To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie S2. Relatively large male attempting to copulate. Female on top, male on bottom. The male’s abdomen is too long for sustained copulation. Dimorphism score = - 197μm.. Rapid experimental evolution of reproductive isolation from a single natural population Scott M. Villa, Juan C. Altuna, James S. Ruff, Andrew B. Beach, Lane I. Mulvey, Erik J. Poole, Heidi E. Campbell, Kevin P. Johnson, Michael D. Shapiro, Sarah E. Bush, and Dale H. Clayton PNAS. 2019. 116:13440-13445 DOI: 10.1073/pnas.1901247116 Download Original Video Browse All Videos »