Maccari and colleagues show that Artemia sometimes produce little baby boy Artemia. There’re at low numbers; about 1% of offspring. I am impressed by just how many Artemia they looked at to determine this:
415 666 diploid parthenogenetic Artemia specimens were sexed in this experiment(.)
But while rare overall, a few sites, mostly in the Middle East were “hotspots” of male offspring, strongly indicating that there are population differences in this ability to produce males. This, in turn suggests that there may be situations in which this ability has an evolutionary advantage. That advantage might be that these males are completely fertile, and can mate with the females of sexual species that live in the same habitats. Maccari and company discuss the possibility that there are some advantages to having gene flow between species through this mechanism.
Additional, 12 July 2013: Carl Zimmer covers this paper at The Loom.
Maccari M, Gómez A, Hontoria F, Amat F. 2013. Functional rare males in diploid parthenogenetic Artemia. Journal of Evolutionary Biology: in press. DOI: 10.1111/jeb.12191
The mystery of the rare male sea monkey
Photo by you get the picture on Flickr; used under Creative Commons license.