以及，這篇文章不只適用果蠅，也適用於人類(我在說廢話，為得是接下一句話..)，
而且不只適用男性，也適用於女性，我先不說為什麼，希望你也可以想想囉~ :P
好好把妹，努力求偶，確保子孫不會越來越笨？！
各位男士們小心！不努力把妹，小心子孫越來越笨～
這篇剛剛出爐在《皇家學會報告：生物科學》的研究可有趣了！為了探討求偶的競爭過程會不會透過演化而影響到男性的心智能力，瑞士洛桑大學的科學家霍利斯（Brian Hollis）和卡維基（Tadeusz Kawecki）強制配對果蠅，讓牠們一夫一妻。公果蠅因此不用費力求偶，樂得輕鬆！
沒想到，繁衍 100 代之後，出現的果蠅後代們，整個腦殘了！！（話說，這研究真是又苦又長啊，實驗中果蠅每一代花 2 天交配、3 天產卵、再加 10 天孵化，這樣 100 代大概要四年多吧。）
這些沒有經歷求偶競爭的果蠅後代，變得比正常繁衍的果蠅後代要笨很多。例如，公果蠅的求偶能力變差，分不清環境中哪隻母果蠅在受孕期。而且，牠們的學習能力也下降。
（小聲說：重點是，只有公果蠅變笨，母果蠅無差啊！）
好，那要何看出求偶能力變差呢？簡單！研究人員讓這兩種公果蠅的後代（ 100 代後的孫子們）參加「求偶大賽」，看看哪一種公果蠅比較能夠獲得正常母果蠅的青睞。所謂的 「求偶大賽」，就是兩種公果蠅各派出五隻，然後分別和另外五隻正常公果蠅與五隻正常母果蠅關在一起，最後看看哪一種公果蠅能產下較多的後代！結果發現，沒有經歷求偶競爭的公果蠅孫子，被有經歷過求偶競爭的公果蠅孫子完敗（成功當爸爸的機率差了30%）。
那為什麼沒有經歷求偶競爭的公果蠅 100 代孫子，會被完敗呢？難不成，是因為母果蠅有血輪眼，可以一眼看出牠們是魯蛇，而不想與之交配？結果發現，事實並非如此，因為如果把單獨一隻母果蠅跟這種沒有經歷求偶競爭的公果蠅 100 代孫子關在一起，牠們的交配行為一切正常，母果蠅似乎不會排斥牠們。
嗯，那究竟是怎麼一回事呢？原來，這是因為這種沒有經歷求偶競爭的公果蠅孫子變笨了，笨到無法判斷出哪一隻母果蠅是處女蠅！研究人員發現，當這種笨公果蠅的 100 代孫子和一隻處女蠅以及五隻非處女蠅關在一起 20 分鐘後，找到處女蠅交配的成功率，比有經歷求偶競爭的公果蠅 100 孫子低了 26%，而且，成功找到處女蠅交配所花的時間（取中位數），則慢了 19 分鐘！
此外，這種沒有經歷求偶競爭的公果蠅 100 孫子的學習能力也下降（氣味 – 電擊關聯學習表現差），因此，說他們變笨，真的一點都不為過！
由此可知，如果一個社會中每個男性都不用努力求偶就能找到老婆，子孫可能會越來越笨喔！
從演化上來看，這項研究說明了求偶競爭對雄性心智能力的重要影響。在求偶過程中，如果不夠聰明，無法判斷女性的受孕狀況（套在人類身上，大概就是笨男無法判斷一個女生是否有男友、是否有老公，死會了還要硬追？），可能就會徒勞無功，被完敗打趴，淪為魯蛇慘遭淘汰。最後，只有聰明的求偶者得以成功繁衍後代。
轉貼自http://pansci.tw/archives/59292
Rivalry helps fruit flies maintain brainpower
Males dim mentally after generations without competitors
(轉貼自 https://www.sciencenews.org/arti ... maintain-brainpower)
Magazine issue: April 5, 2014
The demands of outmaneuvering other guys when courting may help male fruit flies stay mentally sharp.
After more than 100 generations in the lab without male competition, male fruit flies didn’t do so well in a standard test of learning, reports evolutionary biologist Brian Hollis of the University of Lausanne in Switzerland.
