Ant cloning just moved from a theoretical curiosity to a field‑verified strategy: a Messor ibericus queen can generate offspring spanning two species and hybrid workers, a reproductive twist newly documented in Nature. [1] Biologists called the rule‑breaking setup “almost impossible to imagine,” after genomic sleuthing showed males of another species emerging from her eggs. [5] Science.org’s report on 4–5 September 2025 underscores how this discovery forces a rethink of what defines a species and a colony. [2]

In a population‑genomic survey of 390 ants across the Messor genus, researchers identified 164 hybrids—about 42%—carrying M. ibericus mitochondrial DNA paired with M. structor nuclear genomes. [2] The team proposes “xenoparity” for this obligate cross‑species cloning, where stored sperm is used to clone foreign male genomes even as queens still produce their own queens and males. [1]

Key Takeaways

– Shows 164 of 390 sampled ants (42.1%) were hybrids, carrying M. ibericus mitochondria with M. structor nuclear DNA across multiple populations. [2] – Reveals queens make four offspring types: M. ibericus queens, M. ibericus males, cloned M. structor males, and hybrid workers via cross-species clonal reproduction. [1] – Demonstrates hybrids present over 1,000 km beyond M. structor’s range, and species diverged more than 5 million years, challenging classic species boundaries. [3] – Indicates lab isolations still produced first-generation hybrids, implying stored sperm enables male genome cloning without contemporary M. structor present in colonies. [4] – Suggests long-term clonal maintenance of foreign M. structor male lineages within M. ibericus colonies, facilitating worker production and potential range expansion. [1]

Ant cloning in Messor ants: four offspring routes

Nature’s study of Messor ibericus reports a single queen producing four distinct offspring types: M. ibericus queens, M. ibericus males, M. structor males cloned from stored sperm, and hybrid workers that blend parental genomes. [1] This is not occasional hybridization; it is a structured, repeatable pattern that reorganizes reproductive roles within the colony. [1]

Field observers and lab notes add a vivid detail: the two male types look different, with “hairy” M. ibericus males and “bald” M. structor males; yet both male types share the queen’s M. ibericus mitochondria. [5] That mitochondrial signature confirms the eggs are laid by M. ibericus queens even when the nuclear genome in some male offspring is cloned from the other species. [5]

Mechanistically, researchers infer that stored M. structor sperm provides a complete nuclear template to produce males of that species and hybrid workers, while queens still generate M. ibericus queens and males through their own genetic pathways. [1] This obligate cross‑species cloning allows the colony to assemble a workforce and reproductive castes from two species without live M. structor males on site. [2]

Genomic evidence: 390 ants, 164 hybrids, and clonal males

Population‑genomic analyses spanned 390 individual ants from five species in the Messor genus, delivering a dataset robust enough to quantify unusual reproductive outcomes with confidence. [4] Within that sample, the team documented 164 hybrids with mixed genomic ancestry, an approximate 42% hybridization rate across the survey’s focal populations. [2]

Genotyping showed hybrid workers consistently carried M. ibericus mitochondrial DNA—reflecting the maternal origin of eggs—but their nuclear genomes tracked M. structor, demonstrating a cross‑species genomic mosaic. [2] Researchers also uncovered clonal M. structor nuclear lineages persisting within M. ibericus colonies, evidence that foreign male genetic lines can be maintained long‑term in a different species’ social structure. [4] This persistence aligns with the authors’ suggestion that foreign male lineages are clonally maintained over evolutionary timescales. [1]

Taken together, these results quantify a colony system in which multiple reproductive channels operate simultaneously: conspecific queens and males, cloned heterospecific males, and mixed‑genome workers. [1] The composite workforce and reproductive castes are not random accidents but repeatable outcomes detected across hundreds of individuals and multiple populations. [4]

How ant cloning challenges species boundaries and range maps

One of the starkest signals came from geography: hybrids were recorded more than 1,000 km from any known M. structor populations, including observations in Sicily, undermining the notion that this system requires ongoing heterospecific contact. [3] The distance makes sense if stored M. structor sperm is being used to clone a foreign male genome and produce hybrid workers far from potential M. structor mates. [5]

Compounding the surprise, M. ibericus and M. structor have diverged for more than 5 million years, yet they are functionally integrated within the same colony’s life cycle through xenoparity. [3] As senior author Jonathan Romiguier noted, queens can clone M. structor males from stored sperm to secure worker production even where M. structor is absent, stretching traditional species definitions. [2]

