香蕉视频

Scientists at McGill have found the answer to a question that perplexed Charles Darwin. So much so, that it actually led him to doubt his own theory of evolution. He wondered, if natural selection works at the level of the individual, fighting for survival and reproduction, how can a single colony produce worker ants that are so dramatically different in size 鈥� from the 鈥渕inor鈥� workers with their small heads and bodies, to the large-headed soldiers with their huge mandibles 鈥� especially if, as in the genus Pheidole, they are sterile? The answer, according to a paper published today in , is that the colony itself generates soldiers and regulates the balance between soldiers and 鈥渕inor鈥� workers thanks to a seemingly unimportant rudimentary 鈥渙rgan鈥� which appears only briefly during the final stages of larval development. And only in some of the ants 鈥� the ones that will become soldiers. Read more

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