5 Cool Things About Nematodes

It’s September, and here at ARBICO, it’s Beneficial Nematode season. Every year we put our Beneficial Nematodes on sale at this time to encourage our customers to get them in their garden before winter and get a jump on any soil-dwelling pests looking for a place to overwinter. If you’ve been using them, you know how big a difference they make and if you are not familiar with what they can do, now is the time to try them out. Beneficial Nematodes really should be considered an essential garden tool. To set your thought on these tiny beings, I’ve gathered some interesting tidbits about nematodes in general. 

THEY ARE LITERALLY EVERYWHERE

Antarctic Soil Nematodes

According to a study done in 2019, there are 57 billion nematodes for every human on our planet and they make up four out of every five animals. The type of nematode that we sell here at ARBICO are the type that prey on insects, known as Entomopathogenic Nematodes (EPNs), but they are only one of the many varieties found in the land, water and bodies of living things on earth (for more on this, see my nematode blog from 2019). The air is the only place in our world that they do not inhabit (they have no wings). In the aforementioned article, the researchers discovered that the majority of nematodes actually live in artic and sub-artic environments and not the rainforest, as one might expect (see a fun video here). An oft-repeated anecdote about the ubiquitous nematode says that if you were to remove all but nematodes from the planet, Earth’s topography would still be recognizable in the nematode mass that remains . 

THEY ARE ANCIENT

Nematodes are not just everywhere; they have been here way before us. The oldest nematode discovered thus far is the Palaeonema phyticum and it lived during the Devonian period 419-359 million years ago (many millions of years before vertebrates).This nematode was found trapped in amber inside a land plant, but it had some characteristics of aquatic nematodes. This was the long period when the land, and all its flora and fauna, was developing from the sea, so these characteristics were no doubt a reflection of its evolution from a water nematode to parasite of land animals. As far as humans go, there have been references to nematodes and how they plague people as far back as 1500 BC. 

THEY ARE CLIMATE WARRIORS 

Soil nematodes naturally create healthy soil and are essential to a thriving ecosystem. They aid in maintaining a healthy soil structure by aerating it, play a huge role in decomposition, and are active participants in cycling carbon and nutrients. The artic nematode scientists I mentioned before determined that a large and healthy nematode population is directly related to soil carbon. In other words, the more nematodes there are the more carbon is kept in the soil. There are scientists out there right now hoping to find a way to address climate change by studying how nematodes use carbon and their effect on its emissions.

THEY'VE BEEN KEY IN IMPORTANT SCIENCE

Caenorhabditis elegans 

Nematodes have proven to be a boon for researchers when a multi-cellular subject is needed. They are amazingly similar to human biology in several important ways – they develop from a single cell, have complex development, maintain a nervous system and even seem to have the capacity to learn (more here). It seems safe to say that these characteristics are what drew scientists to the Caenorhabditis elegans nematode when looking for a study subject for DNA research. It ultimately became the first multi-cellular organism to have its DNA fully sequenced. This scientific breakthrough was a world-changing event that has led to a great many scientific and cultural changes. On another note, this particular nematode was on board the Space Shuttle Columbia when it exploded on re-entry on February 1, 2003. All seven astronauts were killed, but their test-subject nematodes survived. For more on how this happened and what scientists were able to learn from it, check out this article. 

THEY CAN BE ZOMBIES

Okay, so not exactly zombies because they don’t eat brains; but they can go into a living-dead state. They do this through a process called cryptobiosis, whereby they are able to suspend all their metabolic activity. Everything just stops. This extreme hibernation is as close to death as something alive can be. Nematodes go into this state when environmental conditions are extreme and unfavorable and will stay in it until conditions improve. This can make it challenging to fight damaging nematodes, but this ability is another source of interest to scientists, especially climate scientists. We all know we are in a time of extreme climate change, so there is hope that we can learn something about how to survive from the humble nematode. There are other creatures who have the ability to hibernate in this way, this short article gives some great examples.

When you add some Beneficial Nematodes to your yard or garden, you are not just helping your plants. You are also taking climate action in some small way by putting nematodes to work doing their thing.

Take Care

Submitted by Pam

Earth's Hidden World Is Not For The Squeamish.

