The cockroach: nature’s garbage men
Discovering a cockroach infestation is a horrifying experience, and they are difficult to get rid of once established in a residence. Synonymous with filth and unsanitary conditions, some wonder, ‘Why would God create such a disgusting creature?’ Were they really part of God’s original ‘very good’ creation?
In fact, while they get a bad reputation from their pest cousins, there are thousands of species of cockroaches that do not infest homes, and actually play vital ecological roles. They also display indicators of ingenious design that robotics engineers are learning from.
In forests, one of cockroaches’ most important roles is in breaking down leaf litter that accumulates continually on forest floors. Soil microbes actually do most of the work, but cockroaches play a significant part. They break down the leaf litter and move it around, making it more accessible to the microbes. They also carry the microbes around. Their digestive tract and droppings are ideal places for the microbes to live.1
In most ecosystems, lots of insects help decompose plant litter. But in some places, the cockroach is particularly critical. “Many of the ground-dwelling, wingless cockroaches of Australia are important in leaf litter breakdown. This is particularly true in stands of Eucalyptus, where litter production is high relative to forest types, leaves decompose slowly, and more typical decomposers such as earthworms, isopods, and millipedes are uncommon.”2
This decomposing role is important because it makes the nitrogen trapped in the decomposing vegetation available in the soil again, acting as a fertilizer. This role is especially important in desert ecosystems.
The other major function of cockroaches in the ecosystem is as one of the lower rungs on the food chain. They reproduce quickly and are high in protein, making them a good food source for all sorts of insectivorous animals. If the cockroach population were to disappear, most of us wouldn’t miss them, but we might miss the other animals that need them for a food source.
The designed cockroach
The cockroach is very good at getting into tight spaces—a small cockroach can flatten its body to fit through a crack as thin as a dime (1.35 mm). Even a pregnant female roach can fit into a space as large as two stacked nickels (3.9 mm).3 They are also very fast—a cockroach can run 80 cm (30 inches) per second. Their backsides have paired appendages called cerci which detect airflow, and they instinctually run away from any sudden source of wind (for instance, generated by your shoe as you try to stomp on one).4
The cockroach actually is of interest to researchers in robotics because they have several features that would be extremely useful in robots. First, they’re extremely stable. Cockroaches actually do not use their brains to balance—rather, their nervous system controls their legs without the brain by relying on continuous information from the environment. Also, unlike most robots today, cockroaches cope well with losing a leg and can navigate well through obstacles.5
One of the most prominent goals for developing a small maneuverable robot is for finding people trapped in rubble after earthquakes or other natural disasters. But such a robot would have to navigate through dark, uneven spaces. Some robotics researchers are drawing inspiration from cockroach antennae to give robots a way to sense obstacles in their environment.6
The bionic cockroach
The cockroach is also the first living organism to be remotely controlled. For $99, one can purchase a kit consisting of a live cockroach and a tiny computer ‘backpack’. After the cockroach is ‘anesthetized’ by being refrigerated, the cockroach’s antennae and cerci are trimmed, and wires from the ‘backpack’ are inserted. Electrical currents that flow through the wires allow a person to control the live cockroach remotely. Miniature cameras and microphones could also be attached to the ‘backpack’.7
Cockroaches are prime candidates for this sort of process, because they cannot feel pain as humans and ‘higher animals’ can. Indeed, there is evidence that no insect experiences pain like animals do. This is illustrated by the fact that if the cockroach’s head is severed, both parts will continue to live for some time without any indication of suffering. The cockroach’s antennae will continue to move around for several hours—longer if it is refrigerated. The body can live for several weeks until it dies of dehydration.8
Cockroaches did not evolve
Cockroaches first appear in ‘Carboniferous’ layers, supposedly 350 million years ago. But the only difference between cockroaches then and now is that they had external ovipositors. “In other words, they are practically identical.”9 But even today there are small differences between species of cockroaches; some carry their ootheca (egg capsule) internally until the baby cockroaches hatch, while others deposit the ootheca in a safe location. Evolutionists would explain this by saying that the cockroach was so spectacularly adapted to a range of environments that it didn’t need to change. But how did the cockroach get so adapted in the first place? We don’t see developing cockroaches; we see cockroaches that look virtually identical to living cockroaches today all throughout the fossil record. It’s inconceivable that a creature that is supposed to have predated the dinosaurs in the evolutionary timeframe would stay exactly the same while everything else changed around it.
