"Unprecedented Event in the Ant Kingdom": Queens Give Birth to Offspring from Distinct Ant Species, a Phenomenon Never Observed Before

In a groundbreaking discovery, researchers from the School of Biological Sciences at the Georgia Institute of Technology have unveiled a fascinating aspect of evolutionary biology. The study, published in the prestigious journal Nature, focuses on the ant species Messor ibericus and Messor structor.

The researchers found that the hairy male ants belong to the species M. ibericus, while their bald counterparts are from M. structor. A peculiarity of M. ibericus is that the queens produce male offspring nearly half the time, with these males either being clones of a single source of genetic material or hybrids.

Interestingly, the areas where these two species are found do not completely overlap. The offspring produced by M. ibericus queens may be hybrids, one of the two species, or something else entirely. This hybridisation raises questions about the genetic makeup of the worker ants in M. ibericus colonies, as genetic data shows that workers and queens are not genetically similar, suggesting that the workers are hybrids.

The fathers of these hybrid workers, it seems, are males of a different species, contributing paternal nuclear DNA. The mitochondrial DNA of the workers in the M. ibericus line reveals that their mothers are from M. ibericus, and their paternal DNA comes from a species called M. structor.

This reproductive mode, where M. ibericus queens mate with males of another species to produce worker ants, is a phenomenon scientists are calling xenoparous. It's worth noting that M. ibericus colonies can develop without M. structor around.

An intriguing aspect of this discovery is that M. ibericus queens can produce male offspring without their own nuclear genome, using genetic material stored in their spermatheca. This process allows sperm to enter the egg and remove the queen's own genetic material, creating males and not sterile female workers.

The question remains whether M. structor males produced by M. ibericus queens can mate and produce viable offspring with M. structor queens. Preliminary evidence suggests that 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, hinting at the possibility of successful mating.

This research provides new insights into the complex world of ant colonies and their reproductive strategies, as M. ibericus appears to be "domesticating" the M. structor ant and its genome in a unique evolutionary adaptation.