Washington: A new research has shown that beetles first appeared on Earth at the same time as the earliest dinosaurs but turned out to be much better survivors.
Researchers said that today, there are an estimated 350,000 known species of beetle on Earth, and probably several million more yet to be discovered. The insects account for about a quarter of all life forms on the planet.
Researchers have debated over the reason for the existence of this large number of beetle species but never found an answer.
Now, a research team has shown that large numbers of modern-day beetle lineages evolved very soon after the first beetles originated, and have persisted ever since. Many modern-day lineages first appeared during the Jurassic period, when the major groups of dinosaurs appeared too.
“The large number of beetle species existing today could very well be a direct result of this early evolution and the fact that there has been a very high rate of survival and continuous diversification of many lineages since then,” said
Professor Alfried Vogler from Imperial College London’s Department of Life Sciences and the Natural History Museum’s Department of Entomology, and lead author of the study.
The team used DNA sequencing and fossil records to compile a comprehensive evolutionary ‘family tree’ for beetles.
By comparing DNA sequences from 1,880 beetle species, the team was able to group beetle species that are descended from a common ancestor, enabling them to build an evolutionary tree for all the species included.
Fossils of known ages were then used to date key moments of evolution and diversification on the tree.
Previously, the survival success of beetles had been attributed to herbivory - feeding on plants - and the rise of flowering plants in the Cretaceous era, which started some 140 million years ago.
However, mapping species numbers onto the evolutionary tree shows that many modern beetle lineages significantly pre-date the appearance of the first flowering plants.
Professor Vogler said that beetles have displayed an exceptional ability to seize new ecological opportunities and develop a great range of life styles and feeding types.
“Unlike the dinosaurs which dwindled to extinction, beetles survived because of their ecological diversity and adaptability,” he said.
The team said that understanding the evolution of beetles is an important part of understanding the natural world.
“With beetles forming such a large proportion of all known species, learning about their relationships and evolution gives us important new insights into the origin of biodiversity and how beetles have triumphed over the course of nearly 300 million years,” Professor Vogler said.
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