Some fish have all the luck

 作者:古吴蕲     |      日期:2019-02-27 04:14:00
MALE fish that win a power struggle become less stressed and more sexy, say researchers at Stanford University in California. They say the same could be true of men. The team monitored levels of cortisol, a stress hormone, in African teleost fish (Haplochromis burtoni). To reshuffle their social hierarchy, they transferred the fish to a new tank, where fish that had been dominant lost the associated bright coloration. During the struggle for territory that followed, all the males had high cortisol levels. Once new fish had established dominance, however, signalled by brighter-coloured scales, their cortisol levels fell. They also grew heavier testes and larger sex-related neurons in their brains. “When you switch an animal’s social state, the neurons change size,” says Stephanie White, an author of the report in this week’s Journal of Neuroscience (vol 17, p 6463). Her colleague Russell Fernald says that changes in social status can alter the physiology of many animals, including humans. “We can’t imagine that what we’re finding won’t be generally true,