The male Drosophila melanogaster still courted with normal enthusiasm and success when alone with a female. But in groups, the long-sheltered males lagged when competing with another strain of males in siring young. A series of other tests suggests that the competition-free populations faltered not because of physical weakness but because they had lost some of their smarts for coping with complex mating crowds. Male competition and other forms of sexual selection may be unappreciated evolutionary forces for maintaining a species’ smarts, Hollis and Tadeusz Kawecki of Lausanne propose February 26 in the Proceedings of the Royal Society B.
The results don’t mean that “monogamy makes men dumb,” Hollis says. The fly experiments create a “caricature” of monogamy to study an evolutionary question. Real-world demands of reproducing, for humans as for many other animals, involve much more than being alone in a lab vial with one member of the opposite sex.
Pairing fruit flies with just one partner is how the researchers created their artificial world without male competition, starting in 2007. After 100 generations of such solitude males were still courting lone females as successfully as normal flies.
Fruit flies usually mate in crowds drawn to food. Virgin females may accept male advances after merely 10 or 20 minutes of courtship moves such as face-to-face stares and intense wing vibrations. A female who has already mated, however, is much harder for a male to persuade. “She’ll kick at him, or vibrate her wings in a characteristic way,” Hollis says. “There are lots of rejection behaviors. A male can spend hours.”
Other research has shown that males learn signs of rejection from their early attempts at courtship. When the Lausanne researchers mixed an inexperienced male from the noncompetition group with one virgin female and five mated ones likely to reject him, he did seem to learn a bit. After 20 minutes, these males were more likely to focus attention on the receptive females. But males from the normal polygamous population became even more likely to focus.
The researchers also tested learning ability with odor. They gave fly vials an earthquake shake during exposure to one odor but not when a different one wafted by. The noncompetition fruit flies didn’t score as well as the regular flies in learning to flee the earthquake smell.
Females of the noncompetition population, however, matched the odor-learning performance of regular females. Maybe the challenges of egg-laying or some other aspect of female reproduction had preserved their mental edge, the researchers speculate.
The results from the male flies run counter to research on vertebrates. Among bats and nonhuman primates, scientists found species investing more resources in brainpower when they faced less intense pressures of courting and competing.
“Primates are highly intelligent and very social; flies are not,” says evolutionary anthropologist Michael A. Schillaci of the University of Toronto Scarborough. He’s not sure the flies shed much light on primates, but they could help scientists understand mammals that don’t display a lot of social complexity.
沒想到，繁衍 100 代之後，出現的果蠅後代們，整個腦殘了！！（話說，這研究真是又苦又長啊，實驗中果蠅每一代花 2 天交配、3 天產卵、再加 10 天孵化，這樣 100 代大概要四年多吧。）
這些沒有經歷求偶競爭的果蠅後代，變得比正常繁衍的果蠅後代要笨很多。例如，公果蠅的求偶能力變差，分不清環境中哪隻母果蠅在受孕期。而且，牠們的學習能力也下降。
（小聲說：重點是，只有公果蠅變笨，母果蠅無差啊！）
好，那要何看出求偶能力變差呢？簡單！研究人員讓這兩種公果蠅的後代（ 100 代後的孫子們）參加「求偶大賽」，看看哪一種公果蠅比較能夠獲得正常母果蠅的青睞。所謂的 「求偶大賽」，就是兩種公果蠅各派出五隻，然後分別和另外五隻正常公果蠅與五隻正常母果蠅關在一起，最後看看哪一種公果蠅能產下較多的後代！結果發現，沒有經歷求偶競爭的公果蠅孫子，被有經歷過求偶競爭的公果蠅孫子完敗（成功當爸爸的機率差了30%）。
那為什麼沒有經歷求偶競爭的公果蠅 100 代孫子，會被完敗呢？難不成，是因為母果蠅有血輪眼，可以一眼看出牠們是魯蛇，而不想與之交配？結果發現，事實並非如此，因為如果把單獨一隻母果蠅跟這種沒有經歷求偶競爭的公果蠅 100 代孫子關在一起，牠們的交配行為一切正常，母果蠅似乎不會排斥牠們。
嗯，那究竟是怎麼一回事呢？原來，這是因為這種沒有經歷求偶競爭的公果蠅孫子變笨了，笨到無法判斷出哪一隻母果蠅是處女蠅！研究人員發現，當這種笨公果蠅的 100 代孫子和一隻處女蠅以及五隻非處女蠅關在一起 20 分鐘後，找到處女蠅交配的成功率，比有經歷求偶競爭的公果蠅 100 孫子低了 26%，而且，成功找到處女蠅交配所花的時間（取中位數），則慢了 19 分鐘！
此外，這種沒有經歷求偶競爭的公果蠅 100 孫子的學習能力也下降（氣味 – 電擊關聯學習表現差），因此，說他們變笨，真的一點都不為過！
