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Ants that seem to defy biology – They lay eggs that hatch into another species

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429 points sampo | 3 comments | 19 Sep 25 12:25 UTC | HN request time: 0s | source
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corygarms ◴[19 Sep 25 15:17 UTC] No.45302603[source]▶
This is nuts. If I'm understanding correctly, the M. ibiricus queen mates with a M. structor male, uses his sperm to create sterile, hybrid female worker ants for her colony, then she (astonishingly) can also lay eggs that develop into fertile M. structor males, which means she has removed her genetic material from the egg and effectively cloned the male she previously mated with.
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sidewndr46 ◴[19 Sep 25 15:23 UTC] No.45302659[source]▶
Yeah, I came here to say the same thing. I'm really confused how the female can produce a clone of the male of another species. Wouldn't the other males sperm contain only half the genetic material needed to reproduce? But apparently ant DNA doesn't work that way for sex:

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?

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sampo ◴[19 Sep 25 16:58 UTC] No.45303877[source]▶
> I'm really confused how the female can produce a clone of the male of another species.

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.

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subroutine ◴[19 Sep 25 19:19 UTC] No.45305344[source]▶
What are the odds this behavior is not completely hostile from the side of the builder ant? There seems to be some implication of symbiotic relationship, but maybe I'm reading too much into it.

The interesting part is whether M. ibericus queens do actively remove their own genetic from eggs fertilized with builder sperm. Why would they do this?

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1. im3w1l ◴[20 Sep 25 03:57 UTC] No.45310218[source]▶
I think it's an interesting assumption that that the queen removes her own genetics from the eggs. Normally in biology I would expect the opposite, that species remove competitors in favor of their own dna. So I think the possibility should be explored that it is builder ant's sperm that is somehow removing the dna of the queen.
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2. lolc ◴[20 Sep 25 11:09 UTC] No.45312282[source]▶
Still if the foreign DNA is beneficial in keeping the hive going, it will help spread the queen's DNA. Should some allele work against the adoption of the foreign DNA, fitness drops, and that allele would become less frequent.

Who is doing the removing at fertilization is interesting mostly in a mechanical sense. The mechanisms that worked against it are being suppressed or selected out entirely.

It sure is an interesting case that one ant species is having another species promote their males if one looks at it from a gene perspective. A very weird case of symbiosis.

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3. im3w1l ◴[20 Sep 25 13:14 UTC] No.45313110[source]▶
Here's my theory of how it may have happened. Stage 0: 5 million years ago they were the same species. Stage 1: Subspecies. Ibericus and Structor became distinct populations of the same species still capable of mating. Stage 2: Parasitism. Structur became capable of replacing Ibericus dna with their own in eggs. Stage 3: Loss of function. Because of rampant structor parasitism nearly all workers were structor. So when Ibericus lost the ability to make their own workers it was a neutral mutation.

If I understand it correctly their theory is as follows. Stage 0: 5 million years ago they were the same species. Stage 1: Subspecies. Ibericus and Structor became distinct populations of the same species still capable of mating. Stage 2. Loss of function. Ibericus lost the ability to create their own workers, but as Ibericus and Structor existed in the same places hybrid workers allowed Ibericus to survive despite this. Stage 3: Ibericus learns to clone structor males to live in places where there are no Structors naturally.

Kinda interesting that even though the end result is the same who is considered the parasite is different.