Beetles can be found in most ecosystems, from the local parks to tropical rainforests and the Arctic tundra. They are the most diverse group of animals ever known to exist, with almost 400 thousand species already described. This immense diversity has puzzled scientists for centuries. Famous figures such as Charles Darwin or Alfred Russel Wallace drew inspiration for their evolutionary theories from the study of beetles.
However, understanding the origins and evolution of beetles is complicated. By using a previously published and carefully curated 68-gene dataset, a research team led by the University of Bristol were recently able to build a comprehensive evolutionary tree of beetles, including data on 57 fossils to contain the timescale of their evolution.
The findings suggest that different beetle clades diversified independently, as various new ecological opportunities emerged.
“There was not a single epoch of beetle radiation, their secret seems to lie in their remarkable flexibility,” explained study lead author Dr. Chenyang Cai, a research fellow in Earth Sciences at Bristol. “The refined timescale of beetle evolution will be an invaluable tool for investigating the evolutionary basis of the beetle’s success story.”
The updated classification of beetles, reflecting the latest genetic and morphological findings, recognizes 193 living and extinct families. The oldest fossils were found to date back to around 295 million years ago, long before the first dinosaurs appeared.
“Reconstructing what happened in the last 300 million years is key to understanding what gave us the immense diversity beetles are known for today,” said Dr. Cai.
According to study co-author Erik Tihelka, a paleo entomologist at Bristol, “because evolution leaves its signature in all aspects of biological organization, our best option is to draw on as many lines of evidence as we can find and see where the threads coalesce. In our case, we have focused on the molecular genetics of living beetles, their morphology, and rare beetle fossils to draw up an updated understanding of their evolutionary history.”
The scientists concluded that beetles first roamed the world in the Carboniferous period and later diversified alongside the earliest dinosaurs during the Triassic and the Jurassic, becoming “the single best case-study in biodiversity that nature gave us,” as Dr. Cai put it.
The study is published in the journal Royal Society Open Science.