In sexual reproduction the offspring has 50% of its genetic material from both parents. In sperm parasitism the offspring is 100% related to the male and the female’s genetic material has been destroyed.
These inbericus females are allowing the messor male line to reproduce by sperm parisitism to maintain a domesticated messor line that they can then later sexually reproduce with to create hybrid worker ants.
I find it interesting that this has not led to all the clones knocked out by diseases, as happens to eg our banana plantations.
Evolution is not a particularly fast optimizer, on the scale of human perception.
Any early branch can infinitely on that confined branch. It means the billions of other possible branches may never be explored even given infinite time.
Counter would be the evolutionary fill theory where any branch can become any other branch given an environment.
https://press.uni-mainz.de/determining-sex-in-ants/
somehow a male ant has one set of chromosomes while the female ant has two sets of chromosomes. So a male ant sperm must contain enough information to make a complete male? Then when they mate with the female of the other species, the females egg actually gets blanked out so to speak, containing none of the females own genetic material. Then the male sperm fertilizes the egg with one set of chromosomes producing a male offspring that is a clone?
In normal ants, the queen can produce haploid (single set of chromosomes) unfertilized eggs that hatch into males. Normal ant males are haploid. They don't have a father, they can not have sons (but the do have a grandfather, and their daughters will make them grandsons). When the ant queen decides to produce sons, she will make haploid eggs via meiosis as normal, and just won't fertilize them with male sperm.
Ants don't have sex chromosomes. An individual with a single set of chromosomes (haploid) is a male, an individual with double set of chromosomes (diploid) is a female. Ant males are almost like sperm cells that grew into multicellular organisms.
https://en.wikipedia.org/wiki/Haplodiploidy
Now, a Messor ibericus queen can produce eggs with her own genetic material removed, and fertilize these with the single set of chromosomes from a Messor structor male. (It will still have the mitochondria and mitochondrial DNA from the queen.) And because the male only has a single set of chromosomes, the sperm and the resulting offspring has an identical single copy of the father's genetic material (except the mitochondria that came from the mother). So the son is a clone of the father (except for mitochondria).
The queen can also mate with males of her own species, contributing half of her own chromosomes to combine with the full single set of the male chromosomes, to produce to-be-queen female offspring. Here we have the normal genetic recombination (though only on the mother's side) to keep the evolutionary benefits of the variation from sexual reproduction.
Having genetic differences between males and females is mostly a bird and mammal thing, at least among vertebrates.
This confuses me too.
Did the queen once mate with one of these males and save the sperm for two years? Or are the queens somehow born with a copy of the genetic material.
Or does the old queen produce one, which mates with the new queen, and then dies off. And the new queen is able to hold onto that sperm for years (forever?). And they only produce a handful of males for this purpose?
Also why is it so difficult to have males in lab conditions?
This ability of the female to give birth to "multiple species" seems to me best understood as the two "species" not having yet actually become distinct, since the only meaningful definition of speciation is when two sub-populations of a species have genetically drifted so far apart that they can no longer successfully interbreed and produce fertile young.
During the process of speciation (one species splitting into two) there are going to be various messy half-way stages such as lions and tigers still able to interbreed and so not fully speciated (even if well along, and not going to typically interbreed), horses and donkeys still able to interbreed but producing infertile young (mules), and these ants in this strange state where interbreeding apparently only results in males. It would be cool to be able to speed up the evolutionary timescale to see the process happen, but what we have here is like a still frame from a movie.
Queens don't actually mate to produce male offspring.
Females are Diploid: They are created from a fertilized egg. They have two sets of chromosomes - one set from the mother (the queen) and one from the father's sperm, which the queen releases from the spermatheca when she wants a female.
Males are Haploid: They are created from an unfertilized egg. They have only one set of chromosomes from the queen located in the nucleas of the egg. The queen does not release the male's sperm when she wants a male offspring. They have no father. They hatch from an egg that contains only the mother's genetic material, meaning they are essentially a haploid (single chromosome set) version of the queen.
The M. ibiricus queen produces 2 kinds of offspring with the M. structor:
Sterile Female Hybrid Workers: These are produced in the standard way. The queen lays an egg (containing her genes) and fertilizes it with the sperm from the M. structor male. The resulting worker has DNA from both parents. It's a true hybrid. There is no "dominance"; it's a merger of two different species' DNA.
Fertile Male M.structor Clones: This is where things get really bizzare.
Remember that in the normal case:
- The queen does not use a male's sperm to produce male offspring.
- Joining both DNA always results in a female (males do not have two sets of chromosomes)
There can only be one conclusion. The queen creates this special clone from the male's DNA only, probably by somehow purging her DNA from the nucleus of her egg.
