The discovery in China of two spectacular sites full of ancient fossilized insects has revealed that shortly after the great extinction of the Permian-Triassic there was an explosion in the diversity of these species. The first insects on record lived in the Devonian just over 400 million years ago, and since then, they have become the most successful living creatures on Earth.
Experts at the Royal Entomological Society of London estimate that, on average, in every square kilometer of the planet we could find 10 billion insects. So far, more than 750,000 species have been described, but some researchers, like Terry Erwin, an entomologist at the Smithsonian Institution, are convinced that there can be up to 30 million.
Ancient insects found in China shed more light on insects evolution
The discovery of two broad sets of ancient fossilized insects in China could shed some light on the proliferation of these creatures.
In fact, one of the first conclusions reached by the scientists who studied the remains, led by a team from the Nanking Institute of Geology and Paleontology, is that after the massive extinction that took place 252 million years ago, during the Permian-Triassic, when 70% of terrestrial vertebrates and 90% of marine species perished, there was an explosion of diversity among prehistoric insects.
That coincided with a similar proliferation recorded by plants.
Insects proliferated much earlier than initially believed
Before the Great Extinction, there were already many different varieties of insects, such as beetles or dragonflies, but it is not easy to know which survived the cataclysm. The anatomical structures of these animals are not as well preserved as bones, so there are not many ancient insects fossils to study.
However, the paleontologists of the before-mentioned Chinese institution and their collaborators found two sites in the northwest of the Asian country in which all kinds of remains could be examined, from larval sheaths to wings.
The study concluded that certain ancient insects, such as some sort of beetles, survived extinction, but that many others evolved shortly after that. That would have happened much earlier, at around 237 million years ago, by 100 million years before the previous scientific estimates.