Drywood termites are great travelers. According to a recent study published in the journal Molecular Biology and Evolution , these creatures have successfully traversed the ocean at least 40 times in the last 50 million years. How have they achieved it? A team of scientists seems to have the answer.
Although they have the ability to fly, termites are not good at covering long distances. These animals have used other tricks to cross the oceans. “The dispersal ability of Kalotermitidae is due to their lifestyle, as they often nest and feed on individual pieces of wood , which can float across oceans like rafts,” the team write in their paper. “Their houses are made of wood, so they can act like little ships.”
The researchers explain this by giving the example of what happened on the Krakatau Islands in Indonesia in 1883. That year a volcanic eruption devastated the area, but multiple species of drywood termites recolonized it after only 100 years.
“Most extant species of Kalotermitidae are unable to forage outside their nesting piece of wood. Instead, they form small colonies on wooden items such as dead branches of live trees,” the researchers write.
To test this, the team didn’t put drywood termites in small boats and let them set sail. Instead, they looked at the genetics of the drywood termite family Kalotermitidae and mapped how their mitochondrial DNA traveled around the world.
Analyzing hundreds of drywood termite samples from around the world collected over the last 30 years, the researchers focused on some 120 termite species, accounting for 27% of the diversity of Kalotermitidae and almost all genera, giving the team a lot of information to work with.
“Drywood termites or Kalotermitidae are often considered primitive because they split off from other termites very early, around 100 million years ago, and because they seem to form smaller colonies,” says study lead author Aleš Buček, an evolutionary geneticist at the Okinawa Institute of Science and Technology (OIST) Graduate University in Japan. “But actually very little is known about this family.”
By genetically tracing their family tree, the researchers found that the first common ancestor lived 84 million years ago. This means that some of the earliest splits in the family tree could have occurred on land before the Gondwana supercontinent finished breaking up. Gondwana is the name given to an ancient southern continental block that existed since the Neoproterozoic (about 550 million years ago).
However, most of the 40 splits occurred less than 50 million years ago, suggesting that these small animals traveled by sea . More recently, human travel may also have helped termites get around.
Kalotermitidae typically nest in small groups on a single piece of wood, which many researchers have interpreted as the “original” way of living for termites, before larger and more complex colony organizations evolved. However, according to the researchers, some of the oldest lineages in the genetic family foraged for food on multiple pieces of wood, suggesting that the single-piece-of-wood strategy might be a relatively new adaptation, possibly driven by competition.
“This study only highlights how little we know about termites , the diversity of their lifestyles and the scale of their social life,” says OIST ecologist Tom Bourguignon. “As more information about their behavior and ecology is gathered, we will 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.”
Referencia: Buček, A. 2022. Molecular Phylogeny Reveals the Past Transoceanic Voyages of Drywood Termites (Isoptera, Kalotermitidae). Molecular Biology and Evolution. DOI: https://doi.org/10.1093/molbev/msac093
