Buzz
Whether you love them or despise them, worms are everywhere. Delicate and soft, these creatures find refuge in their oddities. Some form unsettling alliances, while others regenerate entire brains.
Worms can feed without mouths, dominate other species, and thrive in extreme conditions where most life forms would perish. These slithering marvels have captured the fascination of scientists. Not only could they help fertilize planets, but one species may even offer a solution to the global plastic pollution problem.
10. Earthworms on Mars
While there are no earthworms currently exploring the Red Planet, a 2017 study revealed that they could potentially survive in Martian soil. Dutch earthworms were placed in a special mix, using a synthetic Martian sand developed by NASA years ago. This sand closely mimics the real Martian surface, aiding in research for rovers, spacesuits, and mining gear.
To test if earthworms could survive and contribute to Mars' fertility, scientists mixed the simulated soil with manure fertilizer and rucola plants. The main concern was whether the grains would be too sharp for the worms, as Martian sand, being less weathered than Earth's, is coarser.
For comparison, Earth’s silver sand, composed of quartz, is often used in gardening. The pig manure was meant to counteract the grain issue. Surprisingly, along with the earthworms, it transformed the fake soil into a better growing medium than silver sand. The most exciting discovery came when scientists realized the worms had unexpectedly begun to reproduce.
9. Zombie Worms with Acid
In 2002, strange worms were discovered off the coast of California. Dubbed “zombie worms,” they have an unusual appetite for consuming the bones of large marine animals. They burrow into skeletons until they resemble Swiss cheese.
While bone-crushing worms might seem familiar, this species is unique in that it lacks any mouthparts to chew. In fact, it has no digestive system. If zombie worms can't gnaw or digest bones, how do they create holes in the skeletons?
In 2013, the mystery was solved. It turned out the creatures were indeed to blame. Rather than using teeth, they dissolved bones with acid. This toxic substance is secreted by their skin, which produces it via proton pumps similar to those in human kidneys.
Remarkably, the process behind acid production is strikingly similar to how osteoclasts in humans break down bone matter. (Osteoclasts are cells responsible for bone resorption.) However, how the worms process the dissolved remains remains a mystery.
8. They Hijack Brains
Sometimes, ants stumble upon a tempting glob of goo. Hidden within this treat is the larvae of the lancet liver fluke. Once ingested, the larvae transform into a worm that takes control of the ant’s brain.
The worm then manipulates the ant, driving it up a blade of grass where a grazing animal is likely to swallow it. After a cow eats the ant, the worm lays eggs. These eggs are expelled by the cow, only to be consumed by snails. Inside the snails, the larvae hatch before being excreted as tasty orbs for ants.
Although scientists understood the lifecycle of the flatworm, the mechanism behind how it controlled the ant’s actions remained a mystery.
In 2018, researchers took a bold step and decapitated infected ants. Using a miniature CT scan, they captured the first-ever images of the brain takeover. These scans revealed that multiple flatworms often vied for control of the same ant brain.
The dominant fluke used its mouth suckers to grip the neural areas responsible for controlling the ant’s movement and jaw actions. This could explain why a zombified ant climbs a blade of grass and locks its jaws at the top, effectively anchoring itself in place for an unsuspecting grazing cow.
7. Cryogenic Superstars
Nematodes are microscopic worms that typically squirm unnoticed in the soil.
In 2018, they shocked the world. Well, maybe not everyone, but nematodes from Siberia demonstrated that cryogenics—the practice of freezing organisms for future revival—might not be as far-fetched as some think. This technique could even allow people to be revived hundreds of years after being frozen.
In 2018, researchers discovered nematodes in permafrost from the Pleistocene epoch. The worms had been frozen for 42,000 years. When thawed, two species began to move, and not only did they stir physically, but they also consumed their first meal in millennia.
This event marked the first-ever “ice rebirth” of a multicellular organism. Since it happened naturally, scientists are still trying to figure out how the nematodes managed to survive 42,000 years frozen solid.
6. They Form Deadly Partnerships
When Heterorhabditis nematodes team up with the bacteria Photorhabdus luminescens, no insect is safe. If a grasshopper happens by, the nematode launches itself from the soil and burrows into the host’s body.
Once the worm enters its victim, it vomits bacteria from its gut. These toxic bacteria swiftly kill the insect and release a chemical that prevents the body from decaying. This ensures that the worms have weeks of fresh meat and a perfect nursery for their baby nematodes.
To keep larger predators, like birds, from snacking on the deceased insect, the bacteria employ a few clever tricks. They turn the carcass red, using one of nature’s most recognizable warning colors. Additionally, the body emits a scent of almonds, another signal that birds understand as a danger. Strangely, the body also glows a neon blue.
