Ok, so the first thing I didn’t know was that termites are a type of cockroach. I had no idea.
The second thing – and this honestly makes a lot of sense, given what we know about termites – is that they apparently cross oceans every now and then.
Termites are a type of cockroach that split from other cockroaches around 150 million years ago and evolved to live socially in colonies. Today, there are many different kinds of termites. Some form large colonies with millions of individuals, which tend to live in connected tunnels in the soil. Others, including most species known as drywood termites, form much smaller colonies of less than 5000 individuals, and live primarily in wood.
Researchers from the Evolutionary Genomics Unit at the Okinawa Institute of Science and Technology Graduate University (OIST), alongside a network of collaborators from across the world, have mapped out the natural history of drywood termites—the second largest family of termites—and revealed a number of oceanic voyages that accelerated the evolution of their diversity. The research, published in Molecular Biology and Evolution, shines light on where termites originated and how and when they spread across the globe. It also confirms that some species have, in recent centuries, hitched a ride with humans to reach far-flung islands.
“Drywood termites, or Kalotermitidae, are often thought of as primitive because they split from other termites quite early, around 100 million years ago, and because they appear to form smaller colonies,” said Dr. Aleš Buček, OIST Postdoctoral Researcher and lead author of the study. “But very little is actually known about this family.”
Dr. Buček went on to explain how, before this study, there was very little molecular data on the family and the little understanding of the relationships between the different species that was known was based on their appearance. Previous research had focused on one genus within the family that contains common pest species, often found within houses.
To gain overarching knowledge, the researchers collected hundreds of drywood termite samples from around the world over a timespan of three decades. From this collection, they selected about 120 species, some of which were represented by multiple samples collected in different locations. This represented over a quarter of Kalotermitidae diversity. Most of these samples were brought to OIST where the DNA was isolated and sequenced.
Every now and then, I learn about a research project, and am given a new appreciation for the amount of work some scientists will do to expand our knowledge. There’s a degree to which some of this sort of thing can be less work than it necessarily sounds like. If I said I caught and measured hundreds of turtles every year, that could be just a couple weeks of work. That would be followed by a much longer period of analysis and whatnot, but a fairly small team can collect a lot of data in a very short time, if they know what they’re doing.
Doing it over 30 years, however, requires patience and persistence that I find admirable, not to mention reliable access to resources (funding educational and research institutions should be treated as a public investment in the future).
By comparing the genetic sequences from the different species, the researchers constructed an extensive family tree of the drywood termites.
They found that drywood termites have made more oceanic voyages than any other family of termites. They’ve crossed oceans at least 40 times in the past 50 million years, travelling as far as South America to Africa, which, over a timescale of millions of years, resulted in the diversification of new drywood termite species in the newly colonized places.
Furthermore, this study has cast doubt on the common assumption that drywood termites have a primitive lifestyle. Among the oldest lineages in the family, there are termite species that do not have a primitive lifestyle. In fact, they can form large colonies across multiple pieces of wood that are connected by tunnels underground.
“This study only goes to highlight how little we know about termites, the diversity of their lifestyles, and the scale of their social lives,” stated Prof. Tom Bourguignon, Principal Investigator of OIST’s Evolutionary Genomics Unit and senior author of the study. “As more information is gathered about their behavior and ecology, we’ll be able to use this family tree to find out more about the evolution of sociality in insects and how termites have been so successful.”
“They’re very good at getting across oceans,” said Dr. Buček. “Their homes are made of wood so can act as tiny ships.”
The researchers found that most of the genera originated in southern America and dispersed from there. It takes a scale of millions of years for one species to split into several after a move. The research also confirmed that, more recently, dispersals have largely been mediated by humans.
A good portion of my life has been spent learning about the ways in which humans move other species around, and the damage that can do. It’s neat to learn about species moving themselves around, over such vast distances.
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