Climate Change: Place of Termites in Shaping the Ensuing Crisis
As the debate over climate continues with concerns over its implications across continents, a measure of relief could come from an unexpected source- TERMITES!
Termite mounds may help protect arid landscapes in Africa from turning into deserts as climate change exacerbates droughts.
In the parched grasslands and savannas, or drylands, of Africa, South America and Asia, termite mounds store nutrients and moisture, and — via internal tunnels — allow water to better penetrate the soil. As a result, vegetation flourishes on and near termite mounds in ecosystems that are otherwise highly vulnerable to “desertification,” or the environment’s collapse into the desert.
Princeton University researchers report in the Journal of Science that termites slow the spread of deserts into dry lands by providing a moist refuge for vegetation on and around their mounds. They report that dry -lands with termite mounds can survive on significantly less rain than those without termite mounds. The research was inspired by fungus-growing termites of the genus Odontotermes, but the theoretical results apply to all types of termites that increase resource availability on and/or around their nests.
Corresponding author Corina Tarnita, a Princeton assistant professor in ecology and evolutionary biology, explained that termite mounds also preserve seeds and plant life, which helps surrounding areas rebound faster once rainfall resumes. “The rain is the same everywhere, but because termites allow water to penetrate the soil better, the plants grow on or near the mounds as if there were more rain,” Tarnita said.
Surprisingly, man has some other things to learn from termites!
Termite construction projects have no architects, engineers, or foremen, yet these centimetre-sized insects build complex, long-standing, meter-sized structures all over the world. How they do it has long puzzled scientists.
Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences and the Department of Organismic and Evolutionary Biology have developed a simple model that shows how external environmental factors, such as daytime temperature variations, cause internal flows in the mound, which move pheromone-like cues around, triggering building behaviour in individual termites. Those modifications change the internal environment, triggering new behaviours and the cycle continues.
This new framework demonstrates how simple rules linking environmental physics and animal behaviour can give rise to complex structures in nature. It sheds light on broader questions of swarm intelligence and may serve as inspiration for designing more sustainable human architecture.
The research is published in the Proceedings of the National Academy of Sciences.
“Our theoretical framework shows how living systems can create micro-environments that harness matter and flow into complex architectures using simple rules, by focusing on perhaps the best-known example of animal architecture — termite mounds,” said L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, professor of organismic and evolutionary biology and of physics, and senior author of the study. “As Winston Churchill once said ‘We shape our buildings and thereafter they shape us.’ We can quantify this statement by showing how complex structures arise by coupling environmental physics to simple collective behaviours on scales much larger than an organism.”
While they might look like apartment complexes, termite mounds actually function as a ventilation system for the colony that lives deep underground. In previous research, Mahadevan and his team found that changes in external temperatures throughout the day drive changes in air flow, temperature, and humidity inside the mound.
These changes in air flow carry information-containing odours to termites inside the mound. These information clouds — made up of pheromones and metabolic gases such as carbon dioxide — tell termites where to adjust the mound. If, for instance, one section of the mound is too warm, that temperature change will trigger a change in airflow, which will carry construction cues to nearby workers. The termites will follow their senses to that section and adjust the mound to reduce temperature. That change in temperature will change the airflow and the termites will change their behaviour.
By quantifying this feedback loop, the model developed by the Mahadevan group presents a minimal description that captures the essential features of mound morphogenesis and generates a wide range of typical mound morphologies.
“The wide array of termite mound shapes and sizes predicted by our model reflects the diverse range of mound morphologies observed in nature,” said Alexander Heyde, a Harvard PhD student and co-first author of the study. “Some mounds are tall and narrow, while others are small and compact. Depending on the physical and behavioural parameters at play, the mounds of different termite species can look remarkably different.”
“Our model presents a simple answer to a long-standing question in termite ecology, a field which already inspires and informs the interdisciplinary communities of bio-inspired engineering and swarms intelligence. This research challenges us to learn how to build sustainable architectures that harness, rather than fight, the natural variations in our environment,” said Mahadevan.