Here at ARBICO we talk about nematodes a lot – specifically our Beneficial Nematodes. These microscopic creatures control a variety of pests in the soil through parasitization. Our customers love them because they are easy to use and highly effective. By the way, they are on sale now through the end of September.

As helpful as the nematodes we carry are, they are by no means the only kind of nematode (aka roundworm) out there and “beneficial” is not a term one would use to describe many of them. Although they are not often seen, nematodes are found literally everywhere on our planet, including intensely inhospitable places like the deepest ocean trenches (they make up 90% of the sea life on the ocean floor) and miles below the Earth’s surface. In fact, the only place they don’t seem to be is flying solo through the air, as they have no wings. Of all the animals on the globe, four out of five are nematodes. They survive and flourish spectacularly and (for the parasitic varieties) have developed fascinating ways to prey on and reproduce within their chosen hosts. While their sheer numbers are staggering, their seemingly endless variations and specializations are downright amazing.

There are 60 species of human parasitic nematodes that cause a very long list of ailments with symptoms that run from the merely uncomfortable to life-changing to fatal. Elephantitis is a particularly gruesome disease that is caused by the bite of a mosquito infected with the parasite. In this way, the nematode has hitched a ride on the insect to get to its ultimate human prey. Gastrointestinal disorders are probably the most common human condition caused by nematodes, some of which may pass through a person without them even noticing. These nematodes travel into the human gut through body openings to get to the nutrient-rich digestive system. This happens just like you think it does.According to the CDC (Centers for Disease Control and Prevention), Hookworms infect 576-740 million people worldwide. These parasites live in the soil and are picked up through the feet. But, how do they do that? According to this article, they locate their prey by smell (insert smelly feet joke here). And then they leap.

The nematodes I’ve been talking about are in the microscopic world, but they can get much, much bigger. Consider, if you will, Placentonema gigantissima. This is the largest known (anywhere from 9-28 feet) roundworm and lives in the placenta of sperm whales. With such an obscure hiding place, it’s no wonder it was not discovered until 1951. Marine nematodes contain not just the largest, but the smallest nematodes as well. We know this because there are scientists who study nematode penis size.

There is no shortage of yucky-yet-cool nematodes. Sphaerularia bombi, a bumblebee parasite is one such creature. Once it has reached maturity inside its host, the female’s uterus will expel from its genital opening and swell into a massive bumpy sack outside the body. This sack, easily twenty times the size of its body, becomes a giant feeding organ gorging itself on nutrients. Learn more here.

Sphaerularia bombi

Another nematode super-specialist is the Panagrellus redivivus. Nathan Cole, known as the father of Nematology in the US, first identified this non-parasitic guy back in the 19th century. This worm is very tolerant of acidity and alkalinity and has claimed some unique spots by feeding on yeast and living in vinegar and even German beer coasters. Although these nematodes are harmless, you may want to ensure that your vinegar is filtered.

Nematodes have been proven to be the culprit in a mystery from the Civil War. After the Battle of Shiloh in 1862, soldiers began noticing a couple of things: there was a greenish-blue glow coming from some of their untreated wounds and those that had the glow healed better than those without. With no knowledge of microbiology, they attributed this glow to a higher power and called the phenomenon “Angel’s Glow”. Fast forward to 2001, when a microbiologist and her son decided to take on the mystery. They figured out that the glow came from a nematode carrying a bioluminescent bacteria that feeds on microorganisms. As this shiny little bacteria fed on its preferred meal, it consumed microorganisms that could cause infection. Here is more on this time traveling detective story.

If the gross factor doesn't bother you, here are some videos showing roundworms in action. This one is a roundworm in a cat's intestine; this one is a large nematode eating a smaller one and this one is a roundworm emerging from a mosquito larvae.


As if it weren’t enough that nematodes dominate our life on earth, scientists are working on taking them to the next planet. It really does make sense, though, since they have so thoroughly saturated every aspect of life on earth. In order to replicate our world elsewhere, it would behoove us to include those roundworms that work for us in insect control and agriculture.

If you are still not convinced that nematodes are everywhere, you should know that they live in Bikini Bottom with Sponge Bob. And apparently have a voracious appetite.

Submitted by Pam