Florida Harvester Ant – Pogonomyrmex badius, Lake June-in-Winter Scrub State Park, Lake Placid, Florida. Credit: Judy Gallagher – CC BY 2.0 via Wikimedia Commons.
Researchers reported that a queen ant in southern Europe has become the first known animal to consistently produce offspring of different species, a finding that questions basic assumptions about reproduction and species boundaries.
Scientists studying the Iberian harvester ant, Messor ibericus, found that queens not only sire sons of their own species but also lay eggs that develop into males of a distantly related species, Messor structor. The startling result, first documented Sept. 3 in the journal Nature, shows queens cloning males of another species as part of their normal life cycle, researchers said.
“That was very, very abnormal. I mean, it was kind of a paradox,” said study co-author Jonathan Romiguier, an evolutionary biologist at the University of Montpellier, describing early puzzlement when field surveys turned up thriving M. ibericus colonies with no nearby M. structor populations. “In the early stages, it was kind of a joke in the team. But the more we got results, the more it became a hypothesis and not a joke anymore.”
The ant became the first known animal to produce offspring from an entirely different species
In most ant societies, queens mate once, store sperm, and use it to produce workers and future queens, while males exist mainly to fertilize queens and then die. In M. ibericus colonies, workers are hybrids produced when queens mate with M. structor males.
Queens that mate only with males of their own species tend to produce mostly queens, a bias thought to stem from so-called “royal cheater” genes. That reliance on M. structor males to produce workers made the isolated M. ibericus colonies a complete mystery to the researchers.
Ant Queen Gives Birth to Two Different Species
Researchers uncover an unusual survival strategy in Iberian harvester ants that turns basic biology on its head.#ant #species #iberian #messor #ibericus #structor #italy #sicily #jettison #jessicapurcell #animal #biology #nature pic.twitter.com/etpb6mkbL2
— Ervan Erfian (@ervanerfian) September 15, 2025
To understand the anomaly, Romiguier’s team sampled 132 male ants from 26 colonies and found 58 hairy males, a number which is typical of M. ibericus, and 74 hairless males that genetically matched M. structor. Crucially, mitochondrial DNA, which is inherited from the mother, showed that the hairless M. structor males carried the same maternal line as their M. ibericus nestmates, indicating the queens themselves produced them.
Lab work showed it was not an anomaly
Laboratory work bolstered the case. Genetic sequencing of freshly laid eggs from 16 captive queens showed approximately 9% contained M. structor males. Researchers also directly observed a single queen producing males of both species over eighteen months.
The research team has coined the term “xenoparity,” which means the birth of a different species, to describe the phenomenon. How queens affect the cloning by apparently producing males that carry M. structor nuclear genomes while retaining maternal mitochondrial DNA remains unclear, Romiguier said. He and colleagues said further work will be needed to find the molecular mechanism and determine how long the system has been in place. The two species diverged between roughly five million years ago and, possibly, only a few thousand years ago.
An ant queen just gave birth to two different species, stunning scientists.
Researchers studying Iberian harvester ants in Europe uncovered one of the strangest reproductive systems in the natural world. A single queen can lay eggs that hatch into two completely different… pic.twitter.com/hiMkz7zoFn
— Massimo (@Rainmaker1973) September 14, 2025
“This is almost like science fiction,” said Denis Fournier, an evolutionary biologist at the Free University of Brussels who was not involved in the study. “It’s jaw-dropping. Most of us learn that species boundaries are firm, yet here is a system where ants regularly cross them as part of normal life.”
Researchers said the discovery raises new questions about cooperation, conflict, and dependency in evolution, suggesting that other unexpected reproductive systems may exist, waiting to be found.
