Large-scale distribution of hybridogenetic lineages in a Spanish desert ant.

Recently, a unique case of hybridogenesis at a social level was reported in local populations of the desert ants Cataglyphis. Queens mate with males originating from a different genetic lineage than their own to produce hybrid workers, but they use parthenogenesis for the production of reproductive offspring (males and females). As a result, non-reproductive workers are all inter-lineage hybrids, whereas the sexual line is purely maternal. Here, we show that this unorthodox reproductive system occurs in all populations of the ant Cataglyphis hispanica. Remarkably, workers are hybrids of the same two genetic lineages along a 400 km transect crossing the whole distribution range of the species. These results indicate that social hybridogenesis in C. hispanica allows their maintenance over time and across a large geographical scale of two highly divergent genetic lineages, despite their constant hybridization. The widespread distribution of social hybridogenesis in C. hispanica supports that this reproductive strategy has been evolutionarily conserved over a long period.