It is helpful to think of the whole colony as a singular organism as opposed to individuals, because our understanding of individual starts breaking down at these levels
The high-school version of evolution, playing out on an individual level, generation by generation (one baby giraffe, with a longer neck than another, reaches higher leaves and does better) gets the idea across, but evolution is about entire species not individuals, and for the most part any single genetic variation isn't going to have much impact, unless it's fatal.
The other thing to note is that integration of "foreign" genetic material also happens inside of individuals themselves, e.g. the famous cases of gut bacteria or mitochondrial DNA. One general puts a lot of emphasis on inter-species competition, e.g. predators and preys, but there's a lot of cooperation and symbiosis happening at all levels too.
In some sense the genetic feedback loop for ant population is designed in such a way that, it makes sense when looking at each ant colony as a singular organism
Unlike the giraffe, or elephants, who are individually capable of accumulating genetic variations.
Can't the organisms be viewed as individuals with a shared common goal.
The workers are involuntary but willing participants, in a grand scheme where the queens and males get to create new generations. But this is possible only if we anthropomorphise a lot.
because at the level of ants/bees I'm not even sure what "individual" even means.
But genetically they originate from the same individual, live for the betterment of the whole, and have very minor say in what happens to themselves or their genes. Much similar to cells in a human being does.
It's better than sci-fi, if you like strange creatures, dive into myrmecology.
edit: i might have that backwards
> For M. ibericus, this adaptation ensures they have plenty of workers, which are responsible for many important tasks in a colony
I don't understand this part, though. It doesn't address why it is beneficial for the workers to be hybrids instead of pure M. ibericus. At some point M. ibericus lost the ability to make non-hybrid workers, but that must have happened after.
So there are roughly three evolutionary phases:
1. Hybridization is common, but largely inconsequential.
2. Hybrid queen elimination.
3. Male cloning.
This is the third paragraph of the article:
> “The classic concept says that [a species] is a group of organisms with similar physical and genetic characteristics that can reproduce with each other in nature and produce fertile offspring,” says Xim Cerdá, an ecologist at Doñana Biological Station in Spain who was not involved with the research, to Miguel Ángel Criado at El País. “But it turns out that’s not the case; two species are needed here. We’re going to have to rethink the concept.”
The article doesn't talk about something like "carve nature at its joints"
The hybrid worker ants should still share 75% of their DNA with the queen and therefore it makes sense for them to cooperate regardless of the source of DNA for their father.
The M. structor male clones however do not share any DNA with the queen presumably.
I wouldn't be surprised if further studies found that the M. structor genes were behaving selfishly. They must have some sort of aggressive mechanism for hijacking and evicting the queen genes for making clones.
Alternatively there could be a parasitic organism propagating through the reproductive procress.
Ouch, that hurt the classicist part of my brain. Why did they choose a greek-latin hybrid word, when the rest of the field of biology uses the greek -genesis to mean birth?
2) Xenogenesis is a word that already existed before the publication of the article and using the same world could have been confusing: https://pubmed.ncbi.nlm.nih.gov/17901077/.
3) Given than we're talking about a species that lay another species in order to create hybrids, using a word that is ethymologically hybrid sounds like a perfect fit.
Create egg, remove nucleus of egg, replace nucleus of egg with one or two nuclei from stored sperm that initiate replication and growth of the other species from there (depending on the exact mechanism which it sounds like they're still figuring out).
Compared with fungus that creates zombie ants (this is a real thing - https://en.wikipedia.org/wiki/Ophiocordyceps_unilateralis) and birds that change their eggs to match those of other species (https://en.wikipedia.org/wiki/Brood_parasitism) it almost seems tame.
In this case, that happened. But if you do that, you can only expand as far as the other species expands. So you can expand further if you can find a way to keep the males of that species around with you.
This species does that by having a reproductive pathway that, if a queen is fertilized by that 'domesticated' species, the DNA of the 'host' species is removed from the eggs. So you get an ant that has none of the host's DNA. Except they do inherit the mitochondrial DNA (it always comes from the mother). The 'domesticated' males and the 'wild-type' males do look slightly different - it's not clear if this is because of the mitochondrial DNA or because they're raised differently or what.
I read someone compare the domesticated species to a 'superorganism organelle' - just like an archaea cell sucked up a bacteria to become a eukaryote, the host species sucked up the domesticated species to become some combination of both.
Wild to think what other crazy ways of living and makin babies must be out there that we haven't figured out yet.
More seriously, what those ants are doing is kind of unbelievable.
The fact this is a gross simplification that doesn't reflect reality at all is already discussed at length in the Origin of Species. "Species" is a human abstraction with no real biological reality. Almost "species" can breed and create fertile offspring with other "species". Of course as genetic distance increases the chances are increasingly unlikely, but there are some real wild cards out there.
[1] https://www.youtube.com/playlist?list=PL848F2368C90DDC3D
The egg came before the chicken.