But cockroaches are also cited as evidence of extremely rapid evolution. Pesticides for cockroaches used to be sweet, but cockroach populations developed an aversion to sweet-tasting foods, thus avoiding the poisons.10 This is said to be fast-paced evolution, but is it really? In fact, probably some cockroaches in all populations had this distaste for sugar, so those were the ones that survived the sweet poisons. It only takes a few cockroaches to rebuild a colony of thousands, and all the descendants would then be the sweet-avoiding kind. It’s fast-paced natural selection, but it’s not evolution. It’s not clear that these roaches would even have a survival advantage in places without poison, because their distaste for sweets eliminates some possible food sources.
Cockroaches: ingeniously designed garbage men
While all of us probably have wished that cockroaches would go extinct at some point, they really play an important part in the ecosystem, and scientists are learning a lot of principles of robot design from them. So even the ‘nastier’ parts of the natural world show that God is a good and ingenious designer.
Cockroach facts and myths
MYTH: Cockroaches would survive a nuclear explosion.
FACT: The Mythbusters found that cockroaches would definitely survive more radiation than humans would, but only to a point. Eventually they will succumb like any other living creature.11 Also, Orkin Pest Control notes that even though a cockroach might survive the radiation from a bomb, it would not survive the heat generated by the explosion.12
MYTH: Cockroaches lay their eggs in drinking straws in restaurants
FACT: Cockroach habitats have to have ready access to food and water, so stored drinking straws would not be an ideal home for cockroach hatchlings. Furthermore, cockroach eggs are stored in an egg case called an ootheca, which is “about the size of a dried bean”. The ‘urban legends’ investigation site Snopes helpfully notes, however, that “there’s little reason to suppose that ingesting [roach eggs] would cause harm. While adult roaches are indeed linked with various diseases, their eggs are not and thus should not generally be unsafe to swallow.”13
FACT: Cockroaches will run into a running vacuum cleaner.
Due to a quirk of their physiology, a cockroach will run into a vacuum cleaner hose. It is ‘programmed’ to run away from a source of wind, and its cerci interpret the sucking of a vacuum in front of it as a wind coming from behind it.4
MYTH: Cockroaches only infest dirty houses.
FACT: Actually, any house that can provide them with their needed food, water, and warm, dark places to live is prime real estate for cockroaches. Especially if infested homes are nearby, even the cleanest people can have cockroach problems.14
References and notes
- Bell, W., et al., Cockroaches: Ecology, Behavior, and Natural History, pp. 165–166, Johns Hopkins University Press, Baltimore, 2007. Return to text.
- Ref. 1, p. 167. Return to text.
- Hadley, D., 10 Fascinating facts about cockroaches; thoughtco.com/fascinating-facts-about-cockroaches-1968524. Return to text.
- Hadley, D., How cockroaches detect the flow of air to escape predators; about.com. Return to text.
- Emspak, J., Cockroaches teach robots to balance, 26 February 2013; news.discovery.com. Return to text.
- Lovgren, S., Cockroaches inspire robot antenna design, National Geographic News 8 April 2005; news.nationalgeographic.com. Return to text.
- Oremus, W., Here come the remote-control cyborg cockroaches to save the day, 7 September 2012; slate.com. Return to text.
- Choi, C., Fact or fiction?: a cockroach can live without its head, 15 March 2007; scientificamerican.com. Return to text.
- Evolution of cockroaches, cureallpest.com.au/evolution-of-cockroaches, accessed 2014, available at web.archive.org. Return to text.
- Hecht, J., Roaches have evolved to evade toxic traps, New Scientist, 24 May 2013; newscientist.com. Return to text.
- Mythbusters database, Cockroaches survive nuclear explosion; discovery.com. Return to text.
- OrkinVideo, Could a cockroach survive a nuclear bomb? 17 June 2014; youtube.com. Return to text.
- Mikkelson, B., Straw bedded, 22 March 2010; snopes.com. Return to text.
- Simental, A., NMSU professor answers 10 myths about cockroaches, Myth 4, 18 February 2014; newscenter.nmsu.edu. Return to text.