduced grip strength, and insufficient environmental awareness—make it challenging to climb steep surfaces. Engineers have experimented with adhesion techniques such as suction, electrostatics, and sharp claws, but these approaches often add complexity, increase energy consumption, and struggle on uneven or non-conductive surfaces. Legged micro-robots like RoBeetle or HAMR-E have shown speed and agility on flat terrain, yet they remain unable to perform seamless transitions between surfaces, a task that insects manage instinctively.
Cyborg insects offer an alternative path. These biohybrid systems integrate live insects with electronic control modules, using natural muscle power and embedded sensors as functional components. Their exoskeletons provide mechanical structure, and their neural systems offer coordination unmatched by synthetic equivalents.
Instead of replacing biology with hardware, cyborg systems augment it—embedding stimulation electrodes and lightweight circuitry to direct movement without overriding innate behaviors. Prior research has succeeded in guiding cyborg cockroaches and beetles along programmed paths using electrical cues to the antennae or legs. Yet until now, these efforts were limited to horizontal travel. The ability to command climbing behavior remained an unresolved challenge.
A recent study published in Advanced Science (“Zoborg: On‐Demand Climbing Control for Cyborg Beetles”) reports a method for enabling vertical climbing in electronically guided beetles. The researchers developed a biohybrid platform they call “Zoborg,” built from the darkling beetle Zophobas morio, outfitted with a lightweight electronic backpack and stimulation electrodes. This hardware allows real-time wireless control of the insect’s movement via targeted electrical stimulation of the elytra, the rigid forewings found on beetles.
Overview of Zoborg. A wireless backpack was mounted on a living darkling beetle (Zophobasmorio) with a working electrode implanted into each elytron and one counter electrode implanted into the pronotum of the beetle. Flexible tarsus and sharp claws enable Zoborg to climb over a rough surface like sandstone. Free antennae allow active interaction with the environment for more complex locomotion control. (Image: Reprinted from DOI: 10.1002/advs.202502095, CC BY)
Zoborg’s control module includes a microcontroller and infrared receiver that deliver precisely timed stimulation to either the left or right elytron. This produces a predictable motor response in the beetle: sideways motion away from the stimulated side and an increase in forward movement. By leveraging this response, the researchers created a method for guiding the beetle into a wall and initiating a climbing sequence without interfering with its natural sensory functions.
This approach avoids interfering with the beetle’s antennae, which are vital for environmental sensing. Earlier cyborg systems often relied on stimulating the antennae to direct movement, but this reduced the insect’s ability to detect obstacles and make climbing decisions. By targeting the elytra instead, the new method preserves the natural sensing function while still exerting directional control.
The climbing protocol consists of three coordinated phases. First, the beetle is pushed into the wall through a combination of lateral and forward motion, induced by stimulating one of the elytra. If the beetle does not immediately climb, a second round of stimulation aligns its body parallel to the wall. This posture increases leg contact with the surface and maximizes grip. Finally, repeated stimulation prompts the beetle to begin climbing, using its natural tendency to move toward areas with fewer obstructions—often the open vertical plane of the wall.
Two distinct climbing behaviors were observed. In some trials, the beetle climbed immediately after initial contact with the wall. In others, it walked along the vertical surface until reaching a corner, where spatial constraints made upward movement easier. These behaviors were labeled “middle wall climbing” and “corner wall climbing,” respectively. Both modes used the same stimulation protocol and showed no significant difference in time or effort required. Across all trials, the beetles successfully transitioned from horizontal to vertical surfaces in 71.2 percent of cases.
Performance metrics underscore the protocol’s reliability. On average, beetles completed the climb within five seconds, requiring about ten electrical stimulations. For smaller obstacles such as 5 and 8 millimeter steps—heights close to or below the beetle’s body size—success rates exceeded 92 percent. These trials typically needed fewer than four stimulations and took less than a second to complete. Such consistency highlights the system’s ability to handle not just vertical walls, but also common terrain features found in cluttered environments.
The Zoborg system comprises a wireless controller, electrodes, and a microcontroller-based backpack mounted on the beetle. The electronic module weighs about as much as the beetle itself and is powered either by a tethered external source or a lightweight lithium battery. Importantly, tests confirmed that the beetles could perform climbing tasks outdoors while carrying the full wireless setup. They successfully scaled sandstone walls despite the irregular surface texture, demonstrating real-world applicability.
Control experiments showed that stimulation of either the left or right elytron caused the beetle to move sideways in the opposite direction while accelerating forward slightly. This response pattern was consistent across individuals and trials. Unlike antenna stimulation, which primarily affects turning, elytron stimulation changes velocity in a way that encourages lateral contact with walls—a key requirement for inducing climbing.
The study also examined sensory feedback and behavioral cues. The beetles relied heavily on their antennae and leg sensors to assess wall surfaces. When confronted with short steps that were within antennal reach, they were more likely to attempt a climb. Tall walls, however, triggered avoidance unless the external stimulation protocol was used to push them into engagement. This interaction between innate behavior and artificial control forms the core of the system’s effectiveness.
Navigation in a complex environment. The Zoborg was controlled to cross small obstacles, go up and down inclines, and climb vertical walls, demonstrating the diverse and practical use of elytra stimulation in controlling cyborg beetles over diverse and complex terrain. Green lines indicate stimulation of the left elytron, red lines indicate stimulation of the right elytron, and blue lines indicate periods of both elytra stimulation. (Image: Reprinted from DOI: 10.1002/advs.202502095, CC BY)
While the system is currently manually operated and relies on external command input, the researchers propose integrating onboard sensors for autonomous control. Miniature inertial measurement units (IMUs) could detect changes in orientation and trigger stimulation automatically when a vertical surface is detected. Lightweight cameras may eventually provide visual feedback to support closed-loop navigation. Such additions could further increase the autonomy and responsiveness of cyborg insects in field applications.
The climbing protocol also holds lessons for artificial robotic design. By analyzing how insects adjust posture to minimize energy use—preferring sideways climbing over lifting their body vertically—engineers could implement similar energy-saving strategies in mechanical systems. Simple sensors could help small robots detect wall orientation and align their body accordingly, borrowing from the biological model demonstrated here.
Ultimately, this work advances both our understanding of how insect behavior can be harnessed and our capacity to build agile, terrain-capable machines. By carefully integrating artificial control with biological capability, the researchers have extended the functional reach of cyborg insects. The Zoborg system demonstrates a practical method for navigating complex environments, potentially opening up new uses in search and rescue, environmental sensing, or confined-space inspection where full-sized robots cannot operate.
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