Termites are portrayed (rightly so) as one of the most invasive pests to Carolina homeowners, and they might lead one to ask “are there any benefits to termites”? It turns out that in addition to being an important member of the natural food chain, they also have some important benefits to science and engineering.
Naturally, most of us may find that hard to believe, but at Nelon-Cole we value every avenue of education in the pest and moisture control industry and are happy to share knowledge with both our staff and technicians as well as our loyal customers.
can we learn anything from such destructive pests as termites?
THE TERMITE MOUND
Though a typical termite nest or mound found around Carolina homes is typically far smaller, there are termite mounds that can reach between 10-15 feet, with the largest known examples extending up to 20 feet in the air. Such examples are not likely to be found in our region, but such examples do indeed exist. When considering that the typical ‘worker’ termite is mere millimeters in size, such a nest can be a bit of a natural marvel indeed. But how is this done, how are these nests so strong and resilient to the elements, and what can we learn from their construction techniques?
Recently, a team of researchers at Caltech undertook an extensive study of exactly this phenomenon. The research, led by Chiara Daraio, G. Bradford Jones Professor of Mechanical Engineering and Applied Physics and Heritage Medical Research Institute Investigator, was recently published in the journal Science in August. Some of the conclusions reached include "Termites are only a few millimeters in length, but their nests can stand as high as 4 meters—the equivalent of a human constructing a house the height of California's Mount Whitney," says Daraio. If you peer inside a termite nest you will see a network of asymmetrical, interconnected structures, like the interior of a loaf of bread or a sponge. Made of sand grains, dust, dirt, saliva, and dung, this disordered, irregular structure appears arbitrary, but a termite nest is specifically optimized for stability and ventilation. We thought that by understanding how a termite contributes to the nest's fabrication, we could define simple rules for designing architected materials with unique mechanical properties,"
though uncommon in the Carolinas region, some termite mounds can grow to enormous sizes
Disordered structures, like that of a termite nest, are more prevalent than periodic structures and often show superior functionalities, but, until now, engineers had not figured out a reliable way to design them.
"The way we first approached the problem was by thinking of a termite's limited number of resources," says Daraio. When it builds its nest, a termite does not have a blueprint of the overall nest design; it can only make decisions based on local rules. For example, a termite may use grains of sand it finds near its nest and fit the grains together following procedures learned from other termites. A round sand grain may fit next to a half-moon shape for increased stability. Such basic rules of adjacency can be used to describe how to build a termite nest. "We created a numerical program for materials' design with similar rules that define how two different material blocks can adhere to one another," she says.
This algorithm, which Daraio and team dub the "virtual growth program," simulates the natural growth of biological structures or the fabrication of termite nests. Instead of a grain of sand or speck of dust, the virtual growth program uses unique materials' geometries, or building blocks, as well as adjacency guidelines for how those building blocks can attach to each other. The virtual blocks used in this initial work include an L shape, an I shape, a T shape, and a + shape. Additionally, the availability of each building block is given a defined limit, paralleling the limited resources a termite might encounter in nature. Using these constraints, the program builds out an architecture on a grid, and then those architectures can be translated into 2D or 3D physical models.
"Our goal is to generate disordered geometries with properties defined by the combinatory space of some essential shapes, like a straight line, a cross, or an 'L' shape. These geometries can then be 3D printed with a variety of different constitutive materials depending on applications' requirements," says Daraio.
WHAT ARE THEY MADE OF
Researchers at Caltech aren’t the only ones who have performed in-depth studies of termite mounds. Other studies in the past have also yielded information that is important to materials science, engineering, and other scientific fields. We have learned that termite mounds are primarily composed of termite saliva, feces, and clay. Termites carefully construct mounds that are composed of a series of tunnels for airflow and also traveling when they are foraging for food.
