Beneficial termites? How scientists grew to love a household pest

Termites are a lot of things, but most people wouldn’t call them “cute.” Gregg Henderson isn’t most people.

He’s an entomologist, and has studied the social behavior of termites at Louisiana State University for nearly 30 years. Professor Henderson’s affection extends to the termites in his house – the ones he keeps in buckets, that is. But at the university, his job is to conduct research that will help make better baits, insecticides, and other pest control methods.

That dissonance matches most of humanity’s relationship to termites. They’re seen almost solely as small vermin that can literally eat people out of house and home. But characteristics that make the bugs such good habitat destroyers also make them vital players in many ecosystems. In fact, some ecosystems might collapse without them.

Most people don’t care to learn more about the insects beyond how best to kill them.

Even scientists have been slow to catch on. Termite research long focused on how best to eradicate the bugs. But slowly, that has been changing. Discoveries made by a handful of fascinated scientists have inspired more interest.

And the more scientists learn, the more complicated humanity’s relationship with termites can become.

“You have to ask yourself a philosophical question,” says another termite researcher, J. Scott Turner. “Is the termite a pest, or is the termite just being a termite?”

Ecosystem protectors

The latest chapter in the developing story of termite fascination comes out of the Bornean rainforest, where termites helped the ecosystem weather an extreme drought. The discovery, which was accidental, is detailed in a paper published Thursday in the journal Science.

Researchers wanted to better understand the role termites play in that ecosystem generally. They had set up an experiment that suppressed a termite colony to see what would happen in their absence, with control plots for comparison.

Then, an El Niño drought hit in 2015. So they ran the experiment a second time, during a more typical year.

As it turned out, in the control plots, termite activity during the drought was twice what it was under normal conditions. And, as a result, there was more moisture in the soil, a greater variety of nutrients, and seedlings survived at a higher rate.

“We got quite lucky,” says study co-lead author Louise Ashton, an assistant professor at the University of Hong Kong. “It wasn’t until the system was under that stress from the drought that the roles of termites in buffering the effects of drought really became apparent.”

This isn’t the first time termites have been found to bring resiliency to an ecosystem. The critters are actually credited with making some of the dry regions in Africa lush.

“Southern Africa’s arid savanna, for example, is really largely constructed by what termites enable other things to do,” says Professor Turner, a physiologist at SUNY College of Environmental Science and Forestry in Syracuse, N.Y., who has spent much of his career studying mound-building termites in southern Africa. The region’s charismatic safari animals have the “humble labors of all the termites” to thank for their survival, he adds.

Most of termites’ influence has to do with water. Like all animals, they have to stay hydrated. But unlike some animals, termites are particularly good at storing water for a dry day.

The insects have help from a different kind of organism: fungi. Researchers have found that termites cultivate a sort of fungus garden within their colony, built from chewed up grass and wood, and inoculated with fungal spores. The fungi are crucial to making termites such good wood eaters. They break down cellulose and lignin (both famously difficult-to-consume compounds) from the plant matter into more easily digestible nutrients.

Importantly for termites’ neighbors, those fungal structures can hold a lot of water. Inside a single colony, Dr. Turner says, there can be a reservoir of about 50 liters of liquid water. During the dry season or a drought, that moisture seeps out into the surrounds and helps organisms as mighty as trees survive.

That seepage can deplete the termites’ reservoir. But, Turner says, termites are particularly adept at gathering more, digging deep down into the ground when they have to, carrying water back to the surface in pouches in their abdomens.

The processes are thought to be similar in other places, such as the Bornean rainforest. But what about the increased nutrients Dr. Ashton and her colleagues found linked to termite activity?

Termites in southern Africa and beyond are known to help redistribute a massive amount of nutrients, too. They bring plant waste from deep in soils and over a wide area back to their mounds, making the structures nutrient hotspots. Then, when wind blows and rain falls, that healthy dirt is spread across the savanna.

One termite trait that enables the critters to be (sometimes) good neighbors is their sociability.

Termite colonies work together as a cohesive unit, explains Henderson, now an emeritus professor at LSU. “They’re doing things that make sense,” he says, like communicating and grooming one another, and calmly following the leader away from danger rather than fleeing in a frenzy. “It’s what’s allowed them to survive and be successful for so long.”

Living in harmony?

The dissonance between the benefits and costs of living with termites are uniquely felt in African agriculture. Termites are voracious grazers, and so are cattle. Farmers don’t always appreciate the competition.

Some farmers opt to wipe out the competitors. Others choose to coexist, often out of a recognition of termites’ propensity for enriching the topsoil.

But it’s not all about healthy dirt. When the mound-building termites are taken out, Turner explains, another kind of termite often takes its place. Entomologists call those “weedy” termites, because they’re more of a pest. While the mound-building termites Turner studies settle into a place for the long haul, a weedy termite colony plunders resources and then moves on to a new habitat conquest.

Termites are quite a diverse group worldwide. But most of the termites species in North America are similar to the African "weedy" termites, Turner says, which probably explains extreme disdain for them. Even Henderson advises not to let them get close.

“As cute as they are,” he says, “don’t let them get in your house. Just watch them in your yard.”