MATRICIDE BY MISINFORMATION
- Mar 27
- 3 min read
Updated: Mar 31
Parasitism has to be one of the most interesting aspects of biology. You may have come across the better known fungal, worm, or single-celled protist parasites who control the minds of their host for their own purposes. Lesser known are the parasitoid wasps. But with them, if you don't know, you can mostly erase from your mind what you think of when you think of "wasp". Many of these are no bigger than a grain of sand and others are only about the size of a sesame seed. They tend to operate by stealth and are almost never seen by humans never mind found stinging you or trying to eat some part of your picnic. They also perform critical pest control functions. Biologists estimate there are up to a million species of these specialist wasp species. As such, it's very likely that if you're looking at an insect or spider there's a some species of wasp who has figured out how to exploit that or a similar species to said wasp's reproductive ends. Wasps are so good at this activity that you can even find what are called hyperparasitoid wasps. Those have evolved to parasitize other parasitoid wasps, where one wasp uses as a host for its eggs the body of another parasitoid wasp that is already living inside another host species (probably a caterpillar or beetle). ZOINKS! But we're here to talk about a pair of newly discovered parasitoid ants that are just as weird/wonderful and deploy a whole different strategy.
Ants experience the world through chemistry. An ant's exoskeleton is covered in a waxy, aromatic layer of cuticular hydrocarbons that act as a "biochemical uniform" revealing an individual ant's colony, status, and work to other ants. They also "talk" in chemistry with glands producing specialized pheromones to convey highly specialized messages for other ants. For example, a forager will deposit pheromones on the ground to map a route to food or one will drop alarm pheromones when a threat is perceived. And an ant's antennae act like a dog's nose, allowing them to figure out the direction and intensity of these pheromones and follow these chemical trails and in this way "see" their way through the world.
Though this chemical signaling is extremely precise and effective, and ants remarkably good at sending and receiving chemical code, this simple mode can be be easily highjacked. Two ant enthusiasts in Japan recently discovered some examples of ant parasitism never seen before in which queens from a pair of ant species in the genus Lasius were found infiltrating and commandeering the colonies of other Lasius species.
Lasius orientalis is a Japanese temporary social parasite ant. When new queens emerge from the colony those newly impregnated females penetrate Lasius flavus colonies by loitering in proximity to their workers in order to obtain that colony's scent. Once camouflaged in friendly pheromones, the invading queen is able to walk among the colony and hunt down the colony's queen without raising alarm. When the host queen is found a chemical attack ensues. The invader sprays the queen with a liquid believed to be formic acid.
Formic acid is the simplest carboxylic acid. It appears as a colorless but pungent liquid and is deployed throughout the plant and animal worlds, serving as a defensive chemical and antimicrobial agent in organisms such as ants, beetles, stingless bees, and stinging nettles. Interestingly too, more than 200 species of birds (including jays, robins, thrushes, starlings, and more) deliberately antagonize ants they know to spray formic acid in a behaviour known as "anting" — the non-human version of hitting up your pharmacist. The birds coax the ants to deploy their stinky antimicrobial to help them rid their feathers and bodies of insect and fungal parasites. Genius...
The invader slinks away while the colony is led to believe their queen, dosed in potent and offensive perfume, is an alien threat. With no immunity, antidote, nor any form of counterattack the queen is quickly killed and torn apart by her colony, her own daughters. Post-matricide, her counterpart, the parasitic queen, takes her throne, as it were, and has the dead queen's daughters feed her and care for her own larvae.
Terrible and amazing.
This behavior was first captured on video by amateur ant enthusiast Taku Shimada and subsequently documented in a scientific publication by researchers from Kyushu University, and demonstrating a novel application for formic acid and a new chemical warfare strategy.
FOR MORE CHECK OUT:
Shimada, Tanaka, & Takasuka; 2025 - Socially parasitic ant queens
chemically induce queen-matricide in host workers
Kuroba, 2025 - Silent Invasion: How Parasitic Queens Make Ants Kill Their Mother
