Coevolution
Antagonistic coevolution

Antagonistic coevolution is seen in the harvester ant species Pogonomyrmex barbatus and Pogonomyrmex rugosus, in a relationship both parasitic and mutualistic. The queens are unable to produce worker ants by mating with their own species. Only by crossbreeding can they produce workers. The winged females act as parasites for the males of the other species as their sperm will only produce sterile hybrids. But because the colonies are fully dependent on these hybrids to survive, it is also mutualistic. While there is no genetic exchange between the species, they are unable to evolve in a direction where they become too genetically different as this would make crossbreeding impossible.
language:response_language[German], detectable_format:number_bullet_lists[7], length_constraints:number_sentences[13]