From Independent Feeders to Spoon-Fed: How larval care shaped ant societies

What is it about?

Most ant colonies are superorganisms where queens focus on reproduction while workers handle everything else—but the size difference between queens and workers varies dramatically across ant species. This study reveals that evolutionary shifts in larval feeding unlocked extreme caste specialization and social complexity in ants. By analyzing larval morphology in over 700 species and measuring queen-worker size differences in nearly 400 species, we discovered that ancestral ant larvae were autonomous feeders with elongated necks and toothed mandibles that could chew through prey items. As ant lineages shifted away from purely predatory diets, larvae evolved passive morphologies—losing their necks and teeth—as adults began individually feeding them processed foods like liquids, eggs, and prepared pellets. This transition gave adult workers unprecedented control over larval nutrition, effectively resolving a fundamental conflict: larvae naturally "want" to become queens by consuming as much food as possible, but colonies benefit from producing mostly workers. Enhanced parental control enabled colonies to reliably channel larvae into specialized castes, resulting in larger colony sizes, worker subcastes, and reduced worker reproduction—the hallmarks of advanced ant societies that dominate ecosystems worldwide.

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Photo by Dibakar Roy on Unsplash

Photo by Dibakar Roy on Unsplash

Why is it important?

This research identifies a critical evolutionary innovation that transformed ants from simple societies into the ecological powerhouses that now constitute a significant portion of terrestrial animal biomass. Adult control over larval development was both a cause and consequence of increased social complexity—a key insight into how major evolutionary transitions occur when individual interests must be subordinated to collective function. The work has implications beyond ants. Just as multicellular organisms required cells to relinquish autonomy, superorganisms like ant colonies required individuals to surrender developmental control. By demonstrating that dietary shifts created opportunities for adults to override larval self-interest, the study shows how cooperation evolves despite inherent conflicts—a fundamental challenge in systems ranging from cellular communities to human societies. Understanding these mechanisms helps explain not just how ants became dominant ecosystem engineers, but how any complex cooperative system can emerge from competing individual interests.