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Tree frogs that look similar hear chromosome difference in calls; Offers new insight to frog evolution

University of Missouri-Columbia


IMAGE: Carl Gerhardt, Curators Professor of Biological Sciences in the MU College of Arts and Science found female frogs can hear chromosome difference in the calls of potential mates. view more

Credit: MU News Bureau


Carl Gerhardt, Curators Professor of Biological Sciences in the MU College of Arts and Science and doctoral student Mitch Tucker studied two closely related species of grey tree frogs that live in Missouri, the eastern grey tree frog (Hyla versicolor) and the Cope's grey tree frog (H. chrysoscelis).

"To the naked eye - human and frog - the two frogs look exactly alike," Gerhardt said. "The frogs differ only in the number of chromosomes. The eastern grey tree frog has double the number of chromosomes."


"The males are both singing the same love song - just one frog is singing it slower. It's kind of like the difference between Eric Clapton's original and unplugged versions of Layla," Tucker said.



"This shows that chromosome number alone can control the behavior that keeps the species separate," Gerhardt said. "In turn, as chromosome number increases, so does the size of cells, which is probably the immediate cause of the changes in calls and preferences."



The report, titled "Parallel changes in mate-attracting calls and female preferences in autotriploid tree frogs," was published by the journal Proceedings of the Royal Society B-Biological Sciences. The study was supported by funding from the National Science Foundation, National Institutes of Health, and the University of Missouri Research Board.
