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5 December 2013 11:26 am ,
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An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Females Pick Frog Princes
18 June 1998 7:00 pm
Finicky females have long mystified both suitors and evolutionary biologists, particularly when the female tends to pick the most flamboyant male--even if he doesn't appear to have any other redeeming qualities. Some biologists have argued that the exaggerated traits are a sign of less obvious "good genes" that will lead to fitter offspring. Now an elegant series of experiments, reported in tomorrow's issue of Science, boosts that theory by showing that male tree frogs with long calls--known to be favored by females--sire higher quality young than do those with short calls.
Terse suitors don't fare well with female gray tree frogs. Females will head for long calls (up to 2 seconds) heard through a loudspeaker, even if the short calls are closer and louder, says behavioral biologist H. Carl Gerhardt from the University of Missouri, Columbia. To explore whether the longer call signaled good genes, Allison Welch, a graduate student, played Cupid. For 2 years she removed the eggs from about 10 female tree frogs, then fertilized half the eggs with sperm from a short-calling male and half with sperm from a long caller. Next, she compared how the offspring fared as tadpoles and frogs, measuring their growth rates under regimes of scarce and plentiful food. Descendants of long callers won out. "Every single significant effect was in favor of the long callers," says Gerhardt.
Other researchers praise the study because it neatly circumvents problems plaguing other "good genes" experiments, such as mothers favoring one egg over another, which alters the offspring's chances. And unlike many studies, Welch's work can rule out the possibility that in this case at least, flamboyant males offer some benefit to their offspring other than good genes, such as food or rich territories, says population geneticist Mark Kirkpatrick of the University of Texas, Austin. Male tree frogs have no contact with their offspring except for fertilization, so their only contribution is genetic.
Welch's team members say it may be a while before they can answer the next question--what makes the long callers and their descendants more fit. However, because longer calls are costly to sustain, the same genes--perhaps for stamina or more efficient metabolism--may underlie both calling and the enhanced survival of the young.