The Amazing Cockroach, Biomimetic Robots and Cyborg Bugs in Recent Years
Although some might squirm at the notion—or the ethics—insects are very mobile and adaptable to all kinds of environments.
Terrestrial insect-machine hybrid robots have long been discussed as alternatives to artificial centimetre-scale mobile robots. These hybrid robots can possess various functionalities (e.g., localization, object detection) by embedding electronic devices while also benefitting from the insects’ robust mobility.
And some bugs, like cockroaches, are extremely good at survival.
For instance, the cockroach has over 1,000 genes that code for chemical receptors that help them navigate the environment, including 154 olfactory receptors—twice as many as the other creepy-crawlies in its insect order—that allow them to pinpoint the burrito bits you dropped. It also has 522 gustatory receptors, with many of them able to detect bitterness, which may help them tolerate potentially toxic foods. The bugs also encode for certain enzymes that can help them resist pesticides and survive extreme environments.
Cockroaches are notoriously difficult to squish to death too. This is because of their exoskeleton which is hard but can flex. It also allows them to move through tiny holes—although most cyborg roaches so far are encumbered by electronic backpacks that I’m guessing are limiting in that regard. The squishabilty inspired some robotic design—in 2016 Kaushik Jayaram at University of California, Berkeley made a biomimetic robot called CRAM:
with a roachlike collapsible exoskeleton and legs with “spines” that work both in the uncompressed and compressed positions. It can squeeze to one-half its height and still move 5 to 10 times faster than soft robots, Jayaram says. “What is exciting is that this gives us an order of magnitude reduction in voids where we can deploy robots,” says Robin Murphy of Texas A&M University, College Station
Previously I wrote “A Brief History of Cyborg Insects (and Spiders)” in mid 2023—a history going all the way back to the 1940s! Some publications have come out since then and there’s one from 2022 I hadn’t seen before…
A Power-Rechargeable Cyborg Cockroach
Published in 2022, researchers at the RIKEN Center for Emergent Matter Science in Japan took a Madagascar hissing cockroach and mounted electronics to control it wirelessly. This is strapped to the insect with a little 3D-printed soft backpack. But unlike before, they also integrated a solar cell so they can recharge the battery powering the electronics. The solar cell is ultrathin and bendable, and glued to the thorax of the cockroach—but where the thorax segments overlap naturally scraped off some of the glue so it alternated between adhesive and nonadhesive.
Non-Invasive Control for Cyborg Insects
The next project came out of Nanyang Technological University, published in 2023; it also involved Hirotaka Sata who was mentioned a few times in my first Cyborg Insect article.
A problem with most cyborg insects is to control them electrodes are implanted. But that permanently damages their bodies and can damage their antennae which of course are critical for natural perception and obstacle-avoidance abilities. By using 3D printing, gold nanofilm and PIL (polymerized ionic liquid) gel the researchers were able to make an electrode that goes around an insect antenna without damaging it. They also made a non-invasive amdomen electrode using silver wire, PIL gel and tape.
Boosting and Breaking Habituation
These last two projects came from the Hirotaka Sato Group, first published online in late 2023.
Using a chemical called methyl salicylate they boosted the locomotion of cockroaches—”enhanced the insect’s walking activity with faster moving speeds, fewer stopping periods, and longer travel distances.”
habituation, the waning of an animal’s behavioral response to a stimulus, as a result of a lack of reinforcement during continual exposure to the stimulus…Vital responses (e.g., flight from a predator) cannot be truly habituated, although a temporary waning of the response may occur.
Because of habituation, the controllability of cyborg insects fades rapidly, just minutes. That’s no good if these are ever to be used in a practical application, like search and rescue. Researchers created an algorithm involving varying voltage levels and a “reactivation function”—a different stimulus signal than normal—to successfully reduce habituation enough so the insect robot could be navigated up to three hours.
