Thanks to Yonatan and Eilee for this week’s suggestion!

Further reading:

Worker termites [photo from this site]:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week we have a topic I’ve been wanting to cover for a while, suggested by both Yonatan and Eilee. It’s the termite episode!

We talk a lot about animals that eat termites, and in many cases termite-eating animals also eat ants. I’ve always assumed that termites and ants are closely related, but they’re not. Termites are actually closely related to cockroaches, which are both in the order Blattodea, but it’s been 150 million years since they shared a common ancestor. They share another trait too, in that no one wants either insect infesting their house.

Like most cockroach species, though, most termite species don’t want anything to do with humans. They live in the wild, not in your house, and they’re incredibly common throughout most of the world. That’s why so many animals eat termites almost exclusively. There are just so many termites to eat!

There are around 3,000 species of termite and about a third of them live in Africa, with another 400 or so in South America, 400 or so in Asia, and 400 or so in Australia. The rest live in other parts of the world, but they need warm weather to survive so they’re not very common in cold areas like northern Europe.

A termite colony consists of a queen, soldiers, and workers, which sounds very similar to ants, but there are some major differences. Worker termites take care of the nest and babies, find and process food so the other termites can eat it, and store the processed food. They also take care of the queen. Unlike ants and bees, worker termites aren’t only female and aren’t always sterile. Soldiers are bigger and stronger than workers, with much bigger heads and jaws so they can fight off potential predators. In some species, the soldiers have such big jaws that they can’t actually eat without help. Worker termites feed them. Finally, the queen is the largest individual in the colony, usually considerably larger than workers, but unlike queen bees and ants, she has a mate who stays with her throughout her life, called a king. Some termite queens can live to be as much as 50 years old, and she and the king spend almost their entire lives underground in a nesting chamber.

The larger the colony, the more likely it is that the colony has more than one queen. The main queen is usually the one that started the colony along with her king, and when it was new they did all the work—taking care of the eggs and babies, foraging for food, and building the nest itself. As the first workers grew up, they took on more of those tasks, including expanding the nest.

Workers are small and their bodies have little to no pigment, so that they appear white. Some people call them white ants, but of course they’re not ants. Workers have to stay in a humid environment like the nest or their bodies dry out. Workers and soldiers don’t have eyes, although they can probably sense light and dark, and instead they navigate using their antennae, which can sense humidity and vibrations, and chemoreceptors that sense pheromones released by other termites.

Termites have another caste that’s not as common, usually referred to as reproductives. These are future kings and queens, and they’re larger and stronger than workers. They also have eyes and wings. When outside conditions are right, usually when the weather is warm and humid, the reproductive termites leave the nest and fly away. Males and females pair off and search for a new nesting site to start their own colony.

Termites mainly eat dead plant material, including plant material that most other animals can’t digest. A termite’s gut contains microbes that are found nowhere else in the world, which allow the termite to digest cellulose found in plants, especially wood. Baby termites aren’t born with these microbes, but they gain them from worker termites when the babies are fed or groomed.

In some areas termites will eat the wood used to build houses, which is why people don’t like them, but termites are actually important to the ecosystems where they live, recycling nutrients and helping break down fallen trees so other plants can grow. They also host nitrogen-fixing bacteria, which are important to plant life.

A recent study in Australia determined that termites are really important for rainforest health. In some parts of Australia, conservation groups have started planting rainforest trees to restore deforested areas. Decomposers like termites are slower to populate these areas, with one site that was studied 12 years after planting showing limited termite activity. That means it takes longer for fallen branches, logs, and stumps to decay, which means it takes longer for the nutrients in those items and others to be available for other plants to use.

The problem seems to be that the new forests don’t have very many dead trees yet, so the termites don’t have a lot to eat. The team is considering bringing in fallen logs from more established forests so the termites have food and can establish colonies more easily.

Some species of termite in Africa, Australia, and South America build mounds, and those mounds can be huge. A mound is built above ground out of soil and termite dung, held together with termite saliva. It’s full of tunnels and shafts that allow the termites to move around inside and which bring air into the main part of the nest, which is mostly below ground. Different species build differently-shaped mounds, including some that are completely round.

Some termite mounds can be twice the height of a tall person, and extremely big around. The biggest measured had a diameter of almost 100 feet around, or 30 meters. But in at least one place on earth, in northeastern Brazil, there’s a network of interconnected termite mounds that is as big as Great Britain.

The complex consists of about 200 million mounds, each of them about 8 feet tall, or 2.5 meters, and about 30 feet across, or 9 meters. They’re just huge piles of soil excavated from underground, and tests have determined that the mounds range in age from 690 years old to at least 3,820 years old and are connected by tunnels–but the nests under the mounds are still in use!

Not all termite species build mounds or even live underground. A group called drywood termites live in wood and usually have much smaller colonies than other termites. They probably split off from other termites about 100 million years ago, and a 2022 genetic study determined that they probably originated in South America. But drywood termites have spread to many other parts of the world, and scientists think it’s because their homes float. They estimate that over the last 50 million years, drywood termites have actually floated across entire oceans at least 40 times. When their floating log homes washed ashore, the termites colonized the new land and adapted to local conditions.

A lot of people worry that termites will damage their homes, but in many parts of the world, people eat termites. The termites are fried or roasted until they’re nicely crunchy, and they’re supposed to have a nut-like flavor. They’re also high in protein and important fats. So the next time you worry about your house, you can shout at any potential termites that if they’re around, you might just eat them as a snack.

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Thanks for listening!

Episode 446: Termites