Sick ant pupae, researchers found, perform a rare act of self-sacrifice by releasing a chemical signal that tells their nestmates to destroy them. The finding matters now because it uncovers a hidden layer of social immunity that mirrors how immune cells in our own bodies remove infected cells before they cause harm.
Fast Facts
Study: New research shows sick ant pupae send chemical signals that trigger workers to remove them.
Why It Matters: This self-sacrifice protects the colony from lethal fungal infections.
Key Mechanism: Infected pupae boost two specific hydrocarbons when workers are present.
Surprising Insight: Queen pupae never signal because their stronger immunity fights off infection.
Published In: Nature Communications, 2025.
The study shows that worker pupae of the invasive garden ant Lasius neglectus actively release a distinctive chemical blend when a fungal infection overwhelms their immune system. Past research suggested infected ants were passively detected by smell, but this new work reveals something far more striking. The pupae themselves broadcast a message that says, in effect, “I cannot be saved.” Queen pupae, however, send no such signal because their stronger immune defenses usually defeat the infection before it becomes fatal.
Researchers proved this signalling behavior through carefully controlled experiments. They exposed pupae to a pathogenic fungus and then monitored changes in their chemical “scent” using high-precision gas chromatography and mass spectrometry. They also labeled worker ants with a carbon isotope to separate chemicals produced by the pupae from those transferred by caretaking adults, ensuring the results were accurate and pupae-specific. When the pupae were both infected and surrounded by workers, two key hydrocarbon chemicals increased sharply, forming a signature scent that workers recognized as a call for elimination.
The discovery matters because it reveals a sophisticated early-warning system inside ant colonies. Instead of waiting for visible illness, ants rely on subtle chemical changes to decide whether a young colony member can still survive infection. Workers remove fatally infected pupae before the fungus becomes contagious, protecting the entire colony from collapse. This targeted approach avoids wasting healthy or recoverable individuals and prevents the spread of a lethal pathogen.
Experts say the work offers a rare look at altruistic behavior encoded in biology. Lead researchers Erika Dawson and Sylvia Cremer note that worker pupae have little personal reproductive value but high value to colony health. That makes self-sacrifice beneficial in evolutionary terms. The tension appears with queen pupae, which never signal for death. Yet this is not selfishness. The study shows queens fight off the infection better, reducing their risk of becoming a threat to the colony.
The finding also fits into a broader scientific picture. Social insects act like “superorganisms,” with colonies functioning similarly to a body made of many individuals. Just as human immune cells detect and remove dangerously infected cells, ant colonies use chemical communication to decide which individuals to save and which to sacrifice. This cross-domain link helps scientists understand how distributed systems, from animal societies to engineered networks—maintain stability under microbial or systemic threats.
Next, the research team plans to test how strong an infection needs to be before queen pupae would ever signal for destruction. They also hope to identify which specific chemical isomers trigger worker behavior, since the study found that subtle shifts in chemical structure, not just quantity, shape the message. Many questions remain about how universal these signals are across insect species and how environmental stress might alter them.
This discovery reveals how even tiny creatures maintain collective health through cooperation, self-assessment, and sacrifice. Understanding these natural systems may help scientists design better disease-control strategies, model resilient networks, and appreciate how life uses simple signals to solve complex survival problems.
Story Source:
Materials provided by Institute of Science and Technology Austria (ISTA). Content may be edited for style and length.
Journal Reference:
Erika H. Dawson, Michaela Hoenigsberger, Niklas Kampleitner, Anna V. Grasse, Lukas Lindorfer, Jennifer Robb, Farnaz Beikzadeh, Florian Strahodinsky, Hanna Leitner, Harikrishnan Rajendran, Thomas Schmitt, Sylvia Cremer. Altruistic disease signalling in ant colonies. Nature Communications, 2025. 16(10511). DOI: 10.1038/s41467-025-66175-z s41467-025-66175-z