Study: Termites may have a bigger role in future ecosystems

Subterranean Asian termite (Coptotermes Gestroi) soldier in a cartoon nest. C. gestroi is a termite that feeds on wood. Image credit: Thomas Chouvenc

Most people think of termites as a wood-consuming nuisance in homes and businesses. But those termites represent less than 4% of all termite species worldwide.

Termites are critical in natural ecosystems—particularly in the tropics—because they help recycle dead wood from trees. Without such a rottenness, the world would be crammed with dead plants and animals.

New research suggests that these energetic wood-consuming insects could soon move toward the Arctic and Antarctic as global temperatures rise due to climate change.

Wood-feeding termites from far north Queensland, Australia.  Original photos by Rebecca Clement.  Artwork by Donna Davis
Wood-feeding termites from far north Queensland, Australia. Original photos by Rebecca Clement. Artwork by Donna Davis

In a new international study led by the University of Miami and including a co-author from the University of Michigan, researchers have learned that termites play a pivotal role when it comes to decomposing wood, contributing to the carbon cycle on Earth. They also learned that termites are very sensitive to temperature and precipitation, so as temperatures rise, the insect’s role in decomposing wood is likely to expand beyond the tropics.

“As temperatures rise, the impact of termites on the planet can be enormous,” said study leader Amy Zahn, a professor of biology at the University of Miami.

University of Michigan biologist Amy Claassen is a co-author of the study, which was published online Thursday in the journal Science. She led a team that investigated a field site in Vermont.

Biologist at UM Aimée Classen Aimée Classen
Amy Klassen

“We know that species are moving due to warming and changes in precipitation, but we don’t know much about what these movements might mean for ecosystems and carbon interactions,” said Clasen, professor in the Department of Ecology and Evolutionary Biology and director of the university. From Michigan Biological Station.

“This study is one of the first to connect the dots between species movement, changes in ecosystem process, and climate change to show that the movement of an organism as small as termites can creep up to influence the rate of wood — a global carbon stock — decomposing.”

For the study, more than 100 collaborators studied sites around the world where bacteria, fungi, and termites consume dead wood. They also investigated how temperature and precipitation affect wood detection and decay using the same experimental setup at more than 130 sites in a variety of habitats across six continents. Their results suggest that areas with high termite activity should increase as the ground becomes warmer and drier.

“Termites were most influential in places such as tropical savannas, monsoon forests, and subtropical deserts,” Zahn said. “These systems are often underestimated in terms of their contribution to the global carbon budget.”

Collaborator Amy Austin, of the University of Buenos Aires, said the global study helped scientists get a broader view on wood decay.

“The inclusion of hot and arid biomes, particularly in the Southern Hemisphere where termites are abundant and active, allowed new insight into their role in carbon circulation,” she said. “As ecologists, we may need to broaden our view of woody ecosystems beyond the closed canopy forest and realize that woody carbon stores in drier ecosystems are an important component of the global carbon cycle.”

A mass of radioactive pine, partly eaten by termites, from far north Queensland, Australia.  Image credit: Rhiannon Dalrymple
A mass of radioactive pine, partly eaten by termites, from far north Queensland, Australia. Image credit: Rhiannon Dalrymple

Although both microbes and termites decompose dead wood, there are important differences between them. While microbes need water to grow and consume wood, termites can operate at relatively low humidity levels. In fact, termites can search for their next meal even if it is dry. They carry what they want back to their piles, or even move their colony to the woods they consume.

Subterranean termites (Coptotermes acinaciformis) mound on Cullen's Ironbark tree (Eucalyptus cullenii) with University of Miami doctoral student Abe Yatesko in Brooklyn Reserve, Mountain Carpine, Queensland, Australia.  Image credit: Rebecca Clement
Subterranean termites (Coptotermes acinaciformis) mound on Cullen’s Ironbark tree (Eucalyptus cullenii) with University of Miami doctoral student Abe Yatesko in Brooklyn Reserve, Mountain Carpine, Queensland, Australia. Image credit: Rebecca Clement

“Microbes are globally important when it comes to decomposing wood, but we have largely overlooked the role of termites in this process,” Zahn said. “This means that we do not take into account the huge impact that these insects could have on the future carbon cycle and interactions with climate change.”

Like young cows, termites release carbon from wood as methane and carbon dioxide, two of the most important greenhouse gases. Therefore, termites may increasingly contribute to greenhouse gas emissions with climate change, according to the researchers.

“I am fascinated by how the decomposition of microbial wood and termites affects how carbon is released back into the environment,” said Zahn, who has studied the effects of carbon release from wood for more than a decade.

Klassen said being part of a global science team has been rewarding and has yielded a lot of valuable data.

“Being part of a global network of scientists who are all working on the same questions enables our group to understand local patterns as well as global patterns,” she said. “This bottom-up approach to addressing scientific questions packs a powerful punch. For a small investment in time or money from any one group, we gain a great understanding of what the world might look like in the future.”