What ‘xenoparity’ means and why it matters

The authors coin “xenoparity” to describe obligate cross‑species cloning that produces viable offspring beyond standard hybridization, combining maternal mitochondria with a foreign nuclear genome for specific castes. [1] Xenoparity formalizes an arrangement in which foreign genetic lineages are not only tolerated but integrated as stable, colony‑level assets. [1]

By naming and documenting xenoparity, the study reframes reproductive strategy as a colony‑level optimization problem rather than a single‑species gene flow event, linking sperm parasitism and obligate cross‑species cloning to ecological performance, such as range expansion. [4] It transforms a puzzling set of genotypes into a coherent life‑history strategy with testable evolutionary predictions. [4]

Mechanisms remain elusive; lab tests rule out cohabiting males

Despite the detailed genomic picture, the cellular mechanism that turns stored sperm into cloned males of another species—and hybrid workers with mixed genomes—remains unknown. [1] Key questions include how the foreign nuclear genome is retained or excluded during development and how the system avoids genetic incompatibilities across species boundaries. [1]

Crucially, when M. ibericus queens were kept in isolation, they still produced first‑generation hybrids, a result that argues strongly against hidden or cohabiting M. structor males as the source of the foreign genome. [4] That finding isolates stored sperm as the most parsimonious driver of the observed cross‑species cloning. [4]

A working model posits that queens deploy stored M. structor sperm in a clonally biased way: complete foreign nuclear genomes for male offspring and a hybrid nuclear complement for workers, all atop maternal mitochondria. [2] The male caste’s split appearance—“hairy” M. ibericus versus “bald” M. structor—mirrors this genomic partitioning and provides an external cue to the underlying genetic asymmetry. [5]

Ant cloning and the colony calculus: payoffs and risks

Functionally, xenoparity looks like a colony‑level insurance policy: by cloning foreign males and producing hybrid workers, M. ibericus colonies can sustain labor and reproduction even in landscapes missing one parental species. [2] The strategy can decouple colony success from local partner availability, a major advantage in sparse or shifting habitats. [2]

Authors discussing an evolutionary path from sperm parasitism to obligate cross‑species cloning suggest this system could facilitate geographic spread, consistent with hybrids turning up >1,000 km from known M. structor ranges. [4] If colonies can bootstrap worker production through stored foreign genomes, they gain a demographic foothold well beyond typical hybrid zones. [3]

There are, however, unknowns that matter: how reliably stored sperm endures, whether clonal male lineages accumulate deleterious mutations, and how conflicts between genomes are managed over time. [1] The Nature team’s finding that foreign male lineages are clonally maintained inside M. ibericus colonies hints at a long‑term evolutionary accommodation rather than a short‑lived anomaly. [1]

Ant cloning’s next tests: mapping, mechanisms, and models

Two priorities stand out. First, nail down the developmental mechanism—how embryos partition nuclear genomes to yield foreign males and hybrid workers while preserving maternal mitochondria. [1] Second, map where xenoparity is operating now, given the >1,000 km decoupling between hybrid occurrence and M. structor’s known range. [3]

The study, funded by the European Research Council, has already catalyzed cross‑disciplinary interest because it challenges speciation dogma with hard numbers and replicable patterns. [1] With Science.org, El País, and Phys.org covering the work on 4–5 September 2025, the next wave will likely blend field sampling, controlled crosses, and fine‑scale genomics to test how widespread this rule‑breaking reproductive strategy really is. [2]

Sources: [1] Nature – One mother for two species via obligate cross‑species cloning in ants: https://doi.org/10.1038/s41586-025-09425-w [2] Science.org – Ant queen breaks the rules by producing male offspring that are a different species: www.science.org/content/article/ant” target=”_blank” rel=”nofollow noopener noreferrer”>https://www.science.org/content/article/ant [3] El País (English) – ‘Messor ibericus’: The ant that lays eggs of two different species: https://english.elpais.com/science-tech/2025-09-04/messor-ibericus-the-ant-that-lays-eggs-of-two-different-species.html [4] Phys.org – Iberian harvester ant queens are cloning different species to produce hybrid workers: https://phys.org/news/2025-09-iberian-harvester-ant-queens-cloning.html [5] ZME Science – Ant queen produces offspring of two species — ‘almost impossible to imagine’: www.zmescience.com/science/news-science/ant-queen-breaks-the-rules-of-biology-by-producing-male-offspring-that-are-a-different-species/” target=”_blank” rel=”nofollow noopener noreferrer”>https://www.zmescience.com/science/news-science/ant-queen-breaks-the-rules-of-biology-by-producing-male-offspring-that-are-a-different-species/

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