Researchers documented how parasitic queens of Lasius ants chemically manipulate host workers to attack and kill their own queen, then take over the colony. Invaders first acquire the colony scent to enter undetected, then spray an abdominal fluid smelling of formic acid that agitates workers. In experiments, workers mutilated the resident queen within four days, after which the parasite began laying hundreds of eggs and eventually replaced the colony lineage. The study, published in Current Biology, reveals a previously undocumented form of social parasitism driven by chemical deception.
Scientists Reveal How Parasitic Ant Queens Trick Workers Into Killing Their Own Queen
Researchers documented how parasitic queens of Lasius ants chemically manipulate host workers to attack and kill their own queen, then take over the colony. Invaders first acquire the colony scent to enter undetected, then spray an abdominal fluid smelling of formic acid that agitates workers. In experiments, workers mutilated the resident queen within four days, after which the parasite began laying hundreds of eggs and eventually replaced the colony lineage. The study, published in Current Biology, reveals a previously undocumented form of social parasitism driven by chemical deception.
05:51 AM, 11/18/2025Science
Parasitic ant queens use chemical deception to seize colony control
Researchers report they have, for the first time, revealed the mechanism by which a parasitic ant queen chemically manipulates host workers into attacking and killing their colony’s legitimate queen — allowing the invader to take over and become the new reproductive center. The findings were published in the journal Current Biology.
The study focused on ants in the genus Lasius, documenting invasions and worker manipulation by parasitic queens of L. orientalis and L. umbratus in several host species. Coauthors Taku Shimada and Yuji Tanaka — both citizen scientists in Tokyo — raised host colonies and introduced parasitic queens to observe the takeover process under controlled conditions.
How the takeover unfolds
Ants rely heavily on smell to recognize nestmates. To gain initial acceptance, the invading queen first acquires the colony odor by cohabiting with host workers and cocoons. Once she can enter the nest without immediate aggression, she moves to the colony’s feeding area, where most workers either ignore her or even feed her mouth-to-mouth.
That apparent calm is deceptive. After locating the resident queen, the parasite sprays an abdominal fluid that smells of formic acid. This chemical signal agitates the workers and provokes aggressive responses: some workers immediately attack their own queen. The intruder repeats the spraying and the assaults intensify over several days. In the experiments reported, "the host workers eventually mutilated their true mother after four days," the authors wrote.
“Inducement of daughters to kill their biological mother had not been known in biology before this work,”
said study senior author Dr. Keizo Takasuka, an assistant professor in the department of biology at Kyushu University, in an email to CNN.
Aftermath and ecological context
With the resident queen dead, the parasitic queen begins laying hundreds of eggs, tended by the adopted host workers. Over time, her offspring can number in the thousands and effectively replace the original colony lineage.
Experts say the result reveals a striking and previously undocumented form of social parasitism. Dr. Jessica Purcell, a professor of entomology at the University of California, Riverside, called the discovery "astonishing," particularly because the parasite elicits violent behavior from workers using a chemical cue rather than direct combat.
Social insects that store communal resources are attractive targets for parasites. Some species raid and enslave brood; others infiltrate nests and usurp reproductive roles. This study documents a novel tactic: using chemical deception to turn workers into instruments of matricide, enabling the intruder to inherit an intact labor force.
Broader significance
Beyond ant biology, the results highlight how chemical communication can be hijacked to disrupt social systems. As Takasuka observed, such natural phenomena can sometimes exceed scenarios imagined in fiction.
Study citation: Takasuka et al., Current Biology (publication details in the original article).