Scientists have also detailed the nest building in a common South American termite, Cornitermes cumulans (Kosarinsky 2011). The beginning stages of this termite colony’s nest are subterranean with a small portion above ground made of sand and clay materials. As the termites continue to build up the mound, the microstructure and wall porosity changes with height, and, in this case, the termites built a mound about 1.5 meters high. The walls are very porous, hence facilitating airflow.
In many cases, nature (e.g., other insects) can provide insight into human-mediated design. Some architects and engineers are studying the structures of termite mounds to potentially design buildings (particularly high rises) with greater energy efficiency. How the mounds are constructed to provide internal ventilation may be useful for future designs to reduce the need for air conditioning.
WHY TERMITES CONSTRUCT SUCH LARGE NEST AREAS
Termites thrive by living in large colonies and must maintain acceptable levels of temperature, moisture, and air quality to survive. In some termite colonies that live symbiotically with fungi, a temperature of around 86 degrees Fahrenheit must be maintained for optimal growth and survival. Inside the termite mounds are air channels that promote ventilation and circulation of air to increase gas exchange and improve thermoregulation. The fungi receive food, water, and shelter from the termites in exchange for their digestion of cellulose for the termites.
Heat is produced by the fungi and termites and this heat must be dissipated to maintain an acceptable temperature. In general, there are thin buttress-like “chimneys” surrounding the wider core of the mound. In savannah-type environments, the outer chimneys are warmer and release heat during the sunny daytime hours, while the core is warmer during nighttime. Some scientists believe that, during daytime hours, the warmer air rises through the chimneys and pushes cooler air down into the core, hence providing ventilation. Other scientists believe that the smaller tunnels allow external air to flow in and out of the mound, hence introducing fresh air and maintaining the mound’s appropriate temperature.
The termite young and fungus inhabit the lower levels of the mound, but termites will travel to the upper parts of the mound to repair areas that have become damaged by weather or other means.
Termite colonies that build their mounds in an open savannah environment where temperatures are relatively high would have thinner walls and taller mounds to improve ventilation. For termite colonies building nests in a shaded forest environment, these mounds may have thicker walls and shorter heights to improve thermoregulation.
EXTENSIVE NETWORKS OF TERMITES
Termite mounds and colonies can thrive to absolute monolithic proportions under perfect conditions, and there is perhaps no better example than a find in 2004 in Brazil. The discovery of an enormous network of more than 200 million termite mounds, some of them about 4,000 years old, is like finding an "undiscovered wonder of the world," according to the lead researcher with the team that found it.
"The first time I was there, it's just unbelievable. You just cannot believe what you're looking at," said Stephen Martin, a social entomologist and professor at Salford University in the U.K. The mounds were discovered in a remote forest in northeastern Brazil, stretching across an area the size of Great Britain. They can be seen from space. They're all roughly 10 feet high, 20 feet wide at the base and spaced at 30 or 40-foot intervals. Martin first noticed the mounds in 2004, while he was researching the decline of honey bees in the region. Each mound of soil contains a single vertical shaft that allows termites to move between the surface and the underground network of tunnels.
though uncommon in our region, termites can build vast visible networks of nests
As Martin's team began to excavate these tunnels, they found several "galleries" filled with stockpiles of dried leaves or young, baby termites in the process of being reared. The region's rainy season only lasts about one month out of the year, so the termites need to gather as much vegetation and other food as possible in that short period. Martin thinks the termites were able to build such an enormous network because of the remoteness of the region.
Termites are certainly a well-known and very controllable pest here in the Carolinas. Indeed, Nelon-Cole has become your local award-winning expert when it comes to keeping your home safe from the destructive nature of these insects. But clearly, termites can operate with a collective instinct or intelligence that can both surprise and benefit scientific study – even as we work hard to keep them away from your home or business!
nelon-cole keeps your home safe from termite and pest problems
Are you having (or suspect you may have) termite issues in your home or business in the Carolinas? Call the Carolina pest control experts at Nelon-Cole today and get a FREE consultation on how we can eliminate fall pest concerns in your home – and protect you from further pest and moisture control issues in the Carolinas in the future!
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