The nematodes essentially serve as transport for the bacteria. Just before the worms leave the insect, the baby nematodes consume some of the bacteria, which they later regurgitate into a new host.
5. Considerate Cannibal Parents
To the naked eye, nematodes seem identical. These microscopic creatures are all smaller than sesame seeds and lack distinguishing characteristics. Despite this, nematodes can recognize their own offspring.
This first became clear when researchers observed the creatures' feeding behaviors. In a gruesome twist, some nematodes ate each other. However, despite their cannibalistic tendencies, they refrained from devouring their own offspring. When presented with unrelated nematodes, they eagerly consumed them.
This puzzling behavior went unexplained until 2019, when scientists turned to a nematode called Pristionchus pacificus. This species had a disturbing habit of preying on both other nematodes and its own kind.
DNA analysis uncovered a gene named SELF-1. This gene was found to be responsible for why the young nematodes were spared by their killer parents. How did the researchers confirm this? When they removed SELF-1, the worms began eating their offspring with abandon.
4. The Buttless Wonder
For many years, scientists were puzzled by how Paracatenula managed to survive. This flatworm, lacking a mouth, gut, or rear end, thrives in the seabeds of regions with mild temperatures. Most species depend on these features to eat, digest food, and excrete waste.
The answer came recently with the discovery of a fascinating symbiotic relationship with a bacterium called Riegeria. Together, they engage in a chemosynthesis process, where energy is derived from a chemical reaction rather than from sunlight.
The bacteria generate enough nutrients to sustain the worm. Paracatenula doesn't require a mouth to absorb this 'food' because the bacteria already reside within the worm. In return, the organisms benefit from the worm's waste, making a digestive system unnecessary.
What makes this partnership particularly remarkable to scientists is that, in typical chemosynthetic relationships, worms need to consume the bacteria to gain the benefits. The symbiotic relationship between Paracatenula and Riegeria is extraordinary, having lasted for 500 million years.
3. The Plastic Solution
In 2017, a scientist who also kept bees noticed parasites in her hives. She decided to temporarily place the waxworms in a shopping bag. After taking care of her beekeeping tasks, she found that the plastic bag had numerous holes, likely caused by the worms chewing through the plastic or even eating it.
If the worms had actually consumed the bag, these parasites could become a solution to one of the most pressing pollution issues of our time. A surprising experiment showed that the worms were capable of dissolving plastic.
To investigate, researchers squashed a few of the worms and spread their gooey remains over plastic shopping bags. The bags shriveled and vanished, which was an exciting discovery given the challenge of breaking down plastic.
In a follow-up test, 100 waxworms ingested 92 mg of polyethylene in just 12 hours—1,400 times faster than any bacteria used in previous trials. Scientists believe the worms possess an enzyme that breaks down beeswax, and it’s possible that this same enzyme is responsible for dissolving the plastic. If researchers can replicate this enzyme, it could offer a solution for mass plastic destruction.
2. They Regrow Brains
Between 2012 and 2014, ribbon worms were collected from various locations, including Argentina, the United States, New Zealand, and Spain. These 22 species were placed in research containers and sent to the lab for testing their regeneration capabilities.
Surprisingly, after several of these worms had their heads severed, eight species grew new heads. In one remarkable case, an individual managed to regenerate even after losing the entire front half of its body.
In 2019, a deeper investigation overturned a long-standing scientific assumption. It was previously believed that regeneration in related species originated from a shared ancestor. However, the ribbon worm’s regenerative abilities defied this theory.
Tests revealed that their shared ancestor was not known for head regeneration. From an evolutionary perspective, the eight species achieved a remarkable feat—they each independently evolved the ability to regrow heads without relying on a common ancestor.
1. They Thrive In Poison
In 2008, scientists ventured into Sulphur Cave in Colorado. The cave, filled with enough hydrogen sulfide to be fatal to humans, required the researchers to wear special breathing equipment, while a medical team stood by outside. In addition to the lethal gas, the cave also contained sulfuric acid that could burn through clothing.
To their astonishment, a new species of worm was discovered in this hazardous environment. The finding of Limnodrilus sulphurensis in Sulphur Cave marked these creatures as extremophiles—organisms that thrive in conditions where most other lifeforms, including humans, would perish.
The worms' striking bloodred color also intrigued researchers. Their hemoglobin has a much higher affinity for oxygen compared to other species, helping them survive in the cave's oxygen-deprived atmosphere and possibly contributing to their vivid scarlet appearance.
Other bright red worms are found near hydrogen sulfide vents deep beneath the sea. These marine worms rely on bacteria to process the toxic substance, whereas the Sulphur Cave worms seem to handle the toxin all on their own.
