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| Fish "sticks" https://warthogterritory.net/forum/viewtopic.php?f=19&t=9036 |
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| Author: | 30mike-mike [ 17 May 2005, 05:19 ] |
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In fish, sexy mates can be easy meals, study finds http://www.sun-sentinel.com/news/custom ... ews-fringe By Tina Hesman St. Louis Dispatch Posted May 10 2005, 1:47 PM EDT Females of two species of fish prefer males with larger genitalia, a Washington University researcher has found. But while males with large sex organs are more likely to get mates, they're also more likely to be eaten by predators because their genitalia are a drag on their swimming speed. The discovery could shed light on how predators influence the formation of new species. ``It's a groundbreaking study,'' said Duncan Irschick, an evolutionary biologist at Tulane University. Sometimes male sex organs are the only thing that distinguishes one species from another, Irschick said. But scientists have been unable to fully explain the tremendous variation seen in male genitalia. The new study, published this week in the online version of the Proceedings of the National Academy of Sciences, is the first to focus on predators as an influence on genital evolution, Irschick said. R. Brian Langerhans, a graduate student at Washington University, captured small fish related to guppies. He studied two species of fish that give birth to live young _ Gambusia affinis, which he caught in ponds in Texas, and Gambusia hubbsi from the Bahamas. Some of the Texas ponds also contained predators, such as bass, bluegill and green sunfish. Other ponds were free of bigger fish. In the Bahamas, gobi and barracuda prey on the inch-long guppy relatives in some of the habitats Langerhans sampled. Both species of fish have tubelike sexual organs, called gonopodia, extending from their bellies. The organs can't be retracted, and male fish slowly wave their gonopodia in front of females to attract mates. Langerhans found that males of both species taken from predator-containing habitats had smaller sexual organs - by about 15 percent - than males from predator-free locations. ``It's not so dramatically obvious to our eyes,'' Langerhans said, but for a female fish, a 15 percent difference is huge. But it's not always easy to tell whether noticing the difference means greater attraction for mates. ``Female choice is tough, because how do you figure out what a female wants?'' Irschick said. To solve the age-old mystery, Langerhans made a video of a male and played the movie for the female side by side with film of the same male with a digitally enhanced gonopodium. Females spent about 80 percent more time with the well-endowed version. But the attraction came at a cost for the males. Males with large genitals were about 20 percent slower than males with smaller gonopodia. And slower is bad for an animal trying to evade a predator. ``If there are predators around, good luck surviving long enough to even get a chance to mate,'' Langerhans said of the more-endowed males. The finding may help explain the development of tail swords in some species of fish, Langerhans said. Males sometimes grow extensions on their tails, which humans have likened to swords, but may appear as gonopodia to female fish. Females gravitate to males with larger swords, but predators are also attracted to the tail-fin accessory. Males produce offspring with similar-size gonopodia even when raised in the laboratory without predators. That means that the trait is mostly determined by genetics and not by environment. But the presence or absence of predators can push a population toward one size extreme or another by selecting for either fleet fish or males who can attract the most mates. The tendency to gravitate to males with larger organs also seems to be hard-wired. Even females raised in environments with predators found the larger gonopodia more attractive, Langerhans found. The preference seems to defy logic - a female who gives birth to offspring with large genitals risks losing her brood to predators. But the females just can't seem to resist the males with bigger gonopodia. ``They're sexy, and their sons are going to be sexy, and that's what females want,'' Langerhans said. "Duct tape is like the Force. It has a light side, a dark side, and it holds the universe together...." - Carl Zwanzig |
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| Author: | bigross86 [ 17 May 2005, 11:34 ] |
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<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>``It's a groundbreaking study,'' <hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote> Ummm, how bored were the people who made this groundbreaking revelation? "Retreat, hell! We just got here!"-Captain Lloyd Williams, 2nd Marine Division, Belleau Wood, France, WWI |
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| Author: | 30mike-mike [ 17 May 2005, 11:37 ] |
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That's kinda what I was thinking, BR. Someone was really hurting for a graduate study! "Duct tape is like the Force. It has a light side, a dark side, and it holds the universe together...." - Carl Zwanzig |
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| Author: | TheBigThug [ 17 May 2005, 12:12 ] |
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<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote> The organs can't be retracted, and male fish slowly wave their gonopodia in front of females to attract mates. but for a female fish, a 15 percent difference is huge. But it's not always easy to tell whether noticing the difference means greater attraction for mates. ``Female choice is tough, because how do you figure out what a female wants?'' Irschick said. To solve the age-old mystery, Langerhans made a porn video of a male and played the porno for the female side by side with film of the same male with a digitally enhanced gonopodium. Females spent about 80 percent more time with the well-endowed version. But the attraction came at a cost for the males. Males with large genitals were about 20 percent slower than males with smaller gonopodia. And slower is bad for an animal trying to evade a pimp. ``If there are pimps around, good luck surviving long enough to even get a chance to mate,'' Langerhans said of the more-endowed males. The tendency to gravitate to males with larger organs also seems to be hard-wired. Even females raised in environments with pimps found the larger gonopodia more attractive, Langerhans found. The preference seems to defy logic - a female who gives birth to offspring with large genitals risks losing her brood to pimps. But the females just can't seem to resist the males with bigger gonopodia. ``They're sexy, and their sons are going to be sexy, and that's what females want,'' Langerhans said. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote> "The greatest pleasure is to vanquish your enemies, to chase them before you, to rob them of their wealth, to see their near and dear bathed in tears, to ride their horses and sleep on the white bellies of their wives and daughters." -Genghis Khan |
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| Author: | bigross86 [ 17 May 2005, 14:27 ] |
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Thankx for the translation! "Retreat, hell! We just got here!"-Captain Lloyd Williams, 2nd Marine Division, Belleau Wood, France, WWI |
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