A termite infestation can be troublesome for property owners. It’s estimated that termites cause over $50 billion in damage globally, every single year! Termites feed on cellulose (a component of wood), meaning that they will eat the wooden internal structures of a building. This makes them difficult to detect, as you will not see them in your pantry or kitchen like you would with other common pests. Also, they don’t like light, and they need a high level of moisture. This leads them to stay in dark, damp places, where people rarely look. Timber infested by termites will appear structurally sound from the outside but will be carved into a honeycomb pattern on the inside, making it much weaker. The termites will make their way to the finished side of the wood, but will then often stop without breaking through to the surface. All of this together means that termites can avoid being noticed until an infestation has become severe.

Termite Ecology

Termite shelter tunnels in a home.

Termites first evolved in the Jurassic or Triassic periods, around 150 million years ago, alongside the dinosaurs. Since then termites have managed to colonize every continent, with the exception of Antarctica. Although they might look similar to ants, their closest relatives are certain species of wood eating cockroaches. The social structure of a termite colony is also similar to an ant colony, with workers, soldiers, and reproductive castes. However, termites were actually the first social insects to evolve a caste system. Ants evolved their caste system later, which is a case of convergent evolution. To coordinate their massive colonies, termites mainly communicate using chemical pheromones, but can also communicate through vibrations and contact in an emergency. Most termite species around the world are not pests. Instead, they play a critical role in forest ecosystems by assisting with the natural decomposition of organic matter. They decompose so much matter that termites produce 11% of all methane in the atmosphere, which is a powerful greenhouse gas. In addition to eating “wild” cellulose, some species of termites (but none in Canada) practice a form of agriculture by tending crops of Termitomyces fungus. It’s believed that termites first started this practice over 30 million years ago.

Termites face an enormous number of predators, ranging from mammals and amphibians to scorpions and spiders. The greatest hunters of termites are ants, despite the similarities between the species. Some ant species even undertake organized raids on termite nests. Beyond predators, termite colonies will also fight each other for territory and food resources. When the tunnels of two termite colonies intersect, it can create a tense situation. Often, worker termites will pour into the intersection to block the connection between the colonies with their bodies, preventing hostilities.

Termites in Toronto

Termite drop tunnels.

The termites which are present in Toronto are the Eastern Subterranean Termite species. Unfortunately, Eastern Subterranean Termites often cause damage to manmade structures. They are native to the Eastern United States, and Southern Ontario is currently the northern edge of their range, as termites are unable to survive cold climates. The Eastern Subterranean Termite is an invasive species in Canada, Europe, South America, and the Bahamas. It is believed that they arrived in Toronto on ships from the United States, docked in the Toronto Harbour near Cherry Street. They slowly spread throughout the downtown, pockets of the Greater Toronto Area, and other towns in Southwestern Ontario. In Toronto, their presence was first noticed in the 1970s, and the city passed a bylaw which gave homeowners grants for termite treatment. Those grants were stopped in 1999. Due to global warming and increased international trade we are starting to see more termite sightings in new locations in the GTA, and even some sightings in other parts of Canada.

Termite Life Cycle

A worker termite.

All termites begin their lives as eggs, laid by their colony’s reproductive individuals. From eggs they hatch into larvae, which are very similar to workers in appearance. They can even function as workers before fully developing. Most larvae will grow and molt a number of times before developing into an adult worker, which comprise the vast majority of the colony. Workers are ivory coloured, about 6 millimetres long, with a thick waist. They can appear like a walking grain of rice, but with the distinct outline of the digestive tract visible through their opaque abdomen. Their mouth parts are adapted for chewing, and they are responsible both for foraging for food, and for feeding the members of the colony who cannot feed themselves. It is the worker caste which causes structural damage. Larvae can also more rarely develop into soldiers, which requires a greater number of molts. Soldiers have a similar size and colour to workers, but their head is greatly enlarged, and their mandibles have become larger and stronger. This lets them defend the colony against predators but comes at a cost. Soldier termites lose the ability to feed themselves and are dependent on worker termites to do it for them.

A termite queen.

Larvae even more rarely develop into nymphs, which are an intermediate stage between a larva and a reproductive individual. After even more molts, a nymph will finally develop into either a secondary or primary reproductive. Secondary reproductives, or secondary queens and kings, do a significant portion of the egg-laying for an established colony, but are unable to establish new colonies themselves. If the primary king or queen of the colony dies, a secondary reproductive will generally take their place. Primary reproductives, also known as alates (from the Latin word for “winged”), are both male and female. They develop two sets of equally long, smoky grey wings and leave the colony to swarm in the air, until they pair up with a mate. The pair will then fly away to found a new colony together. Alates are dark brown to black in colour, which makes it easy to mistake them for flying ants. Once a colony has been established, the male alate is called the king, and the female alate is called the queen. Both will lose their wings, and the queen’s abdomen will grow much larger until it is immobile. Termite kings and queens mate for life, and termite queens are the world’s longest living insects, with some reportedly reaching 30 to 50 years old. The queen is able to lay hundreds of eggs every day, increasing the size of the colony.

Termite Infestations

A termite shelter tube

Termite colonies are not well-defined areas, instead they consist of a widely spread series of tunnels and galleries. They can extend for up to 2000 square metres and house 750,000 to 4,500,000 individual termites. Foraging workers travel below ground in tunnels, and above ground in shelter tubes constructed from soil particles cemented together with a secretion from the workers’ glands. Termites will eat anything containing cellulose but will tunnel through materials which do not contain cellulose (such as foam insulation) to obtain food on the other side. Once a colony gains access to a steady supply of cellulose, such as the wood frame of your house, it can consume half a kilogram (or just over a pound) of wood every day. When present in a home, Eastern Subterranean Termites will be found near, at, or under ground level. They tend to not venture into the heights of a structure unless they find a source of moisture.

There are several risk factors which can make your home more vulnerable to termites. Hollow block foundations allow termites to get inside the hollow blocks and easily travel up into the house. Slab foundations put your home close to the soil, so any holes or cracks will can be exploited by termites building shelter tubes into the house. Inaccessible crawlspaces provide a perfect environment for colonies, with their humidity and darkness. Also, they are difficult for people to inspect and treat. Earth and rubble filled porches create a highway for termites directly from the soil to the walls of a house. Finally, wood to soil contact is the greatest risk factor for a termite infestation. 90% of termite infestations can be directly linked to wood in soil, such as door frames, deck posts, or porch supports. These provide food, moisture and shelter: everything a termite colony could want!

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