Iberian harvester ant queens are cloning totally different species to supply hybrid employees

Worker ants carry out necessary duties like gathering meals, taking good care of eggs and larvae and nest constructing. However, some species of ants can’t produce employees by way of reproductive means with their very own species. Eggs fertilized by male ants of the identical species end result solely in additional queens, whereas unfertilized eggs end in winged males—these which depart the nest to mate with queens. So, the place do the employees come from in these ant species?

Typically, ants incapable of manufacturing employees are identified to mate with different species to be able to produce these essential members of their colony. This leads to hybrid offspring as employees. Of course, this reliance on replica with one other species is unusual in comparison with most animals. Yet, the Iberian harvester ant (Messor ibericus) does one thing even stranger.

A brand new research, published in Nature, paperwork the Iberian harvester ant queen’s weird capability to clone one other species of ant (Messor structor) to mate with to supply employees.

Researchers concerned within the research carried out inhabitants genomic analyses of 390 ants from 5 Messor species throughout Europe. The evaluation revealed that M. ibericus colonies consisted of solely first-generation hybrid employees consisting of each M. ibericus and M. structor DNA, except for one Messor ponticus employee. The hybrid employees have been discovered to have an M. structor paternal ancestry and M. ibericus maternal ancestry.

However, this appeared odd to the staff, not as a result of the ants have been hybrids, however as a result of the hybrids have been discovered in lots of areas the place no M. structor colonies existed. Were queens flying lengthy distances to mate with M. structor in locations the place their colonies existed, or was one thing else happening?

“As even more compelling evidence, first-generation hybrid workers from the Italian island of Sicily are found more than a thousand kilometers away from the closest known occurrence of their paternal species. This raises the question of how queens can hybridize in such an isolated area,” the authors write.

To shed some mild on this thriller, the staff remoted M. ibericus colonies in a lab to look at egg laying, replica and improvement. To their shock, first-generation hybrids nonetheless popped up beneath these situations.

They discovered that M. ibericus queens have been cloning M. structor males utilizing saved sperm to keep up a clonal lineage of M. structor inside their colonies. This allowed them to then produce hybrid employees with the cloned males, permitting M. ibericus to broaden past the pure vary of M. structor.

Genetic evaluation of the clones revealed nuclear DNA from M. structor and mitochondrial DNA from M. ibericus. The researchers notice that this nuclear–mitochondrial genome mismatch is exclusive to males in M. ibericus colonies, and hasn’t been present in some other M. structor ants present in their very own species colonies.

This new frontier in replica is referred to by the authors as “xenoparous,” that means the ant queens have a necessity to supply people of one other species as an inherent a part of their life cycle. The actual developmental mechanism of cross-species male cloning continues to be unknown, however the authors have some theories.

They say, “Transition towards xenoparity seems to result from sexual evolution along a parasitism–mutualism continuum. Similar to several other harvester ant species, M. ibericus first transitioned into obligate sperm parasitism, a situation in which they lost the ability to produce workers by themselves due to epistatic incompatibilities or selfish caste-biasing genotypes.”

The research has left some scientists scratching their heads and questioning what it means for a species to be a species. The authors say on the topic, “Such a ‘two-species superorganism’ challenges the usual boundaries of individuality.”

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