Parasitic ant queens infiltrate rival colonies, chemically manipulate worker ants into killing their own mother, and then assume control of the nest, according to a new study published in Current Biology. The invading queens use formic acid to erase the host queen’s scent, triggering a violent attack by the workers, who dismember and kill their own mother.
The Deceptive Takeover
Certain ant species, like Lasius orientalis and Lasius umbratus, are social parasites. Rather than building their own colonies, they invade those of other species, such as Lasius flavus and Lasius japonicus, taking over and enslaving the workers. Scientists previously knew these invaders mimic the host colony’s scent to avoid detection, exploiting the ants’ reliance on chemical cues in the dark nest.
The new research reveals how the takeover is completed: the invading queen sprays the host queen with formic acid, effectively erasing her unique scent. This chemical manipulation turns the workers against their own mother, triggering a brutal attack. The queen is dismembered and killed by her own daughters, after which the invader lays her own eggs, and the workers raise her offspring.
Chemical Warfare and Scent Erasure
The study, led by Keizo Takasuka at Kyushu University, involved laboratory experiments where invading queens were introduced into host nests. The results showed that the formic acid spray reliably triggered the attack. This chemical warfare is particularly effective because ants rely heavily on scent for recognition. By eliminating the host queen’s signature odor, the invader effectively frames her as an intruder.
Daniel Kronauer, a researcher at Rockefeller University, explains that ants often use formic acid as an alarm signal when threatened. The parasitic queen repurposes this defense mechanism to manipulate the workers. By spraying the host queen, she effectively broadcasts a false alarm, convincing the colony that their mother is an enemy.
A Manipulative Strategy
Once the host queen is eliminated, the parasitic queen blends into the colony’s scent profile. The workers treat her as one of their own, raising her offspring without suspicion. Over time, the original workers die out, replaced by the invader’s brood. The parasite queen has successfully hijacked the colony, ensuring the survival of her own lineage.
This behavior is unique in the ant world. Matricide, or killing one’s mother, is rare in nature, usually occurring for the benefit of the species. In this case, however, only the parasite species benefits. The workers act on a manipulated signal, committing an act that is ultimately detrimental to their own survival.
The parasitic queen’s strategy is a stark example of manipulative behavior in the natural world. By exploiting the ants’ reliance on scent and repurposing their own defense mechanisms, she ensures the survival of her lineage at the expense of the host colony
