These Ant Queens Seem to Defy Biology: They Lay Eggs That Hatch Into Another Species By Sarah Kuta — September 8, 2025 --- Overview Iberian harvester ant queens (Messor ibericus) possess a remarkable and unique reproductive ability — they lay eggs that can hatch into two different species. This discovery challenges established biological concepts about species and reproduction and was detailed in a September 3, 2025, paper published in Nature. --- Key Findings Dual-species offspring: M. ibericus queens mate with males of another species, the builder harvester ant (Messor structor), and lay eggs that hatch into males of both species. Xenoparity coined: Researchers named this reproductive phenomenon "xenoparity," meaning "foreign birth," where one mother produces offspring of a different species. Genetic mechanism: Queens store M. structor sperm and fertilize some eggs with it. They remove their own genetic material from those eggs, producing effectively M. structor male clones. Colony structure: M. ibericus colonies contain female hybrid workers (mix of both species). Queens produce M. ibericus males that mate with queens to produce new M. ibericus queens. Queens clone M. structor males, aiding the preservation and spread of M. structor males for future matings. Evolutionary surprise: The two species diverged over five million years ago, a substantial evolutionary distance comparable to humans and chimpanzees. --- Research Challenges Locating males was difficult because in a 10,000-ant colony, males are scarce. Scientists gathered 132 males from 26 colonies near Lyon, France; about half were nearly hairless (a M. structor trait), confirmed by DNA. All males, even M. structor clones, had M. ibericus mitochondrial DNA (maternal inheritance), proving they originated from M. ibericus queens. Lab attempts to observe births took two years due to difficulties in breeding males in captivity, eventually succeeding. --- Biological and Ecological Implications The arrangement benefits both species, ensuring M. ibericus has sufficient workers and transporting M. structor males to new areas. M. structor colonies are limited to mountainous regions, but M. ibericus queens spread cloned males beyond these habitats. The reproductive strategy challenges traditional biological species definitions. Cloning of M. structor males could lead to accumulation of harmful mutations over time, potentially threatening long-term viability. --- Expert Commentary Xim Cerdá (ecologist) highlights the need to rethink the concept of species. Jacobus Boomsma (evolutionary biologist) calls it a "fantastic, bizarre system." Sara Helms Cahan (evolutionary ecologist) admires the reproductive "tricks" employed, describing the partnership as "fantastical but incredibly successful." --- Visuals and Media Images show the two brothers of different species and the queen ants. A video titled "'How is this possible?' - two species birthed by one mother" is available on YouTube. --- Additional Information Scientists estimate 20 quadrillion ants inhabit Earth. Related topics include ant genetics, biology, reproduction, and wildlife. --- Summary This research reveals an extraordinary reproductive system where a single ant queen produces offspring of two species by effectively cloning males from another species. This finding challenges classical species definitions, contributes insight into coevolution, and reflects complex reproductive strategies in ants. It may reshape biological understanding of species interactions and inheritance. --- For more stories, explore related articles on ant DNA, queen longevity, and insect biodiversity featured on Smithsonian Magazine.