From what other insects did termites evolve? South African naturalist Eugène Marais’ The Soul of the White Ant, first published in 1925, is a classic entomological research text. However, recent studies have shown that Marais got one very important detail of his book wrong: termites are not related to ants at all.
Termites may look like ants, and they may live much like ants, but they share their family tree with another insect that plagues human beings no matter where they live: the cockroach.
Termite phylogeny and taxonomy: a long story
The link between cockroaches and termites is not necessarily a new discovery. As early as 1934, entomologist L.R. Cleveland hypothesized that termites might share a common ancestry, or phylogeny, with wood-eating cockroaches (Cryptocercus).
Cleveland didn't just base his hypothesis on the fact that the two insects share a plant-based diet. Rather, Cleveland was convinced by the fact that both Cryptocercus and termites had developed a symbiotic relationship with a microorganism that lives in the intestinal tract of both insects and is actually responsible for their ability to digest cellulose.
Flash forward almost 70 years to an era in which scientists can analyze actual DNA. In 2007, Paul Eggleton and his colleagues proposed that, based on new genetic discoveries, termites no longer be classified as a separate order of insects (Isoptera), but as a family (Termitoidae) within the same order as cockroaches (Blattodea).
Eight years later, researchers from the National University of Singapore published the results of their sequencing the genomes of 66 separate termite species, revealing conclusively that termites and cockroaches have a common ancestor.
Pangea, continental drift and diversification of species: an even longer story
To understand how termites evolved from cockroaches, we have to go back in time nearly 200 million years to the middle of the Jurassic period. Back then, the Earth was dominated by a titanic landmass called Pangea that gradually broke apart to form the seven continents of the present day. As it did, it may have forced cockroaches to branch off and adapt to changing environmental conditions by learning to cooperate.
Over the course of the next 120 million years, the planet’s climate turned cooler and drier, the dinosaurs were driven to extinction, and termites, as we know them, appeared. In fact, the oldest termite colony on record comes from this era, known as the Upper Cretaceous. In 1986, geologists in West Texas discovered this termite colony. Some scientists even believe that termites may have made their way from the tropics of ancient Africa to places as far away as Texas by traveling across the ocean on rafts of rotting logs. Whatever the case, "modern" termites are actually thought to be about 50 million years old.
Cockroaches and termites today
If Eugène Marais were alive today, what common traits might he observe between cockroaches and termites? Despite termites having evolved from cockroaches, not many. Cockroaches are not nearly as social as termites, and they certainly do not organize themselves into castes (queen, soldier, worker) as termites do.
However, Cryptocercus, the termite’s closest living relative, does engage in several behaviors more characteristic of termites. Both insects emerge from their eggs as altricial young (nymphs), meaning they must be nursed and protected by adults who are capable of foraging. Even these adult Cryptocercus and termites will share their food, via a practice known as trophallaxis.
And both insects place a high premium on keeping clean. Grooming is a necessity for creatures that spend the majority of their time sorting through plant litter and debris. Allogrooming, the animal world’s version of “if you scratch my back, I’ll scratch yours,” also serves to reinforce social roles and power structures within the group.
Finally, Cryptocercus and termites are actually beneficial insects in the right environment. Not only do they aid in the formation of soil by breaking down organic materials, but they also help feed bird and mammal species who get their protein from these bugs.