Pseudocopulation in asexual whiptail lizards

Cnemidophorus uniparens (some now call Aspidoscelis uniparens) is a species of lizard that is entirely female. The lizards reproduce asexually but still participate in pseudocopulation where two lizards mount, entwine their tails, and generally wriggle. The whiptails actually reproduce via parthenogenesis in which the chromosomes divide an additional time to complete the set in place of the set donated by a fertilizing sperm.  This means that the populations would be derived from a single individual though there could be multiple parthenogenic originators leading to intertwined populations. Multiple lines might be produced because C. uniparens is thought to have come about by the hybridization of two related species that reproduce sexually. Because of the close relatives with males and the genetic homology of an asexual species, C. uniparens makes an ideal model organism for studying the mechanisms of sex differentiation and behavior as David Crews has done for much of his career. He and his lab(s) have made up much of the background and base information for this site.