"This is extraordinary," said Autumn, associate professor of biology at Lewis & Clark College and member of the research team. "The traditional theory is that when a species gives up sex and reproduces through cloning, the offspring will have reduced performance."
Parthenogenetic creatures are all-female species. Their "clonal" way of reproducing means that a mother's babies are genetically identical to her. A further twist to the story is that many parthenogentic species, including the Bynoe's gecko, evolved when two species crossed, or hybridized, said Michael Kearney. He is a postdoctoral research fellow in the Centre for Environmental Stress and Adaptation Research at the University of Melbourne in Australia. Kearney's interest in geckos started during his undergraduate years in Australia. As a Fulbright Graduate Fellow, Kearney studied with Autumn at Lewis & Clark College.
"This makes them a bit like mules, which are a cross between a horse and a donkey," said Kearney. "Mules are very robust animals, but they cannot reproduce." Kearney's research suggested that the hybrid forms of Bynoe's geckos could not only reproduce through parthenogenesis, but were "super tough," just like a mule.
Kearney shipped Bynoe's geckos from Sydney, Australia to Autumn's research lab in Portland, Oregon. There, Kearney, Autumn and Rebecca Wahl put the lizards through their paces on a state-of-the-art lizard treadmill. As the geckos walked in the lab at Lewis & Clark, the researchers precisely controlled the lizard's speed, body temperature, and measured how much energy the four-footers used to walk. Wahl, an alumna of Lewis & Clark, is now a doctoral student in wildlife biology at the University of Montana at Missoula.
"We found that the parthenogenetic forms were much better athletes than the sexual forms, clearly outpacing them on the treadmill," said Kearney. "This was a bit of a surprise because a similar study of another kind of parthenogenetic lizard from the deserts of the United States showed the opposite pattern."
Added Autumn: "If there was an Olympic team of Bynoe's geckos, there wouldn't be a single male on it. These geckos outperform their sexual relatives by 50 percent. They are the 'Xena: Warrior Princess' of the lizard world."
Article: "Increased Capacity for Sustained Locomotion at Low Temperature in Parthenogenetic Geckos of Hybrid Origin" Physiological and Biochemical Zoology, 78(3), May/June 2005. www.journals.uchicago.edu/PBZ/home.html