Queen ants in southern Europe have revealed a surprising twist in reproductive biology. In some colonies of the Iberian harvester ant (Messor ibericus), queens create male clones of a different species, Messor structor. This unusual method challenges our traditional understanding of species and reproduction.
The workers in these colonies are hybrids. Queens typically mate with M. structor males to sustain their colonies. Surprisingly, researchers found areas where isolated M. ibericus populations thrive without M. structor nearby. This finding baffled evolutionary biologist Jonathan Romiguier from the University of Montpellier. Initially, he thought there was a sampling error, but further investigation showed this was a widespread phenomenon.
In a groundbreaking study published in Nature, Romiguier’s team discovered that queen M. ibericus also produces male M. structor offspring. This means they can incorporate genetic material from another species into their colonies, something not previously documented in animals. “At first, we thought it was a joke within the team,” Romiguier said, but the more data they collected, the more serious it became.
The concept of ants as eusocial insects means their groups function like super-organisms. Usually, males exist solely to mate with queens and die shortly after mating. Queens typically store sperm to produce different types of offspring: queens, workers, or males. However, M. ibericus queens can only produce new queens if they mate with their own kind. That’s why the isolated colonies posed such a mystery.
Romiguier’s team sampled 132 males across 26 colonies. They found that male M. ibericus had distinctive hairy bodies, unlike the hairless M. structor. DNA analysis confirmed that all the male M. structor were born from the same queens as the M. ibericus. This finding led the researchers to a startling conclusion: M. ibericus queens were cloning M. structor males without contributing any of their own genetic material.
The team also monitored 16 queens, discovering that about 9% of their eggs were male M. structor. They observed a single queen consistently producing both species over 18 months. This phenomenon is so unique that Romiguier calls it “xenoparity,” signifying the birth of another species.
Denis Fournier, an evolutionary biologist not part of the study, expressed awe at the revelation, describing it as almost science fiction. He emphasized that such findings remind us to be open to unexpected possibilities in nature. “Now, old puzzling data might suddenly make sense,” he noted.
Recent studies show that cross-species reproduction could offer insights into broader biological concepts. For instance, a study in Nature Ecology & Evolution recently found that similar adaptive strategies exist among various species, highlighting a theme of flexibility and resilience in nature.
In a world focused on strict species boundaries, this new understanding invites us to rethink our perspectives on evolution, cooperation, and the unexpected intricacies of life. Researchers are now eager to explore the mechanisms of this cloning process and its implications for our knowledge of species evolution.
For additional reading on the complexities of ant reproduction and species interaction, check out the National History Museum and Genome.gov.
