Why Do Termites Eat Wood? Facts And Figures

We often tend to anthropomorphize non-humans, including insects. When we hear about strange habits or behavior, an inadvertent shudder may well be our first response.

The thought of termites surviving by eating wood could definitely fall under that category.

So, why do termites enjoy eating wood, exactly?

First, let’s bust a mini-myth. While termites are famously known for eating wood, they do not do so nearly as fast or as omnivorously as they are depicted in popular cartoons, where they can be seen munching in a circle on every inch of wood in eyesight.

In reality, termites do enjoy wood as a meal. However, they also have definite preferences. In particular, not all wood has the nutrients the termite needs to survive.

Other woods may be less attractive since they are harder to bite through.

So while termites can bite through a variety of woods and materials, they may be selective with what they “eat” – as in ingest and digest.

To Eat or Not to Eat      

To eat is to consume, put in the mouth, chew, and swallow for sustenance, or energy. What is important to note in this regard is that eating not only represents the action of putting in the mouth.

It does not even end with chewing or swallowing. To complete the conventional definition of eating, the initial actions must be followed by both ingestion and (subsequently) digestion, which in turn provides the eater with sustenance, releasing energy within their body.

As a quick example, if someone is sitting in a meadow and absentmindedly chewing on a blade of grass while enjoying the sunshine, that is not eating.

Similarly, if someone accidentally swallows a harmful substance like bleach, that is not eating either and will likely be followed by vomiting or other painful experiences.

Therefore, if a termite eats wood, they must receive sustenance out of it.

What Nutrient does a Termite Need?

The main nutrient the termite needs is cellulose, which is a polysaccharide of glucose units which make up most of the cell walls in plants.

Cellulose is a natural polymer, that is to say, a long chain of the same molecules stuck together. The main ingredients are carbon, oxygen and hydrogen atoms.

Human beings are not able to digest cellulose. However, its a fiber that helps in our overall digestive process and overall gut health by helping food to move through our gut. It also helps push waste out of the body.

This fibrous substance is found in most anything vegetative such as grass, wood, cotton, leaves, as also in the excrement of herbivorous animals.

That is why a person chewing on grass is not eating – we can’t get nutrients out of the cellulose in the grass. Cows, sheep, and horses, on the other hand, can digest cellulose, which is why they can survive on grass.

Cellulose is also found in many other everyday items, including cotton clothing and paper. Nearly 90% of cotton fibers are cellulose.

Paper in its purest form is almost entirely cellulose fibers, though when mixed in with other chemicals it can get diluted down to about 90%.

How are Termites Able to Digest Wood?

Cellulose seems like a rather hard diet to digest. As noted above, there are very few creatures with the ability to process this fiber and get nutrients out of them.

Termites happen to be one of them. Even so, termites are not able to digest the wood on their own. They can only do so with help from their friends – bacterial protozoa that live in their stomachs.

These are microorganisms that live in the termites’ digestive system, providing enzymes to break down the wood.

The protozoa turn the wood into simple sugars that the termite is then able to digest. To begin with, both the termite and the protozoa digest these sugars.

This stimulates the protozoa to release acids which then helps the termite to metabolize or process the food.

The termites and their intestinal protozoa represent a symbiotic host-parasite relationship. The termite and their bacterial protozoa need each other to survive.

Specific Research Findings in this Regard

There have been detailed studies on this topic, for example, the University of Chicago study.[1] Their findings go beyond examining the role of the protozoa in the life and nutrition cycle of the termite.

Here are some of the most interesting findings from such studies:

• The termites are not born with protozoa. They receive protozoa after the termite larvae are born, which they get by consuming the feces of the adults.
• Protozoa are present in enormous quantities within the intestines of three out of four known families of termites, along with all their species and genera – they are Kalotermitidiae, Rhinotermitidae, and Mastotermitidae. These are the families that can digest raw cellulose. The fourth family, Termitidae, does not possess the protozoa and does not derive nutrients from wood.
• The researchers incubated the wood-eating termites at a temperature of 36°C for 24 hours to experiment. Under those conditions, the protozoa perish but the termite itself remains unharmed. At this point, the defaunated (as in, with the protozoan fauna killed off) are found to demonstrate markedly different behavior:
  • If fed wood, the termites without bacterial protozoa will perish within 10-20 days, whereas
  • They will survive indefinitely if they are fed humus, which is the digested form of wood or fungus digested cellulose.

The bottom line, a majority of the families of termites gain intestinal protozoa from their elders, which then allows them to digest wood and gain nutrients from it.

Not all wood is created equal, though.

So, What Types of Woods do Termites Prefer to Eat?

Staying within the families that do digest cellulose, the answer may be different from species to species. Given that there are 2,000 known different types of termites, the menu is different for each.

While they all feed on objects containing cellulose, how they prefer to get at the cellulose varies from species to species.

Drywood Termites

For instance, take drywood termites (Cryptotermes brevis, family Kalotermitidae), commonly known as the West Indian drywood termite or the powderpost termite.

In general, they prefer untreated wood. They will feed on the structural wood of the home, the framework, and furniture.

Some drywood termites may even give the hardwood floor a try; but if the floor is treated, the termites have an unlikely chance of surviving after ingesting the chemicals.

