Large-scale genomic research on darkling beetles, a group of over 30,000 species that is incredibly diverse across the globe, sheds light on a 150-million-year evolutionary story of this crucial yet often overlooked part of Earth’s ecosystem, as revealed by new findings from The Australian National University (ANU) and CSIRO.
Large-scale genomic research on darkling beetles, a group of over 30,000 species that is incredibly diverse across the globe, sheds light on a 150-million-year evolutionary story of this crucial yet often overlooked part of Earth’s ecosystem, as revealed by new findings from The Australian National University (ANU) and CSIRO.
Researchers have been fascinated by the remarkable diversity of darkling beetles—small insects that have been around since the time of the dinosaurs—and their remarkable ability to adapt and flourish in various challenging environments over millions of years.
However, the mechanisms behind their evolution and the traits that enabled them to thrive globally were largely unknown until now.
Dr. Yun (Living) Li, the lead author from ANU and CSIRO, stated that darkling beetles experienced several major evolutionary events early on, which equipped them to expand into numerous terrestrial habitats and rapidly develop the diverse array of body shapes seen today.
“Darkling beetles mainly act as scavengers and serve important functions as decomposers in ecosystems. Their behaviors, however, are varied,” Dr. Li noted.
“These beetles excel in adapting their body shapes, showcasing a variety of forms from cylindrical wood-boring shapes resembling candlesticks to rounded, surface-grazing forms like ping-pong balls.”
Through DNA analysis from beetle specimens in museums, the team was able to reconstruct an evolutionary tree, tracing back the development of over 300 species over 150 million years.
To explore the factors behind the variety in darkling beetle species, the researchers gathered ecological data and examined body shape differences by converting more than 900 specimens housed at the Australian National Insect Collection (ANIC) at CSIRO into digital formats.
The findings showed significant differences in the pace of body shape evolution across the darkling beetle lineage, with some branches evolving particularly quickly—a phenomenon the researchers termed “quantum evolution.”
This rapid evolutionary capability enabled darkling beetles to quickly adapt their shapes to meet the challenges posed by new environments.
Dr. Li remarked that quantum evolution is crucial for the exceptional “shape-shifting” abilities observed in darkling beetles.
“This adaptability has allowed darkling beetles to thrive in diverse environments that have transformed over millions of years, from tropical savannas to dry deserts, coastal dunes, mountain tops, and even in our own backyards,” Dr. Li explained.
“Our findings indicate that quantum evolution was a common occurrence throughout the evolutionary lineage of darkling beetles. We identified over 60 rapid evolutionary changes connected to shifts in the specialized habitats these beetles occupied.”
Historically, these beetles experienced several periods of quick evolutionary changes, particularly around the time of the Cretaceous-Paleogene mass extinction event approximately 66 million years ago, which eradicated over 70% of Earth’s species.
With more than 400,000 identified species, beetles represent nearly a quarter of all animal life on the planet. Dr. Li emphasized that these insects “truly dominate the world” in terms of their vast diversity and ecological roles.
“By exploring the evolutionary pathways of these small yet enormously diverse insects, we gain valuable insights into the evolution of diverse life on Earth,” Dr. Li said.
“The swift evolution of darkling beetles has positioned them as leaders in global ecology.”
This research has been published in Current Biology.
