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

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.

I'm no expert, but why does the female need to remove her own genetic material from her eggs to produce clones? Isn't it possible that during the DNA recombination phase the male DNA somehow dominates?

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.

> M. ibericus and M. structor are not closely related, evolutionarily speaking. The two species diverged more than five million years ago, according to the paper.

Time means nothing - species can stay stable for very long periods of time (e.g. coleocanth), and more to the point it makes no sense to call two animals different species if they can still successfully interbreed, since there then still remains the possibility that they could recombine. NOT being able to interbreed successfully (donkey & horse) marks the point of no return where they are now bound to genetically drift further apart over time.