When food runs low, even a tight-knit ant colony can turn to desperate measures.
Worker ants in invasive fire ant colonies selectively eat many of their young virgin queens during periods of starvation, using targeted vibrations to mark and coordinate the attacks, researchers report December 15 in Current Biology. This behavior helps the colony conserve resources by sacrificing future reproductives that are not yet essential.
“Our study demonstrates that workers cannibalize a high proportion of virgin queens in food-deprived colonies,” Zheng Yan and colleagues note in the paper.
Cannibalism is not unheard of in ant societies, especially under stress. Past studies have shown that workers may consume eggs or larvae when resources are scarce to keep the rest of the colony alive. But focusing on virgin queens (winged females that have emerged as adults but not yet mated or left the nest) adds a new layer to how ants make tough survival choices.
Yan and colleagues uncovered this while studying how the fire ant Solenopsis invicta, a notorious invasive species, handles food shortages. They divided colonies into groups, depriving some of food while feeding others normally. In the starved groups, about 30 percent of virgin queens died within 10 days, compared to none in the fed groups. Isolated starved queens survived just fine on their own, pointing to the workers as the cause.
Closer looks revealed clear signs of cannibalism. Workers surrounded certain queens, drained their bodily fluids, and consumed soft tissues, leaving lighter, damaged remains often discarded in waste areas. No such damage appeared on queens that died naturally.
The key trigger turned out to be a specific type of vibration, called stridulation, that workers produce by rubbing parts of their abdomens together. In starved colonies, workers directed these signals right onto the bodies of selected queens, drawing more ants to gather and attack. The vibrations differed from those used in distress situations, like when an ant is trapped and needs rescue — they had a lower frequency, a narrower range, and a softer intensity.
“This behavior is triggered by nutritional stress and mediated by a specific vibrational signal (stridulation) produced by workers and directed at young queens selected for elimination,” researchers write.
To confirm the role of these signals, the team played back recordings of the on-queen vibrations to virgin queens in starved colonies using tiny wires to transmit the shakes. This prompted workers to cannibalize the targeted queens at much higher rates than controls or when distress vibrations were played. Chemical profiles on the queens’ surfaces showed no differences between those attacked and those spared, suggesting the vibrations alone drive the response.
“These findings uncover a previously unrecognized role for stridulation in regulating social behavior and challenge the notion that non-chemical communication is secondary in ants,” the study notes.
Citations
Z. Yan et al. Targeted cannibalism of queens mediated by worker signals in fire ants. Current Biology. Published online December 15, 2025. DOI: 10.1016/j.cub.2025.10.044