Dampwood Termites

A different example is dampwood or rottenwood termites (Zootermopsis angusticollis, family Archotermopsidae). They are an interesting group to start with since most species under their original family Termopsidae – belonging to the order Blattodea – is now largely extinct.

The remaining members, including the dampwood termites, have been organized under the family Archotermopsidae. They live above ground and are bigger than subterranean termites.

You will rarely find these termites in the home unless the wood is damp, dead, and decaying. However, if they arrive, beware.

Dampwood termites start with wood that is closest to the ground – they love mulch and a host of other wet woods, which are most likely to be found in the foundations of the home sticking above the ground level.

During an infestation, dampwood termites will be eating into the wooden structures around your home from the ground level up.

Subterranean Termites – How Do They Find Wood from Underground?

The most damage causing termite is known as the Subterranean termite – which are members of the family Rhinotermitidae.

The family consists of nearly 350 recognized species, including well known ones such as the Formosan termite (Coptotermes formosanus), the Asian subterranean termite(Coptotermes gestroi), and the Eastern subterranean termite(Reticulitermes flavipes).

One and all, they can cause havoc in and around a home.

These guys live underground searching for their meals through the soil, which is exactly how they find the uncovered wooden support beams under the home.

As they move up into the home for more, they build tunnels for protection made of their saliva and mud, so they do not get dehydrated as they’re getting food above the ground.

Detecting such holes is a prime indicator of an infestation.

A Termite’s Bite, and Menu Preferences

Termites have a rather powerful chomp. The peak bite force of a termite has been estimated to exceed 150 mN (meganewtons).

That is really strong, equivalent to a force in excess of 150 million newtons. By contrast, human bites range between 1,100 and 1,300 newtons. Using simple extrapolation, a termite bite can pack 125,000 times the power of a human bite!

In addition to the peak biting force, consider two other factors:

• Termites are tiny, making their bite strength is all the more impressive
• Termites are also among the fastest biters on the planet. A high speed camera study of the Panamanian termite revealed the fastest “mandible strike” recorded.[2]

The reason for the strength and quickness is simple – termites have to stave off enemies in extremely cramped conditions, often underground.

They have to strike with effectively massive, deadly force. They employ the same tactic that locusts and trap-jaw ants do – deforming their jaws to store up energy prior to chomping down – to gain maximum advantage.

If they’re able to chomp through different varieties of mostly raw and damp wood rich in cellulose, what else can termites bite through?

As we just demonstrated, termites have an impressive bite and can cause damage to more than just the wood in the home.

Back to Menu Options

The woods the termite prefers are any type of untreated softwood, as this is easier to break down to eat and digest. Termites will also go for untreated hardwoods; it just takes them more effort.

Gumtrees are a natural habitat for termites and can be found in Central America, South America, Australia, India, and Tasmania, to name a few.

Termites will also eat smooth and dry woods within your homes, such as floorboards, the wood within the furniture, baseboards, and any softer untreated wood. Even particle boards are good fodder.

All of these contain their favorite nutrient – cellulose. However, if any of these materials have chemicals on them, the termite will usually avoid it altogether and not bite through it.

Depending on the type of termite, they will also have no shame in eating books, cotton clothing, and cardboard.

This makes sense since these materials can be overwhelmingly made of cellulose, as we had discussed earlier. So, any untreated paper materials could be the termites’ next menu preference.

So, will termites eat all wood in sight?

Woods Termites will Typically Refuse to Eat

We had discussed that chemically coated woods are harmful to termites, and they will tend to avoid it.

Additionally, and due to similar reasons, certain types of naturally occurring woods will deter termites, at least temporarily and sometimes forever.

Examples of termite-resistant wood include redwood and cedar. Both these woods have allelochemicals that are toxic to termites.

However, the wood on these trees is still organic. It will eventually break down which then stops the process of generating the allelochemicals, allowing the termites to safely eat the wood.

Therefore, while they are short-term deterrents, redwood and cedar are not reliable materials if you are looking to permanently deter termites.

Another natural wood that may temporarily deter some species of termites is bamboo. This is a hardwood, more difficult to bite through, and termites would rather look for something easier to chomp on.

However, bamboo is ultimately grass and rich in cellulose, so for a hungry termite, hardness will not prove much of a deterrent.

Termites will leave treated wood alone, such as pressure-treated wood. Treated wood is infused with chemicals to prevent rotting, fungi, and termite prevention.

Termites can detect the chemicals and will naturally look for something else.

We will discuss methods to effectively deter termites from eating wood, especially within your home, in a subsequent article.

The Final Word

Termites do massive amounts of damage to human property. In the US alone, they affect upwards of 600,000 homes every year and cause over $5 million in property damage.

Their eating habits have therefore been the subject of intense study by various scientists and pest control experts.

Luckily, there are both commonsensical and more aggressive methods to deter termites from eating wood. We will discuss that in a separate post.

Alright, that’s it for this article, here are a few hand-selected articles that you might also find interesting reads:

Are termites attracted to light? Absolutely, but only a certain group of them.

Are termites hard to get rid of? Yes! But These Tips Can Help

Best non toxic way to control termites

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[1] https://www.journals.uchicago.edu/doi/pdf/10.2307/1536724

[2] https://www.livescience.com/3152-termite-bite-fastest-world.html