Research published today in the journal Science Advances shows that part of the answer lies in a subtle but consequential shift in how individual workers are built.
Using a computer vision approach applied to 3D X-ray scans, researchers digitally reconstructed the anatomy of more than 500 ant species and traced how their investment in the cuticle, the external exoskeleton that provides protection but is costly to produce, evolved over time.
They found that ants expanded their colonies not by shrinking their workers, but by reducing investment in their armour. This shift toward thinner cuticles allowed colonies to produce more workers at lower cost, facilitating the rise of larger and more complex societies.
Beyond enabling larger colonies, species with reduced cuticle investment also diversified faster over evolutionary time. In contrast, neither colony size nor worker body size alone predicted diversification, pointing to reduced worker cost as a key component of ant evolutionary success.
Lead author Arthur Matte, a PhD student in Zoology, said, “This evolutionary shift, toward cheaper yet more numerous workers, paved the way for the explosive rise of ant societies that are now found across nearly all terrestrial ecosystems.
“The trade-off between quantity and quality is all around. It’s in the food you eat, the books you read, the offspring you want to raise. It was fascinating to retrace how ants handled it through their long evolution. We could see lineages taking different directions, shaped by different constraints and environments, and ultimately giving rise to the extraordinary diversity we observe today.”
Arthur Matte’s research story
Arthur told us about the background to his research, "I’m fascinated by the stories evolution leaves behind, and how tracing them helps us understand the living world today. My work focuses on reconstructing those stories, using data from many species and phylogenetic comparative methods.
"I carried out this study during my Master’s degree at the Okinawa Institute of Science and Technology (OIST) in Japan, where I explored how ants evolved cheaper workers to build larger societies. It followed naturally from an earlier project with Dr. Adria LeBoeuf, where we examined how ants evolved distinct queens and workers to forge their social complexity (PNAS, 2025).
"I’m now pursuing my PhD with Dr Adria LeBoeuf at the University of Cambridge, extending these evolutionary approaches to the molecular level using omic data to understand how complex systems such as sperm first came to be, and what this can teach us (bioRxiv, 2025)."
Read the paper: Arthur Matte, Benoit Guénard, Shubham Gautam, Fumika Azuma, Julian Katzke Francisco Hita Garcia, Thomas van de Kamp, and Evan P. Economo ,'The evolution of cheaper workers facilitated larger societies and accelerated diversification in ants'.Sci. Adv.11,eadx8068(2025). DOI:10.1126/sciadv.adx8068
Image: 3D reconstruction of the exoskeleton of an ant worker (Myrmoteras sp.) from x-ray tomography. Credit: Julian Katzke