由此可知，如果一個社會中每個男性都不用努力求偶就能找到老婆，子孫可能會越來越笨喔！
從演化上來看，這項研究說明了求偶競爭對雄性心智能力的重要影響。在求偶過程中，如果不夠聰明，無法判斷女性的受孕狀況（套在人類身上，大概就是笨男無法判斷一個女生是否有男友、是否有老公，死會了還要硬追？），可能就會徒勞無功，被完敗打趴，淪為魯蛇慘遭淘汰。最後，只有聰明的求偶者得以成功繁衍後代。
轉貼自http://pansci.tw/archives/59292
Rivalry helps fruit flies maintain brainpower
Males dim mentally after generations without competitors
(轉貼自 https://www.sciencenews.org/arti ... maintain-brainpower)
Magazine issue: April 5, 2014
The demands of outmaneuvering other guys when courting may help male fruit flies stay mentally sharp.
After more than 100 generations in the lab without male competition, male fruit flies didn’t do so well in a standard test of learning, reports evolutionary biologist Brian Hollis of the University of Lausanne in Switzerland.
The male Drosophila melanogaster still courted with normal enthusiasm and success when alone with a female. But in groups, the long-sheltered males lagged when competing with another strain of males in siring young. A series of other tests suggests that the competition-free populations faltered not because of physical weakness but because they had lost some of their smarts for coping with complex mating crowds. Male competition and other forms of sexual selection may be unappreciated evolutionary forces for maintaining a species’ smarts, Hollis and Tadeusz Kawecki of Lausanne propose February 26 in the Proceedings of the Royal Society B.
The results don’t mean that “monogamy makes men dumb,” Hollis says. The fly experiments create a “caricature” of monogamy to study an evolutionary question. Real-world demands of reproducing, for humans as for many other animals, involve much more than being alone in a lab vial with one member of the opposite sex.
Pairing fruit flies with just one partner is how the researchers created their artificial world without male competition, starting in 2007. After 100 generations of such solitude males were still courting lone females as successfully as normal flies.
Fruit flies usually mate in crowds drawn to food. Virgin females may accept male advances after merely 10 or 20 minutes of courtship moves such as face-to-face stares and intense wing vibrations. A female who has already mated, however, is much harder for a male to persuade. “She’ll kick at him, or vibrate her wings in a characteristic way,” Hollis says. “There are lots of rejection behaviors. A male can spend hours.”
Other research has shown that males learn signs of rejection from their early attempts at courtship. When the Lausanne researchers mixed an inexperienced male from the noncompetition group with one virgin female and five mated ones likely to reject him, he did seem to learn a bit. After 20 minutes, these males were more likely to focus attention on the receptive females. But males from the normal polygamous population became even more likely to focus.
The researchers also tested learning ability with odor. They gave fly vials an earthquake shake during exposure to one odor but not when a different one wafted by. The noncompetition fruit flies didn’t score as well as the regular flies in learning to flee the earthquake smell.
Females of the noncompetition population, however, matched the odor-learning performance of regular females. Maybe the challenges of egg-laying or some other aspect of female reproduction had preserved their mental edge, the researchers speculate.
The results from the male flies run counter to research on vertebrates. Among bats and nonhuman primates, scientists found species investing more resources in brainpower when they faced less intense pressures of courting and competing.
“Primates are highly intelligent and very social; flies are not,” says evolutionary anthropologist Michael A. Schillaci of the University of Toronto Scarborough. He’s not sure the flies shed much light on primates, but they could help scientists understand mammals that don’t display a lot of social complexity.
沒有留言:
張貼留言