The trade-off between quality and quantity is a core economic challenge. Recent research by a team of British, American, and Japanese scientists highlights how this principle also applies to biological systems, specifically in the evolutionary progression of ants, one of Earth’s most successful groups of organisms.
Their findings indicate that as ant societies expanded in complexity and population, the ants evolved by making their workers smaller and more cost-effective.
The Cost of Armor
In the insect world, the exoskeleton, or cuticle, is crucial as it serves as a protective shield against predators, pathogens, and dehydration, while also providing a structure for muscle attachment. However, this protection requires significant resources, including nitrogen and rare minerals such as zinc and manganese. While lacking sufficient armor can endanger an individual insect, ants appear to have developed a strategy to mitigate this issue.
“There’s this question in biology about what happens to individuals when the societies they belong to become more complex,” explained Evan Economo, an entomologist at the University of Maryland and co-author of the study. “For instance, individuals might become simpler because tasks necessary for a solitary organism can be managed collectively.”
Economo’s team proposed that in social insects like ants, the metabolic trade-off in cuticle production might prioritize the colony over individuals. In a colony of 10,000 workers, losing a few to predators may be inconsequential, making heavy investments in each worker’s defenses a waste of precious nutrients. To examine this theory, they analyzed whether ant lineages with vast, specialized workforces invest less in individual exoskeletons.
Scanning Superorganisms
The researchers had to conduct a large-scale comparative study on ant anatomy to test this theory. “We worked with scans of ant specimens from species worldwide to capture the global diversity of ants,” Economo noted. The research utilized Antscan, an extensive database containing three-dimensional X-ray microtomography imaging of ants from across the globe.