Science: A fish called molly

日期:2019-03-02 06:17:06 作者:爱珊 阅读:

By GEORGINA FERRY Biologists have gained an insight into the bizarre behaviour of a male fish which helps to fertilise the eggs of an all-female fish species. Amazon mollies, found in Texas and Mexico, produce only daughters, which are exact genetic copies of their mothers. But they need male sperm to start the process of embryonic development. Their solution is to use the services of sailfin mollies, close relatives which reproduce normally. Ingo Schlupp and his colleagues at the University of Texas at Austin wondered what the male sailfins gain from this peculiar arrangement. Sailfins do not pass on their genes when they mate with Amazons, so why should such a one-sided relationship persist? Moreover, males that stick to their own kind should have more offspring. Schlupp and his colleagues believe that the male sailfins are not wasting their time after all. In experiments, they found that female sailfins were more likely to find a male attractive if they had seen him consorting with an Amazon than if they had not. It seems that when a male sailfin assists an Amazon he advertises his sexual prowess. This acts to the male’s advantage in future encounters with females of his own species (Science, vol 263,