[2] The two diverged recently, around 37,000 years ago, and evolved in the same geographic region, making the parasite–host pair an example of sympatric speciation.

Such relationships are not uncommon among social parasites, as recognized by Emery's rule.

Less common are cases like M. castrator's, where two species diverge without the benefit of geographic isolation, known as sympatric speciation.

This led them to rule out the possibility of recent interbreeding, and conclude that sympatric speciation had occurred.

The two species are believed to have diverged around 37,000 years ago, during the late Pleistocene.