Dr Sebastian Oberst. Image: Toby Burrows
Termites are a huge problem for Australia causing more than $1.5 billion in damage to homes every year. Hidden from sight, chomping their way through timber, one colony alone can run to more than 10 million workers, with the queen living for up to 25 years.
But, having been around for 120 million years – compared to a paltry six million that modern humans have been on Earth – termites have evolved some pretty interesting characteristics that we may be able to learn from.
Dr Sebastian Oberst, Senior Lecturer at the Centre for Audio, Acoustics and Vibration at the University of Technology Sydney (UTS), has been studying termites for nearly 10 years, including how they use vibration-sensing organs in their antennae and leg joints to communicate information.
“Termites are social insects with a need to communicate, which they do mainly via micro vibrations, using different signals and cues to share information,” Dr Oberst says.
When termites forage, they chisel, cut and chew timber, producing acoustic vibration signals, However, they keep this at an extremely low noise level to avoid detection, while being able to eavesdrop on their predators.
We are trying to understand the mechanical properties of these sensing organs in order to apply these to build and innovate hyper-sensitive vibration sensors.
— Dr Sebastian Oberst
Their crypticity is their main defence mechanism. It’s called competition avoidance, explains Dr Oberst. “For example, predatory ants walk very loudly compared to termites – which are about 100 times quieter – so termites eavesdrop on the vibrational cues from the ants’ footsteps to avoid them.”
Until now, the mechanisms that enable this amazing ability have been largely unknown. “We are trying to understand the mechanical properties of these sensing organs in order to apply these to build and innovate hyper-sensitive vibration sensors,” Dr Orberst says.
His research has not only helped to reveal some of the termites’ secrets but suggests tantalising real-world uses, including techniques that could replace chemical pest control.
Take the problem of termite infestation of wooden power line poles, of which there are around five million in Australia. Following the catastrophic St Patrick’s Day fires in Victoria in 2018, at least one termite-infested power pole was discovered to have ignited a blaze after a hollow pole snapped, bringing down power lines.
Giant termite (Mastotermes darwiniensis). Courtesy: scienceimage.csiro.au CC BY 3.0
If properly maintained, timber poles can last 40 to 60 years. Although poles are chemically impregnated to repel termites, the chemicals wear off after five to 10 years and termites can move in. This means regular inspections by specialists are required, which normally involve visual clues and tapping. However these techniques are far from foolproof.
The bio-dynamic, vibration-based termite devices developed at UTS are a potential solution to this huge challenge, says Dr Oberst. “By retrofitting these devices to poles we could constantly monitor, attack and control termites, preventing them colonising the wood and offering much greater security,” he says.
Avoiding the use of environmentally harmful chemicals also has a big advantage in domestic settings. Termites hide in houses, trees and wood and often aren’t detected until it’s too late – when a foot goes through a floorboard, for instance.
In another breakthrough of bio-dynamic modelling, Dr Oberst and his colleagues are developing quietly walking hexapods – a mechanical vehicle that walks on six legs and mimics the lightness of the termite footfall.
While the project is firstly about establishing the principle, and only then seeing how the hexapod can be adapted to serve different purposes, one application could be as a companion robot for individual soldiers on reconnaissance missions or in land mine detection and clearance operations. It also has implications for search and rescue operations. After earthquakes, for example, rescuers need to work very carefully in areas of unstable rubble to scan for what lies underneath.
From life-saving to life-enhancing, termites have lessons for us even in how they regulate their own built environment. Studying termite vibrations led Dr Oberst to examine termite mounds, finding sophisticated and complex design features that offer potential for innovation in artificial material design.
Termites keep air and temperature constant inside the colony. Little sacs in their heads hold water which is delivered to vents in the porous inner walls of their mounds that act like sponges. It means the mound is kept cool during the day while at night the system works to remove the buildup of gases such as carbon dioxide and methane produced by their bodies.
Based on these observations, Dr Oberst sees the opportunity to design and build termite-inspired materials with self-ventilation properties, such as bricks.
Small and secretive they may be, but termites clearly offer enormous potential for engineers to design and develop improved tools and materials that can be applied to a wide range of sciences and industries.
Reports/papers
Sebastian Oberst, Joseph C.S. Lai, Richard Martin, Benjamin J. Halkon, Mohammad Saadatfar, Theodore A. Evans (2020), Revisiting stigmergy in light of multi-functional, biogenic, termite structures as communication channel, Computational and Structural Biotechnology Journal, Vol.18, pp. 2522-2534
Sebastian Oberst, Michael Lenz, Joseph C.S. Lai, Theodore A. Evans (2019) Termites manipulate moisture content of wood to maximise feeding, Biology Letters, 15(7). 20190365.
Sebastian Oberst, Joseph C.S. Lai, Theodore A. Evans (2018) Key material properties in termite foraging, Journal of the Royal Society Interface, 15: 20180505.
Research team
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Senior Lecturer, Centre for Audio Acoustics and Vibration
Faculty
- Faculty of Engineering and Information Technology
- Centre for Audio Acoustics and Vibration
Funded by
- Australian Research Council
