A team uncovered this bizarre reproductive trait while trying to solve the mystery of a missing ant species.
As the researchers discovered, Iberian harvester queens’ eggs develop differently depending on whether the queen needs mates to produce future Iberian harvester ant queens or a hybrid workforce that makes up 99% of the colony.
Where 2 ant species diverged Jessica Purcell, assistant professor in the Department of Entomology at the University of California, Riverside, has encountered Iberian harvester ants while studying other ant species in Italy.
2 species from 1 mother The team kept colonies of Iberian harvester ants in artificial nests in its lab.
Two Messor structor males that hatched were hairless, while three Messor ibericus males were covered with hair.
MONTPELLIER, France — Scientists have discovered a unique survival strategy in Iberian harvester ants that defies basic biology: The queens can lay eggs that give rise to two distinct ant generations.
This strange reproductive characteristic was discovered by a team investigating the disappearance of a species of ant. Initial evidence suggested that the Mediterranean region’s Iberian harvester ants, or Messor ibericus, were breeding with another harvester ant species, Messor structor, to produce hybrid worker ants.
However, there was an issue. Jonathan Romiguier, a senior researcher at the University of Montpellier in France and the senior author of a study published in September, stated that the closest known population of Messor structor ants is approximately 621 miles away from the Italian island of Sicily, where the Iberian harvester ant colony was discovered. 3 in the journal Nature, explaining the reproduction strategy of Messor ibericus.
According to Romiguier, “we had a strong suspicion that something was very unusual about this species, but to be honest, we were far from imagining just how unusual it really was.”. This contradiction prompted us to look into the matter more thoroughly. “..”.
Through five years of laboratory experiments, hundreds of ant genomes, and an analysis of over 120 ant populations throughout Europe, the team came to the startling discovery that two distinct ant species—one hairy and one nearly hairless—rose from eggs laid by a single queen.
The researchers found that the development of the eggs of Iberian harvester queens varies according to whether the queen requires mates to produce future Iberian harvester ant queens or a hybrid workforce, which comprises 99 percent of the colony.
By demonstrating that ants can produce individuals of another species as part of their life cycle, the findings are altering the way scientists think about ant reproduction.
where two ant species split off.
As Jessica Purcell, an assistant professor in the University of California, Riverside’s Department of Entomology, studied other ant species in Italy, she came across Iberian harvester ants. Purcell wrote an accompanying article to the research, but she was not a part of the new study.
She explained, “Harvester ants gather seeds from a range of plants and return them to their colony.”. There may be a ring of dense or unusual vegetation beyond the vegetation-free circles that many species create around their nest entrances by clipping the plants near them. This gives the nests a unique appearance on the outside. “.
According to the study’s authors, Messor ibericus and Messor structor were once members of the same species that split more than 5 million years ago. The two species continued to inhabit the same region of Europe even after they split apart. The species continue to coexist in some regions of the continent, like eastern France.
It is possible that Iberian harvester ant queens lost the capacity to produce female worker ants at some point, perhaps as early as several million years ago. The reason behind this phenomenon is still unknown, but it resulted in the queens mating with neighboring populations of Messor structor ants to produce a workforce that was a cross between the two species.
“As queens reproduce while workers are largely sterile, we suspect it stems from an evolutionary conflict between queens and larvae, where a so-called’selfish’ genetic element skews larval development toward becoming queens to ensure its transmission to the next generation,” Romiguier wrote in an email.
In order to survive, Iberian harvester ants had to rely on Messor structor ants, which led to sperm parasitism—the queens having to find males of another species.
The study authors claimed that instead of coping with this time-consuming annoyance, Iberian harvester ants resorted to a different method of reproduction: sexual domestication, which involves cloning the sperm of Messor structor ants. This behavior in any other animal has not yet been noticed by scientists.
According to Romiguier, “they eventually gained control over the reproduction of these males they once exploited in the wild, much like humanity domesticated livestock.”. “The ability to clone a male from a different species using only its sperm made this male domestication possible. “,”.
As a result of the ability of Iberian harvester ants to sustain a lineage of cloned male Messor structor ants within their nest over many generations, millions of invasive hybrid worker ants established colonies throughout the Mediterranean, removing the necessity for them to coexist geographically with another species.
Xeno- means “foreign, strange or different,” and -parous means “produce, bring forth, give birth,” according to Romiguier, who cited Iberian harvester ants as examples of a novel reproductive strategy known as xenoparous.
“This is the first time that we have seen the evolution of xenoparity—the need to spread the genome of another species using its own eggs—beyond ants,” Romiguier said.
A surprise genetic.
Researchers were able to identify that the only “pure” Iberian harvester ants were queens and males that could mate to create more queens by sequencing the ants’ genome. The hybrid female workers were produced by fertilizing other Iberian harvester ant eggs with Messor structor sperm.
The Iberian harvester queen ants cloned the male’s genetic material from sperm stored in their own bodies, according to research on how the queens produced Messor structor ants. The queen has the ability to remove her own nuclear DNA in some way, resulting in children that are nearly totally dependent on the sperm’s DNA.
Though it makes up less than 0.01% of the genetic material, the study found that these males have mitochondria containing Messor ibericus DNA and differ in appearance from the Messor structor males produced by Messor structor queens.
Because of their genetic similarity to their father, the clone offspring are regarded as true clones, according to Romiguier.
He added that a clone genome may develop some mutations over millions of generations and gradually diverge from the original clone.
The copy of the nuclear genome is what is commonly understood to be cloning, he stated.
One mother gives birth to two species.
Iberian harvester ant colonies were housed in the team’s lab in makeshift nests. Upon observing them for two years, the researchers saw firsthand how a single queen gave birth to two distinct species of males with unique genomes.
Three male Messor ibericus were covered in hair, whereas two male Messor structors hatched without any hair. One characteristic of ants that aids in species differentiation is hair.
The group intends to further explore the precise cellular process that leads to the cross-species cloning that Iberian harvester queens carry out.
“At this point, we know that the mother’s genetic material is extracted from the ovum, leaving only the foreign male’s genetic material in the embryo,” Romiguier stated. However, the exact mechanism and timing of the elimination of this maternal genetic material remain unknown. “.
Researchers attempting to artificially induce cloning in other species may find insights from studying the natural cloning process in ants, he said.
While androgenesis—reproduction in which the genetic material originates exclusively from the male—and hybrid offspring have been studied in other ants, the combination of both in this ant is unexpected, according to Dr. Jacobus J. Boomsma is a professor of ecology and evolution at the University of Copenhagen in Denmark’s biology department. Boomsma did not take part in the recent study.
According to Boomsma, all of the ants’ evolved traits are adaptations brought about by natural selection. By producing hybrid workers who are more fit, Iberian harvester ants were able to gain a competitive edge and greatly expand their range.
In a subsequent email, Boomsma stated, “Messor ibericus queens evolved to clone these alien males under their own steam after spreading way out of reach of natural males of Messor structor.”. The majority of genetic variation was lost in the process of stabilizing the system. This ant will therefore probably become extinct in the long run (a few million years), as nearly all asexual species do. “.”.
Iberian harvester ants have some of the strangest mating systems known to science, and Purcell referred to the discovery as novel. They also pose additional unsolved mysteries.
Determining the exact sequence in which the female reproductive system functions and the degree to which the queen has control over the outcome for every egg (e.g. 3. (will a fertilized egg develop into a worker, or will her own genetic code be purged to produce a male?) is just one of the numerous potential avenues for future research in this remarkable system,” Purcell wrote in an email. “I am eagerly anticipating what Jonathan Romiguier and his group will take on next!”.
